Battery monomer, battery and electric equipment

Abstract

The utility model relates to a battery monomer, a battery and electric equipment. The battery cell comprises: a housing having an accommodating cavity; the pole column is arranged on the shell; the battery cell is accommodated in the accommodating cavity, and one end, facing the pole, of the battery cell is provided with a first tab; the collector plate is accommodated in the accommodating cavity and is positioned between the battery cell and the pole; the collector plate is provided with a first welding area, a second welding area arranged around the first welding area and a transition area located between the first welding area and the second welding area, and the thickness of the first welding area is larger than that of the second welding area; wherein the first welding area protrudes towards the pole relative to the second welding area, so that a boss is formed on the side, facing the pole, of the current collecting disc, a groove is formed in the side, deviating from the pole, of the current collecting disc, the boss is welded to the pole, the second welding area is welded to the first tab, and an annular step arranged around the boss is formed in the transition area.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and specifically to a battery cell, a battery, and an electrical device. Background Art

[0002] Lithium-ion batteries, with their high energy density, long cycle life, excellent rate capability, safety, and environmental friendliness, are essential energy sources for modern electronics and electric vehicles. Furthermore, steel-cased cylindrical lithium-ion batteries offer a uniform design, a high degree of production automation, excellent cell consistency, and convenient assembly and design. They are the preferred choice for electronics and electric vehicles, and are finding increasing scale in their application.

[0003] Existing cylindrical lithium batteries typically include a cell, a current collector, and a pole. The current collector has two welding areas, one for welding to the cell's tab, and the other for welding to the pole, thereby achieving electrical connection between the cell's tab, the current collector, and the pole. Typically, the thickness of the current collector is thinner than the thickness of the pole the laser penetrates, and the thickness of the tab the laser penetrates is much thinner than the thickness of the pole the laser penetrates. Because the difference between the thickness of the current collector and the thickness of the pole the laser penetrates is too large, when the laser penetrates the pole and reaches the current collector, the collector may not be able to withstand the laser energy and burn through. If the laser energy is reduced, the laser may not be able to penetrate the pole, resulting in a cold weld, which has a serious adverse effect on the welding quality and greatly reduces the battery's current capacity. Utility Model Content

[0004] Based on this, it is necessary to provide a battery cell, a battery and an electrical device that can improve the welding quality of the current collecting plate and enhance the current carrying capacity of the battery in order to address the above problems.

[0005] A battery cell, comprising:

[0006] The shell has a receiving cavity;

[0007] A pole, arranged on the housing;

[0008] A battery cell is accommodated in the accommodation cavity, and one end of the battery cell facing the pole has a first tab; and

[0009] a current collecting plate received in the receiving cavity and located between the battery cell and the pole; the current collecting plate having a first welding area, a second welding area arranged around the first welding area, and a transition area located between the first welding area and the second welding area, wherein the thickness of the first welding area is greater than the thickness of the second welding area;

[0010] The first welding area is arranged to protrude toward the pole relative to the second welding area to form a boss on the side of the collecting plate facing the pole, and a groove is formed on the side of the collecting plate away from the pole. The boss is welded to the pole, and the second welding area is welded to the first tab. The transition area is formed with an annular step arranged around the boss.

[0011] In some embodiments, the thickness of the first welding region is 0.40 mm to 0.80 mm, and the thickness of the second welding region is 0.15 mm to 0.35 mm.

[0012] In some embodiments, the difference in thickness between the first welding region and the second welding region is 0.1 mm-0.4 mm.

[0013] In some embodiments, the first welding region, the second welding region, and the transition region of the collecting plate are integrally stamped from a plate material of the same thickness.

[0014] In some embodiments, the pole has a first blind hole on the side facing the collecting plate for accommodating the boss, and the first blind hole, the boss and the annular step are coaxially arranged; wherein the diameter D3 of the first blind hole is larger than the outer diameter D5 of the annular step.

[0015] In some embodiments, the first blind hole includes a bottom wall and a side wall arranged around the bottom wall, the boss contacts and is welded to the bottom wall, and a gap is formed between the side wall and the boss;

[0016] The depth of the first blind hole is smaller than the height of the boss protruding from the annular step.

[0017] In some embodiments, the diameter of the weld mark formed by welding the boss to the bottom wall is a preset value D1; the side of the pole facing away from the collecting plate has a second blind hole coaxial with the first blind hole, and the diameter D2 of the second blind hole and the outer diameter D4 of the boss satisfy: D4>D1, D2>D1.

[0018] In some embodiments, the collecting plate further includes a plurality of reinforcing bosses arranged around the annular step, the second welding area is located between each two adjacent reinforcing bosses, and each reinforcing boss is protruded relative to the second welding area in a direction away from the battery cell.

[0019] In some embodiments, there is a gap between a step surface of the annular step facing the battery core and the first electrode tab.

[0020] A battery comprises the battery cell described in any one of the above embodiments.

[0021] An electrical device includes the battery as described in any of the above embodiments, or includes the battery monomer as described in any of the above embodiments.

[0022] In the above-mentioned battery cell, battery, and electrical equipment, the first tab of the battery cell is welded to the second welding area of ​​the current collector, thereby achieving electrical connection with the current collector, and the boss of the first welding area of ​​the current collector is welded to the pole, thereby achieving electrical connection with the pole. That is, the first tab of the battery cell, the current collector, and the pole are electrically connected in sequence, so that the pole serves as an electrode terminal of the battery cell. During assembly, it is necessary to use a laser to perform laser penetration welding on the first tab and the second welding area of ​​the current collector, and on the pole and the boss of the current collector, respectively. Since the thickness of the first welding area of ​​the current collector is greater than the thickness of the second welding area, when the boss of the pole and the first welding area of ​​the current collector is penetrated, the difference between the thickness of the first welding area of ​​the current collector and the thickness of the pole penetrated by the laser is greatly reduced, thereby avoiding the problem of the boss of the current collector being burned through or the laser being unable to penetrate the pole. It can take into account the welding quality of the first tab and the second welding area of ​​the current collector, and the boss of the current collector and the pole, thereby improving the current carrying capacity of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a cross-sectional view of a battery cell in one embodiment of the present application;

[0024] Figure 2 for Figure 1 A partial enlarged view of a battery cell at the pole is shown;

[0025] Figure 3 for Figure 1 A schematic structural diagram of a current collecting plate of a battery cell is shown;

[0026] Figure 4 for Figure 3 A cross-sectional view of the collecting plate shown;

[0027] Figure 5 for Figure 2 A cross-sectional view of a battery cell terminal is shown. DETAILED DESCRIPTION

[0028] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0029] In the description of the present application, it should be understood that 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" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do 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 should not be understood as a limitation on the present application.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0031] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0032] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0033] It should be noted that when 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 an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0034] An embodiment of the present application provides an electrical device that utilizes the following batteries or battery cells as its power source. Specifically, the electrical device may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The vehicle may be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, and the like; the spacecraft includes airplanes, rockets, space shuttles, and spacecraft, and the like; the electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like; the electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, and the like. The embodiment of the present application does not impose any special restrictions on the above-mentioned electrical devices.

[0035] The battery includes a box body and a battery cell, wherein the battery cell is accommodated in the box body. The box body is used to provide a space for accommodating the battery cell. The box body can adopt various structures and shapes, such as a cylinder.

[0036] In a battery, there can be multiple battery cells, and the multiple battery cells can be connected in series, in parallel, or in a mixed connection. Mixed connection means that the multiple battery cells are connected both in series and in parallel. Multiple battery cells can be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells is accommodated in a box; of course, the battery can also be a battery module composed of multiple battery cells first connected in series, in parallel, or in a mixed connection, and the multiple battery modules are then connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in a box. The battery can also include other structures. For example, the battery can also include a busbar component for achieving electrical connection between multiple battery cells. Each battery cell can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to this.

[0037] The specific structure of the battery cell is described in detail below with reference to the accompanying drawings. Figure 1 is a cross-sectional view of a battery cell in an embodiment of the present application; Figure 2 for Figure 1 A partial enlarged view of a battery cell at the pole is shown;

[0038] Figure 3 for Figure 1 A schematic structural diagram of a current collecting plate of a battery cell is shown; Figure 4 for Figure 3 A cross-sectional view of the collecting plate shown; Figure 5 for Figure 2 For ease of description and understanding, the accompanying drawings only show structures relevant to the present application.

[0039] See Figures 1 to 3 As shown, in an embodiment of the present application, a battery cell includes a housing 10, a terminal 20, a battery cell 30, and a current collecting tray 40. The housing 10 has a receiving cavity 11, and the battery cell 30 and the current collecting tray 40 are both received in the receiving cavity 11 of the housing 10. The terminal 20 is mounted on the housing 10, and the battery cell 30 has a first tab (not shown) on the end facing the terminal 20. The current collecting tray 40 is located between the battery cell 30 and the terminal 20. The current collecting tray 40 has a first welding area 41, a second welding area 42 arranged around the first welding area 41, and a transition area 43 located between the first welding area 41 and the second welding area 42. The thickness of the first welding area 41 is greater than that of the second welding area 42. The first welding area 41 is arranged to protrude toward the terminal 20 relative to the second welding area 42, thereby forming a boss 412 on the side of the current collecting tray 40 facing the terminal 20, and a groove 414 on the side of the current collecting tray 40 facing away from the terminal 20. The boss 412 is welded to the pole 20, thereby securing and electrically connecting the collector plate 40 to the pole 20. The second welding region 42 is welded to the first tab of the battery cell 30, thereby securing and electrically connecting the collector plate 40 to the first tab of the battery cell 30. The transition region 43 is formed with an annular step 431 arranged around the boss 412.

[0040] In the above-mentioned battery cell, the first tab of the battery cell 30 is welded to the second welding area 42 of the current collecting disk 40, thereby realizing electrical connection with the current collecting disk 40, and the boss 412 of the first welding area 41 of the current collecting disk 40 is welded to the pole 20, thereby realizing electrical connection with the pole 20, that is, the first tab of the battery cell 30, the current collecting disk 40 and the pole 20 are electrically connected in sequence, so that the pole 20 serves as an electrode terminal of the battery cell. During assembly, it is necessary to use a laser to perform laser penetration welding on the first pole ear and the second welding area 42 of the current collecting plate 40, as well as the pole 20 and the boss 412 of the current collecting plate 40. Since the thickness of the first welding area 41 of the current collecting plate 40 is greater than the thickness of the second welding area 42, when the pole 20 and the boss 412 at the first welding area 41 of the current collecting plate 40 are penetrated by welding, the thickness difference between the thickness of the first welding area 41 of the current collecting plate 40 and the thickness of the laser penetrating the pole 20 is greatly reduced, thereby avoiding the problem of the boss 412 of the current collecting plate 40 being burned through or the laser being unable to penetrate the pole 20. The welding quality between the first pole ear and the second welding area 42 of the current collecting plate 40 and the boss 412 of the current collecting plate 40 and the pole 20 can be taken into account, thereby improving the current carrying capacity of the battery.

[0041] Optionally, the thickness of the first welding region 41 of the collecting disc 40 is 0.4 mm to 0.8 mm, and the thickness of the second welding region 42 of the collecting disc 40 is 0.15 mm to 0.35 mm. Preferably, the thickness of the first welding region 41 of the collecting disc 40 is 0.5 mm, and the thickness of the second welding region 42 of the collecting disc 40 is 0.3 mm.

[0042] It is understood that if the thickness difference between the first welding area 41 and the second welding area 42 of the current collecting plate 40 is too small, the effect of improving welding quality will not be significant. If the thickness difference between the first welding area 41 and the second welding area 42 of the current collecting plate 40 is too large, it will increase processing difficulty, thereby increasing processing costs and reducing yield. To achieve a balance between significantly improving welding quality and reducing processing difficulty, in some embodiments, the thickness difference between the first welding area 41 and the second welding area 42 of the current collecting plate 40 is 0.1mm to 0.4mm, thereby reducing processing difficulty while ensuring significantly improved welding quality.

[0043] It should be noted that because the thickness of the first welding region 41 of the collector plate 40 is greater than the thickness of the second welding region 42, a stamping process is required to form the collector plate 40 having the first welding region 41, the boss 412 of the first welding region 41, and the second welding region 42 by thinning the raw material sheet from a thick layer. For example, if the thickness of the first welding region 41 of the collector plate 40 is 0.5 mm and the thickness of the second welding region 42 of the collector plate 40 is 0.3 mm, a raw material sheet with a thickness of 0.5 mm is selected during the stamping process, and the outer periphery of the raw material sheet is thinned from 0.5 mm to 0.3 mm, thereby forming a second welding region 42 with a thickness of 0.3 mm and a first welding region 41 with a thickness of 0.5 mm.

[0044] Since the raw material sheet material needs to be thinned from a thick stamping process, the strength of the collecting plate 40 may not meet the use requirements, and the collecting plate 40 may crack during the thinning process. To prevent the collecting plate 40 from being too weak and cracking during the thinning process, in this embodiment, a transition area 43 is provided between the first welding area 41 and the second welding area 42. The transition area 43 is formed with an annular step 431 arranged around the boss 412. The annular step 431 is used to strengthen the collecting plate 40, ensuring that the strength of the collecting plate 40 meets the use requirements. The annular step 431 also serves as a buffer for the transition, preventing the collecting plate 40 from cracking during the thinning process.

[0045] Preferably, the first welding region 41, second welding region 42, and transition region 43 of the collector plate 40 are integrally stamped from sheet material of the same thickness. This allows the second welding region 42 to be formed by thinning the sheet material using a stamping process while also stamping the boss 412 in the first welding region 41 and the annular step 431 in the transition region 43. This shortens the process and reduces processing costs.

[0046] See Figures 2 to 5 As shown, in the embodiment of the present application, the side of the pole 20 facing the collecting plate 40 has a first blind hole 21 for accommodating the boss 412. The first blind hole 21, the boss 412, and the annular step 431 are coaxially arranged. The diameter D3 of the first blind hole 21 is larger than the outer diameter D5 of the annular step 431. In this way, since the diameter D3 of the first blind hole 21 is larger than the outer diameter D5 of the annular boss 412, a gap exists between the annular boss 412 and the inner side wall of the first blind hole 21 in the radial direction of the first blind hole 21, thereby ensuring that the boss 412 can be more smoothly inserted into the first blind hole 21 of the pole 20 and is less likely to be offset, thereby reducing the difficulty of assembly.

[0047] Furthermore, the first blind hole 21 includes a bottom wall 211 and a side wall 213 disposed around the bottom wall 211. The boss 412 is inserted into the first blind hole 21, contacting and being welded to the bottom wall 211 of the first blind hole 21. A gap exists between the side wall 213 of the first blind hole 21 and the boss 412, thereby ensuring that the first boss 412 can be smoothly inserted into the first blind hole 21. The depth of the first blind hole 21 is less than the height of the boss 412 protruding from the annular step 431. As a result, only the boss 412 is inserted into the first blind hole 21, while the annular step 431 is not inserted into the first blind hole 21 (i.e., the annular step 431 is located outside the first blind hole 21), which helps to reduce assembly difficulty.

[0048] Furthermore, the diameter of the weld mark formed by welding the boss 412 to the bottom wall 211 of the first blind hole 21 is a preset value D1. The pole 20 has a second blind hole 23 on the side facing away from the collector plate 40, which is coaxial with the first blind hole 21. The diameter D2 of the second blind hole 23 and the outer diameter D4 of the boss 412 satisfy the following conditions: D4>D1, D2>D1. Thus, when welding the pole 20 to the boss 412 of the collector plate 40, the laser enters through the second blind hole 23 of the pole 20, penetrates the pole 20, reaches the first blind hole 21, and forms a weld mark (not shown) between the boss 412 of the collector plate 40 and the bottom wall 211 of the first blind hole 21. Since D4>D1, the surface area where the boss 412 fits with the bottom wall 211 of the first blind hole 21 is large enough to meet the requirement of forming a weld mark with a diameter of the preset value D1 between the boss 412 and the bottom wall 211; since D2>D1, the range covered by the laser that penetrates the pole 20 and reaches the boss 412 is large enough to meet the requirement of forming a weld mark with a diameter of the preset value D1 between the boss 412 and the bottom wall 211.

[0049] Specifically in the embodiment, there is a gap between the step surface of the annular step 431 of the transition area 43 facing the battery cell 30 and the first pole ear of the battery cell 30, so that when the pole 20 and the boss 412 of the collecting plate 40 are through-welded, the heat generated by the welding cannot be directly transferred to the first pole ear of the battery cell 30 through the annular step 431, thereby greatly reducing the heat transferred to the first pole ear of the battery cell 30 and avoiding damage to the first pole ear of the battery cell 30 caused by high temperature.

[0050] Specifically, in this embodiment, the current collecting tray 40 further includes a plurality of reinforcing bosses 44 arranged around the annular step 431. The second welding region 42 of the current collecting tray 40 is located between each two adjacent reinforcing bosses 44, with each reinforcing boss 44 protruding relative to the second welding region 42 and away from the battery cell 30. As a result, due to the thinness and large area of ​​the second welding region 42, the current collecting tray 40 is susceptible to deformation. The provision of the reinforcing bosses 44 reinforces the second welding region 42 of the current collecting tray 40, effectively preventing deformation of the second welding region 42. Furthermore, the protrusion of the reinforcing bosses 44 away from the battery cell 30 prevents the reinforcing bosses 44 from obstructing close contact between the second welding region 42 and the first tab of the battery cell 30. This ensures close contact between the second welding region 42 of the current collecting tray 40 and the first tab of the battery cell 30, further improving the welding quality between the second welding region 42 of the current collecting tray 40 and the first tab of the battery cell 30.

[0051] It should be noted that the transition between the first welding area 41 and the second welding area 42 is not limited to the annular step 431. In other embodiments, a bevel transition can also be used between the first welding area 41 and the second welding area 42, that is, the transition area 43 is set at a certain angle relative to the second welding area 42.

[0052] It is understandable that, when the welding area between the boss 412 and the bottom wall 211 of the first blind hole 21 of the terminal 20 is the same, the gap between the bevel and the sidewall 213 of the first blind hole 21 is smaller in the bevel transition solution, which increases the risk that the boss 412 of the current collecting plate 40 will not fit into the first blind hole 21, seriously affecting the welding quality between the terminal 20 and the boss 412 of the current collecting plate 40. To avoid the situation where the boss 412 cannot fit into the first blind hole 21, one solution is to increase the diameter of the first blind hole 21. However, increasing the diameter of the first blind hole 21 significantly reduces the strength of the terminal 20. Another solution is to reduce the diameter of the boss 412 of the current collecting plate 40. However, reducing the diameter of the boss 412 reduces the welding area between the terminal 20 and the boss 412, thereby significantly weakening the battery's current handling capacity. Therefore, the solution using an annular step 431 for transition can solve the above-mentioned drawbacks of the solution using a bevel transition.

[0053] In an embodiment of the present application, the end of the battery cell 30 that is away from the current collecting disc 40 has a second pole lug (not shown). The second pole lug is electrically connected to the shell 10 through a current collecting component (not shown). For example, the current collecting component is arranged at the end of the battery cell 30 that is away from the current collecting disc 40 and is welded to the second pole lug, and the current collecting component is also welded to the shell 10, so that the second pole lug of the battery cell 30 is electrically connected to the shell 10 through the current collecting component, and then the shell 10 and the pole 20 respectively serve as the two electrode terminals (i.e., the positive pole and the negative pole) of the battery cell, and jointly realize the input and output of electrical energy. It should be noted that the current collecting component is not required. In other embodiments, the second pole lug of the battery cell 30 can also be directly welded to the shell 10, which is not limited here.

[0054] It is understood that either the first or second tab of the battery cell can be a positive tab, while the other can be a negative tab. When the first tab is a positive tab and the second tab is a negative tab, the pole 20 is the positive electrode and the housing 10 is the negative electrode. When the first tab is a negative tab and the second tab is a positive tab, the pole 20 is the negative electrode and the housing 10 is the positive electrode.

[0055] It should be noted that to avoid a short circuit caused by direct electrical connection between the positive and negative electrodes of the battery cell, the electrode 20 needs to be insulated and mounted on the housing 10. That is, the electrode 20 is fixedly mounted on the housing 10 and insulated from the housing 10. Alternatively, the electrode 20 can be riveted to the housing 10, with upper and lower plastics provided between the electrode 20 and the housing 10 for insulation. The riveted structure between the electrode 20 and the housing 10 and the assembly of the upper and lower plastics are relatively mature existing technologies and will not be described in detail here.

[0056] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0057] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A battery cell, characterized in that: include: The housing (10) has a receiving cavity (11); A pole (20) is provided on the housing (10); A battery core (30) is accommodated in the accommodation cavity (11), and one end of the battery core (30) facing the pole (20) has a first pole lug; and A current collecting plate (40) is accommodated in the accommodating cavity (11) and is located between the battery core (30) and the pole (20); the current collecting plate (40) has a first welding area (41), a second welding area (42) arranged around the first welding area (41), and a transition area (43) located between the first welding area (41) and the second welding area (42); the thickness of the first welding area (41) is greater than the thickness of the second welding area (42); The first welding area (41) is arranged to protrude toward the pole (20) relative to the second welding area (42), so as to form a boss (412) on the side of the collecting plate (40) facing the pole (20), and a groove (414) is formed on the side of the collecting plate (40) facing away from the pole (20), the boss (412) is welded to the pole (20), the second welding area (42) is welded to the first pole lug, and the transition area (43) is formed with an annular step (431) arranged around the boss (412).

2. The battery cell according to claim 1, wherein: The thickness of the first welding area (41) is 0.40 mm to 0.80 mm, and the thickness of the second welding area (42) is 0.15 mm to 0.35 mm.

3. The battery cell according to claim 1, wherein: The difference in thickness between the first welding area (41) and the second welding area (42) is 0.1 mm to 0.4 mm.

4. The battery cell according to claim 1, wherein: The first welding area (41), the second welding area (42) and the transition area (43) of the collecting plate (40) are integrally stamped and formed by using plates of the same thickness.

5. The battery cell according to claim 1, characterized in that The pole (20) has a first blind hole (21) on the side facing the collecting plate (40) for accommodating the boss (412), and the first blind hole (21), the boss (412) and the annular step (431) are coaxially arranged; wherein the diameter D3 of the first blind hole (21) is greater than the outer diameter D5 of the annular step (431).

6. The battery cell according to claim 5, characterized in that The first blind hole (21) comprises a bottom wall (211) and a side wall (213) arranged around the bottom wall (211); the boss (412) contacts and is fixed to the bottom wall (211) by welding; and a gap is provided between the side wall (213) and the boss (412); The depth dimension of the first blind hole (21) is smaller than the height dimension of the boss (412) protruding from the annular step (431).

7. The battery cell according to claim 6, characterized in that The diameter of the weld mark formed by welding the boss (412) to the bottom wall (211) is a preset value D1; the pole (20) has a second blind hole (23) coaxial with the first blind hole (21) on a side facing away from the collecting plate (40); the diameter D2 of the second blind hole (23) and the outer diameter D4 of the boss (412) satisfy: D4>D1, D2>D1.

8. The battery cell according to claim 1, wherein: The collecting plate (40) further comprises a plurality of reinforcing bosses (44) arranged around the annular step (431), the second welding area (42) being located between each two adjacent reinforcing bosses (44), and each reinforcing boss (44) being protruded relative to the second welding area (42) in a direction away from the battery cell (30).

9. The battery cell according to claim 1, characterized in that There is a gap between the step surface of the annular step (431) facing the battery core (30) and the first electrode tab.

10. A battery, characterized in that: The battery cell comprises the battery cell according to any one of claims 1 to 9.

11. An electrical device, characterized in that: The method comprises the battery according to claim 10, or comprises the battery cell according to any one of claims 1 to 9.

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