Battery and battery pack

Abstract

According to the battery and the battery pack provided by the invention, the battery comprises the shell, the cover plate and the adapter piece, the cover plate comprises the annular boss, and the annular boss is in interference fit with the inner wall of the shell, so that certain extrusion force is formed between the annular boss and the shell; in this way, it can be ensured that the position of the cover plate does not deviate, loosen or fall off even when the cover plate is subjected to the outward counter-acting force of the first tab, then an additional pressing tool is not needed when the cover plate and the shell are subjected to laser welding, and the welding process is simplified; the height of the annular boss is larger than 2 mm in the height direction of the battery, so that the height of the annular boss is large, the distance of the annular boss extending into the shell is long, large pressing force can be generated between the annular boss and the electrode assembly, the switching piece and the annular boss are tightly attached, and the welding quality between the annular boss and the switching piece is improved.

Description

Technical Field

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

[0002] When assembling a cylindrical battery, the casing is usually insulated from the terminals first. Then, the two ends of the electrode assembly are welded to the positive and negative electrode adapters respectively to form a whole. This whole assembly is then installed into the casing, so that the positive electrode adapter contacts the part of the terminal that extends into the casing. The two are then laser welded together to achieve the welding of the casing, terminals, positive electrode adapter, electrode assembly, and negative electrode adapter. Then, the cover plate is welded to the casing, and then the cover plate is welded to the negative electrode adapter, finally completing the assembly of the entire cylindrical battery cell.

[0003] However, during actual production, it was found that additional clamping fixtures were required during the welding process between the cover plate and the shell, making the welding process cumbersome and inconvenient for practical use. Utility Model Content

[0004] In view of this, the purpose of this application is to provide a battery and battery pack to solve or partially solve the problems raised in the prior art.

[0005] For the purposes described above, the first aspect of this application provides a battery, comprising:

[0006] The housing, including the open end;

[0007] The cover plate is welded to the end face of the opening end. The shell and the cover plate together form an accommodating space. The electrode assembly is located in the accommodating space. The electrode assembly includes a first electrode plate, a second electrode plate, and a diaphragm located between the first electrode plate and the second electrode plate, which are wound along the winding center. The first electrode plate has a first electrode tab on the side near the cover plate, and the second electrode plate has a second electrode tab on the side away from the cover plate.

[0008] An adapter plate is disposed between the electrode assembly and the cover plate and is welded to the first electrode tab;

[0009] The cover plate includes an annular boss, which is interference-fitted with the inner wall of the housing. The bottom surface of the annular boss is welded to the outer periphery of the adapter piece. The height of the annular boss is greater than 2mm in the height direction of the battery.

[0010] Optionally, the adapter plate includes a welding ring, which is welded to an annular protrusion.

[0011] Optionally, in the height direction of the battery, the height of the first tab is greater than the height of the second tab.

[0012] Optionally, the height difference between the first electrode and the second electrode is less than or equal to the height of the annular boss.

[0013] Optionally, the height of the first electrode tab is greater than or equal to 1.5 mm, and / or the height difference between the first electrode tab and the second electrode tab is greater than or equal to 0.5 mm.

[0014] Optionally, the first tab includes a first tab region and a second tab region. In the radial direction of the electrode assembly, the first tab region is located on the side of the second tab region away from the winding center. The orthographic projection of the first tab region on the first plane at least partially coincides with the orthographic projection of the annular boss on the first plane. The first plane is a plane perpendicular to the central axis of the housing. In the height direction of the battery, the height of the first tab region is greater than the height of the second tab region.

[0015] Optionally, the height difference between the first tab region and the second tab region is less than or equal to the height of the annular boss.

[0016] Optionally, in the height direction of the battery, the first tab includes a densely stacked region and a loosely stacked region arranged sequentially, the densely stacked region is welded to the adapter piece, and the stacking density of the first tab in the loosely stacked region is less than the stacking density of the first tab in the densely stacked region.

[0017] Optionally, in the height direction of the battery, each loop of the first tab in the stacked loose region includes at least two layers stacked together.

[0018] The second aspect of this application provides a battery pack, including the battery of any one of the first aspects described above, wherein the battery pack is a battery pack or a battery module.

[0019] As can be seen from the above, the battery and battery pack provided in this application include a battery housing, a cover plate, and an adapter plate. The cover plate includes an annular boss, which is interference-fitted with the inner wall of the housing, resulting in a certain compressive force between them. This ensures that the cover plate will not shift, loosen, or fall off even when subjected to the outward reaction force of the first electrode tab. Consequently, no additional clamping fixture is required when laser welding the cover plate and the housing, simplifying the welding process. In the height direction of the battery, the height of the annular boss is greater than 2mm. Thus, the height of the annular boss is relatively high, and its extension distance into the housing is relatively long, which allows for a larger clamping force between the annular boss and the electrode assembly. This ensures that the adapter plate and the annular boss are tightly attached, improving the welding quality between the annular boss and the adapter plate. Attached Figure Description

[0020] 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.

[0021] Figures 1a to 1c A schematic diagram of different assembly stages in the existing battery assembly process is shown;

[0022] Figure 2 A first cross-sectional schematic diagram of a battery according to an embodiment of this application is shown;

[0023] Figure 3 A schematic diagram of a first structure of an electrode assembly according to an embodiment of this application is shown;

[0024] Figure 4 A second cross-sectional schematic diagram of a battery according to an embodiment of this application is shown;

[0025] Figure 5 It shows Figure 4 A magnified view of part of C;

[0026] Figure 6 A second structural schematic diagram of the electrode assembly according to an embodiment of this application is shown;

[0027] Figure 7 A schematic diagram of the first electrode sheet according to an embodiment of this application is shown;

[0028] Figure 8 This illustration shows another partially enlarged schematic diagram of a battery according to an embodiment of this application.

[0029] In the figure: 1. Shell; 11. Open end; 2. Cover plate; 21. Cover plate body; 22. Annular boss; 3. Adapter piece; 31. Welding ring; 32. Electrode tab welding part; 4. Electrode assembly; 41. First electrode; 411. First electrode tab; 4111. First electrode tab area; 4112. Second electrode tab area; 4113. Densely stacked area; 4114. Loosely stacked area; 4115. Flat area; 412. First active coating; 42. Second electrode; 421. Second electrode tab; 422. Second active coating; 5. Fusion welding structure; 6. Electrode post; 7. Positive electrode adapter piece; 8. Negative electrode adapter piece. Detailed Implementation

[0030] 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.

[0031] 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.

[0032] Current batteries typically include a casing and an electrode assembly housed within the casing, which is filled with an electrolyte. The electrode assembly is mainly formed by stacking or winding a first electrode and a second electrode with opposite polarities, and a separator is usually provided between the first and second electrodes. The portions of the first and second electrodes coated with active material constitute the main body of the electrode assembly, while the portions of the first and second electrodes not coated with active material constitute the first tab and the second tab, respectively. In lithium-ion batteries, the first electrode can be a positive electrode, including a positive current collector and positive active material layers disposed on both sides of the positive current collector. The material of the positive current collector can be, for example, aluminum, and the positive active material can be, for example, lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc.; the second electrode can be a negative electrode, including a negative current collector and negative active material layers disposed on both sides of the negative current collector. The material of the negative current collector can be, for example, copper, and the negative active material can be, for example, graphite or silicon, etc.

[0033] The first and second tabs can be located together at one end of the main body or at opposite ends of the main body. During the charging and discharging process of the battery cell, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals to form a current loop.

[0034] For cylindrical battery cells, 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 the positive adapter plate, and the negative tab is connected to the negative adapter plate.

[0035] Figures 1a to 1c The diagram illustrates different assembly stages in the existing battery assembly process.

[0036] See figure Figure 1a , Figure 1b , Figure 1cAs shown, in actual assembly, the housing 1 is usually first insulated from the terminal 6. Then, the two ends of the electrode assembly 4 are welded to the positive electrode adapter 7 and the negative electrode adapter 8 respectively to form a whole. This whole assembly is then installed into the housing 1, so that the positive electrode adapter 7 contacts the part of the terminal 6 that extends into the housing. Then, the two are laser welded together to achieve the welding of the housing 1, terminal 6, positive electrode adapter 7, electrode assembly 4, and negative electrode adapter 8. The welded battery is as follows: Figure 1a As shown.

[0037] Then, overlap or press the cover plate 2 onto the housing 1, and the battery after overlap is as follows: Figure 1b As shown, the overlapped cover plate 2 and housing 1 are transported to the next process for laser welding. After the cover plate 2 and housing 1 are laser welded, the cover plate 2 is then welded to the negative electrode adapter piece 8.

[0038] However, during actual production, the inventors discovered that when the cover plate 2 is overlapped or pressed onto the housing 1, the cover plate 2 will exert a downward squeezing force on the electrode assembly 4 inside the housing 1 to confine the electrode assembly 4 inside the housing 2. At this time, the tabs of the electrode assembly 4 will generate an outward reaction force on the cover plate 2.

[0039] Because the overlap between the cover plate 2 and the housing 1 results in insufficient clamping force between the cover plate 2 and the housing 1, the cover plate 2 is easily pushed out by the reaction force of the tabs of the battery assembly 4 during transportation (e.g., Figure 1c As shown in the figure, this can lead to the cover plate 2 shifting or falling off. Therefore, when laser welding the cover plate 2 to the housing 1, additional clamping fixtures must be used to clamp the cover plate 2 before the welding process can be carried out, which makes the welding process cumbersome and inconvenient for practical use.

[0040] In addition, when the cover plate 2 is welded to the negative electrode adapter piece 8, the clamping force of the cover plate 2 is insufficient, resulting in insufficient clamping force of the cover plate 2 on the negative electrode tab. Consequently, the cover plate 2 and the negative electrode adapter piece 8 cannot be tightly pressed together, resulting in poor welding quality between the cover plate 2 and the negative electrode adapter piece 8.

[0041] Therefore, how to improve the clamping force between the cover plate 2 and the housing 1, as well as the degree of clamping and fit between the cover plate 2 and the negative electrode adapter piece 8, is an urgent problem to be solved.

[0042] Based on this, this application provides a battery.

[0043] Figure 2 A first cross-sectional schematic diagram of a battery according to an embodiment of this application is shown. Figure 3 A schematic diagram of a first structure of an electrode assembly according to an embodiment of this application is shown.

[0044] See Figure 2 and Figure 3As shown, the battery in this embodiment of the application includes:

[0045] The housing 1 includes an open end 11;

[0046] The cover plate 2 is welded to the end face of the opening end 11, and the shell 1 and the cover plate 2 together form an accommodating space;

[0047] Electrode assembly 4, including along the winding center (i.e. Figure 3 (As shown in K) A first electrode 41, a second electrode 42 and a diaphragm located between the first electrode 41 and the second electrode 42 are wound together. The first electrode 41 has a first electrode tab 411 on the side near the cover plate 2 and the second electrode 42 has a second electrode tab 421 on the side away from the cover plate 2.

[0048] The adapter piece 3 is disposed between the electrode assembly 4 and the cover plate 2, and is welded to the first electrode tab 411;

[0049] The cover plate 2 includes an annular boss 22, which is interference-fitted with the inner wall of the housing 1. The bottom surface of the annular boss 22 is welded to the outer periphery of the adapter piece 3. In the height direction of the battery, the height of the annular boss 22 is greater than 2mm.

[0050] Specifically, the housing 1 has an opening at its open end 11, and the cover plate 2 is used to cover the opening. The cover plate 2 and the housing 1 together form a receiving space, which is used to receive the battery electrode assembly 4.

[0051] Electrode assembly 4 includes components along the winding center (i.e. Figure 3 As shown in K, a first electrode 41, a second electrode 42, and a diaphragm are wound together and arranged. The first electrode 41 has a first tab 411 on the side near the cover plate 2, and the second electrode 42 has a second tab 421 on the side away from the cover plate 2. The first electrode 41 includes a first active coating 412 and a first tab 411. The first active coating 412 is the area on the first electrode 41 coated with active material, and the first tab 411 is the area on the first electrode 41 not coated with active material. The second electrode 42 includes a second active coating 422 and a second tab 421. The second active coating 422 is the area on the second electrode 42 coated with active material, and the second tab 421 is the area on the second electrode 42 not coated with active material.

[0052] For example, the first electrode 41 can be a negative electrode, the second electrode 42 can be a positive electrode, the first active coating 412 can be a negative active material layer, the first tab 411 can be a negative tab, the second active coating 422 can be a positive active material layer, and the second tab 421 can be a positive tab.

[0053] The cover plate 2 includes an annular boss 22, which is located inside the housing 1. The annular boss 22 can prevent the laser from entering the electrode assembly 4 inside the battery when the cover plate 2 is laser welded to the housing 1, thus ensuring that the electrode assembly 4 will not be damaged.

[0054] The annular boss 22 is interference-fitted with the inner wall of the housing 1, which creates a certain compressive force between them. This compressive force ensures that the annular boss 22 and the inner wall of the housing 1 are tightly pressed together. Thus, during the transportation of the cover plate 2 and the housing 1 after the interference fit, even if the first tab 411 still applies an outward reaction force to the cover plate 2, this reaction force is not enough to separate the tightly pressed cover plate 2 and the housing 1. This ensures that the position of the cover plate 2 will not shift, loosen or fall off, thereby eliminating the need for additional clamping fixtures when laser welding the cover plate 2 and the housing 1, simplifying the welding process.

[0055] In the height direction of the battery (i.e.) Figure 2 As shown in H), the height of the annular boss 22 (i.e. Figure 2 As shown in Figure a), the height of the annular boss 22 is greater than 2mm, thus the height of the annular boss 22 is relatively high and the distance it extends into the housing 1 is relatively long. This allows the annular boss 22 and the electrode assembly 4 to generate a large clamping force, making the adapter piece 3 and the annular boss 22 fit tightly together, thereby improving the welding quality between the annular boss 22 and the adapter piece 3.

[0056] Figure 4 A second cross-sectional schematic diagram of a battery according to an embodiment of this application is shown. Figure 5 It shows Figure 4 A magnified view of part C in the diagram.

[0057] In some embodiments, see Figure 4 and Figure 5 The battery also includes an adapter piece 3, which is located inside the housing 1. The adapter piece 3 includes a welding protrusion ring 31, which is welded to an annular protrusion 22.

[0058] Specifically, the annular boss 22 is welded to the welding protrusion 31 on the adapter piece 3. Both the annular boss 22 and the welding protrusion 31 are annular structures. This results in a smaller contact area between the adapter piece 3 and the annular boss 22, leading to a better fit between the adapter piece 3 and the cover plate 2, which is beneficial for improving welding quality. If the entire plane of the adapter piece 3 were welded to the entire plane of the cover plate 2, a complete fit between two larger planes would be more difficult than the fit between two annular structures, potentially creating gaps and reducing welding quality. Therefore, in this application, by providing the annular boss 22 and the welding protrusion 31, the fit between the cover plate 2 and the adapter piece 3 can be improved, thereby enhancing the welding effect.

[0059] In this application, by increasing the height of the annular boss 22, the distance it extends into the housing 1 is increased, thereby ensuring a tight seal between the annular boss 22 and the inner wall of the housing 1. This eliminates the need for additional clamping fixtures when laser welding the cover plate and the housing, simplifying the welding process. Furthermore, the annular boss 22 also more easily and tightly fits with the welding protrusion 31 on the adapter piece 3, thus ensuring a good welding effect between the annular boss 22 and the welding protrusion 31.

[0060] However, increasing the height of the annular boss 22 has a drawback: the higher annular boss 22 will exert greater compressive force on the electrode assembly 4, which can easily cause overpressure on the electrode assembly 4, and thus cause the first active coating 412 or the second active coating 422 on the first electrode 41 or the second electrode 42 in the electrode assembly 4 to fall off, affecting the battery's service life.

[0061] Based on this, in some embodiments, see Figure 6 , Figure 6 The second structural schematic diagram of the electrode assembly 4 according to the embodiment of this application shows that, in the height direction of the battery, the height of the first electrode tab 411 is controlled (i.e., Figure 6 (As shown in d) is greater than the height of the second electrode 421 (i.e. Figure 6 (as shown in c).

[0062] Specifically, the tabs are usually made of copper or aluminum foil, which are relatively soft and easily deformed.

[0063] The first electrode tab 411 is located close to the cover plate 2, that is, the first electrode tab 411 is connected to the cover plate 2 through the adapter piece 3. The second electrode tab 421 is located away from the cover plate 2, that is, the second electrode tab 421 is connected to the pole on the housing 1.

[0064] In this application, the height of the first tab 411 is controlled in the height direction of the battery (i.e., Figure 6 (As shown in d) is greater than the height of the second electrode 421 (i.e. Figure 6 As shown in Figure c), the overall height of the first tab 411 is relatively high. When the high annular boss 22 applies a large compressive force to the electrode assembly 4, the softer and higher first tab 411 can absorb this large compressive force, providing a certain buffering effect and preventing the compressive force from reaching the first active coating 412 connected to the first tab 411. This protects the first active coating 412 from excessive compressive force and prevents it from falling off. In addition, when subjected to large compressive force, the high first tab 411 can also provide a large reaction force to the annular boss 22 and the welding ring 31, providing better support for the annular boss 22 and the welding ring 31 and ensuring the welding effect of both.

[0065] It is worth noting that the tabs (first tab 411 and second tab 421) refer to the areas on the electrode sheet that are not coated with active material. After the electrode assembly 4 is wound, the tabs are smoothed / flattened. In this application, the height of the tab includes the sum of the height of the unsmoothed / flattened portion of the tab and the height of the smoothed / flattened portion of the tab, wherein the height of the unsmoothed / flattened portion of the tab is the height of the straight section of the tab, and the height of the smoothed / flattened portion of the tab is the height after smoothing / flattening.

[0066] In some embodiments, the height difference between the first tab 411 and the second tab 421 is less than or equal to the height of the annular boss 22. Thus, the height difference between the first tab 411 and the second tab 421 is appropriate, ensuring that the height of the first tab 411 is sufficient to provide an effective buffer against the compressive force exerted by the annular boss 22 on the electrode assembly 4, thereby protecting the first active coating 412 from excessive compressive force and preventing it from peeling off, while also avoiding excessive reduction in the energy density of the battery.

[0067] If the height difference between the first tab 411 and the second tab 421 is greater than the height of the annular boss 22, then the height of the first tab 411 is very high. Although it is sufficient to provide an effective buffer against the squeezing force exerted by the annular boss 22 on the electrode assembly 4, the excessive height of the first tab 411 results in a smaller area of ​​the first active coating 412 on the first electrode 41, thereby reducing the energy density of the battery.

[0068] For example, the height of the first tab 411 is greater than or equal to 1.5 mm, and / or the height difference between the first tab 411 and the second tab 421 is greater than or equal to 0.5 mm, so as to ensure that the first tab 411 can provide effective buffering against the compressive force applied by the annular boss 22 to the electrode assembly 4, and protect the first active coating 412 from peeling off.

[0069] Therefore, in this application, controlling the height difference between the first tab 411 and the second tab 421 to be less than or equal to the height of the annular boss 22 can both enable the first tab 411 to provide an effective buffer against the squeezing force exerted by the annular boss 22 on the electrode assembly 4, thus protecting the first active coating 412, and avoid significantly reducing the energy density of the battery.

[0070] In this application, although controlling the height difference between the first tab 411 and the second tab 421 to be less than or equal to the height of the annular boss 22 will not significantly reduce the energy density of the battery, it will still have a certain impact on the energy density of the battery.

[0071] Based on this, in order to further improve the impact on battery energy density while ensuring that the first tab 411 can effectively buffer the squeezing force applied by the annular boss 22 to the electrode assembly 4, this application has further optimized the first tab 411.

[0072] Figure 7 A schematic diagram of the first electrode 41 according to an embodiment of this application is shown.

[0073] In some embodiments, see continue to see Figure 6 and Figure 7 The first electrode 411 includes a first electrode region 4111 and a second electrode region 4112, in the radial direction of the electrode assembly 4 (i.e. Figure 6 and Figure 7 (As shown in direction A), the first tab region 4111 is located on the side of the second tab region 4112 away from the winding center. The orthographic projection of the first tab region 4111 on the first plane at least partially coincides with the orthographic projection of the annular boss 22 on the first plane. The first plane is a plane perpendicular to the central axis of the housing 1. In the height direction of the battery, the height of the first tab region 4111 is greater than the height of the second tab region 4112.

[0074] Specifically, in the radial direction of the electrode assembly 4, the first tab region 4111 is located on the side of the second tab region 4112 away from the winding center. That is, for the wound electrode assembly 4, the first tab region 4111 is located in the outer winding area of ​​the electrode assembly 4, and the second tab region 4112 is located in the inner winding area of ​​the electrode assembly 4.

[0075] The orthographic projection of the first tab region 4111 onto the first plane at least partially coincides with the orthographic projection of the annular boss 22 onto the first plane. That is, the first tab region 4111 at least partially corresponds to the area where the annular boss 22 is located. In other words, when the higher annular boss 22 applies a large compressive force to the electrode assembly 4, the area bearing this compressive force is the first tab region 4111 corresponding to the annular boss 22. Therefore, the first tab region 4111 is the region most susceptible to overpressure, while the second tab region 4112 is relatively less susceptible to overpressure.

[0076] Based on this, in this application, the height of the first tab region 4111 is controlled to be greater than the height of the second tab region 4112 in the height direction of the battery. Thus, the first tab region 4111 is higher, and when the higher annular boss 22 applies a large compressive force to the electrode assembly 4, the softer and higher first tab region 4111 can absorb this large compressive force, providing a certain buffering effect and preventing the compressive force from reaching the first active coating 412 connected to the first tab region 4111. This can protect the first active coating 412 from being subjected to too much compressive force and thus prevent it from falling off. In addition, when subjected to large compressive force, the higher first tab region 4111 can also provide a larger reaction force to the annular boss 22 and the welding ring 31, so as to provide better support for the annular boss 22 and the welding ring 31 and ensure the welding effect of the two.

[0077] Meanwhile, the height of the second tab region 4112 is relatively small, which makes the height of the first active coating 412 region connected to the second tab region 4112 relatively high. In this way, it will not affect the coating area of ​​the first active coating 412 of the first electrode 41, and thus will not reduce the energy density of the battery.

[0078] In this application, only the height of the first tab region 4111, which is easily over-voltaged, is increased, while the height of the second tab region 4112, which is not easily over-voltaged, is not increased. This ensures that the higher height of the first tab region 4111 can provide an effective buffer against the squeezing force exerted by the annular boss 22 on the electrode assembly 4. At the same time, increasing the height of the first tab region 4111 will not significantly affect the coating area of ​​the first active coating 412 of the first electrode 41, so it will not reduce the energy density of the battery.

[0079] In some embodiments, the height difference between the first tab region 4111 and the second tab region 4112 is less than or equal to the height of the annular boss 22. Thus, the height difference between the first tab region 4111 and the second tab region 4112 is appropriate, ensuring that the height of the first tab region 4111 is sufficient to provide an effective buffer against the compressive force exerted by the annular boss 22 on the electrode assembly 4, thereby protecting the first active coating 412 from excessive compressive force and preventing it from falling off, while also avoiding any impact on the energy density of the battery.

[0080] If the height difference between the first tab region 4111 and the second tab region 4112 is greater than the height of the annular boss 22, then the height of the first tab region 4111 is very high. Although it is sufficient to provide an effective buffer against the squeezing force exerted by the annular boss 22 on the electrode assembly 4, the excessive height of the first tab region 4111 results in a smaller area of ​​the first active coating 412 on the first electrode 41, thereby reducing the energy density of the battery.

[0081] For example, the height of the first tab region 4111 is greater than or equal to 1.5 mm, and / or the height difference between the first tab region 4111 and the second tab region 4112 is greater than or equal to 0.5 mm, so as to ensure that the first tab region 4111 can provide effective buffering against the extrusion force applied by the annular boss 22 to the electrode assembly 4, and protect the first active coating 412 from falling off.

[0082] Therefore, in this application, controlling the height difference between the first tab region 4111 and the second tab region 4112 to be less than or equal to the height of the annular boss 22 can both provide an effective buffering effect for the first tab region 4111 to withstand the squeezing force exerted by the annular boss 22 on the electrode assembly 4, thus protecting the first active coating 412, and without reducing the energy density of the battery.

[0083] Figure 8 This illustration shows another partially enlarged schematic diagram of a battery according to an embodiment of this application.

[0084] In some embodiments, the adapter plate 3 further includes a tab welding portion 32, which is located on the side of the welding protrusion ring 31 away from the cover plate 2, and the tab welding portion 32 is welded to the first tab 411.

[0085] Specifically, the electrode welding part 32 has a planar circular structure, which facilitates welding with the first electrode 411.

[0086] In specific implementation, the first electrode tab 411 can be a full electrode tab structure. During assembly, the first electrode tab 411 of the full electrode tab structure is flattened to facilitate welding with the electrode tab welding part 32. In this case, the flattened electrode tab end face is a dense end face.

[0087] The first tab 411 can also be a cut tab structure, that is, the full tab structure is cut into multiple tab pieces. During assembly, the multiple tab pieces can be directly smoothed out without the need for kneading. In this case, the flatness of the flattened tab end face is better.

[0088] In some embodiments, in the height direction of the battery, the first tab 411 includes a densely stacked region 4113, a loosely stacked region 4114, and a straight region 4115 arranged sequentially. The densely stacked region 4113 is welded to the adapter piece 3, the straight region 4115 is connected to the first active coating 412, and the loosely stacked region 4114 is located between the densely stacked region 4113 and the straight region 4115. The stacking density of the first tab 411 in the loosely stacked region 4114 is less than the stacking density of the first tab 411 in the densely stacked region 4113.

[0089] Specifically, the stacking density refers to the density in the radial direction of housing 1 (i.e., Figure 8(as shown in direction B in the diagram), the stacking density of the first tabs 411. In the radial direction of the housing 1, the larger the gap between two adjacent rings of first tabs 411, the smaller their stacking density and the looser the stacking density; the smaller the gap between two adjacent rings of first tabs 411, the larger their stacking density and the tighter the stacking density.

[0090] Among them, after the electrode assembly 4 is wound, the first electrode tab 411 includes multiple turns, and each turn of the first electrode tab 411 extends along the circumference of the shell.

[0091] In this application, the stacking density of the first tab 411 in the loosely stacked region 4114 is less than that in the densely stacked region 4113. Thus, the stacking of the first tab 411 in the loosely stacked region 4114 is relatively loose, and the gap between two adjacent rings of first tabs 411 is larger. In this way, when the higher annular boss 22 applies a large compressive force to the electrode assembly 4, the loosely stacked first tabs can be further compressed under the compressive force. Thus, the loosely stacked region 4114 can provide a further buffering effect on the compressive force applied by the annular boss 22 to the electrode assembly 4, protecting the first active coating 412 from being subjected to too much compressive force, and thus preventing it from falling off.

[0092] In some embodiments, in the height direction of the battery, each ring of the first tab 411 of the stacked loose area 4114 includes at least two stacked layers, so that the at least two stacked layers can be further compressed under the action of extrusion force to further enhance the buffering effect of the first tab 411 on the extrusion force applied by the annular boss 22 to the electrode assembly 4.

[0093] In specific implementation, the densely stacked area 4113, the loosely stacked area 4114, and the flat area 4115 of the first electrode tab 411 can be formed by a flattening process. Similarly, the flattening process can also make each ring of the first electrode tab 411 in the loosely stacked area 4114 include at least two stacked layers.

[0094] In this application, by optimizing the structure of the cover plate 2 and the adapter piece 3, the welding effect between the cover plate 2 and the adapter piece 3, as well as between the cover plate 2 and the housing 1, can be improved. By optimizing the structure of the first electrode tab 411, the first electrode tab 411 can provide an effective buffering effect on the extrusion force applied by the annular boss 22 to the electrode assembly 4, thereby protecting the active coating from excessive extrusion force and preventing the active coating from falling off.

[0095] This application also provides a battery pack, including the battery of any of the above embodiments, wherein the battery pack can be a battery pack or a battery module.

[0096] Specifically, the battery pack includes a housing and at least one battery. The housing includes a first housing section and a second housing section, which are fitted together to form a receiving space, in which at least one battery is housed. When multiple batteries are provided, they can be connected in series and / or in parallel.

[0097] 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.

[0098] 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 battery, characterized in that, include: The housing, including the open end; A cover plate is welded to the end face of the opening, and the housing and the cover plate together form an accommodating space; An electrode assembly is located within the receiving space. The electrode assembly includes a first electrode, a second electrode, and a diaphragm located between the first electrode and the second electrode, all wound along a winding center. The first electrode has a first tab on the side near the cover plate, and the second electrode has a second tab on the side away from the cover plate. An adapter piece is disposed between the electrode assembly and the cover plate, and is welded to the first electrode tab; The cover plate includes an annular boss, which is interference-fitted with the inner wall of the housing. The bottom surface of the annular boss is welded to the outer periphery of the adapter piece. The height of the annular boss is greater than 2mm in the height direction of the battery.

2. The battery according to claim 1, characterized in that, The adapter plate includes a welding protrusion ring, which is welded to the annular boss.

3. The battery according to claim 1, characterized in that, In the height direction of the battery, the height of the first tab is greater than the height of the second tab.

4. The battery according to claim 3, characterized in that, The height difference between the first electrode and the second electrode is less than or equal to the height of the annular boss.

5. The battery according to claim 3, characterized in that, The height of the first electrode tab is greater than or equal to 1.5 mm, and / or the height difference between the first electrode tab and the second electrode tab is greater than or equal to 0.5 mm.

6. The battery according to claim 1, characterized in that, The first tab includes a first tab region and a second tab region. In the radial direction of the electrode assembly, the first tab region is located on the side of the second tab region away from the winding center. The orthographic projection of the first tab region on a first plane at least partially coincides with the orthographic projection of the annular boss on the first plane. The first plane is a plane perpendicular to the central axis of the housing. In the height direction of the battery, the height of the first tab region is greater than the height of the second tab region.

7. The battery according to claim 6, characterized in that, The height difference between the first tab region and the second tab region is less than or equal to the height of the annular boss.

8. The battery according to claim 2, characterized in that, In the height direction of the battery, the first tab includes a densely stacked area and a loosely stacked area arranged sequentially. The densely stacked area is welded to the adapter piece. The stacking density of the first tab in the loosely stacked area is less than the stacking density of the first tab in the densely stacked area.

9. The battery according to claim 8, characterized in that, In the height direction of the battery, each loop of the first tab in the stacked loose region includes at least two layers stacked together.

10. A battery pack, characterized in that, The battery includes the battery as described in any one of claims 1 to 9, wherein the battery pack is a battery pack or a battery module.

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