Battery cell, battery and electric device

Abstract

The application relates to a battery monomer, a battery and a power utilization device. The battery monomer comprises a shell with a containing cavity and an opening communicating with the containing cavity; a top cover assembly comprising a top cover, a positive pole column and a negative pole column, the top cover being arranged at the opening of the shell, and the positive pole column and the negative pole column being arranged on the top cover; an electrode assembly comprising an electric core contained in the containing cavity of the shell, the electric core having a positive pole lug and two negative pole lugs on one side surface of the electric core in a first direction and facing the top cover; the positive pole lug and the two negative pole lugs being arranged in a second direction and a third direction; a positive pole adapter plate and a negative pole adapter plate being arranged between the top cover and the electric core, the positive pole adapter plate being connected with the positive pole lug and the positive pole column, and the negative pole adapter plate being connected with the two negative pole lugs and the negative pole column. In this way, the number of lug parts (i.e. one negative pole lug is added) is increased without increasing the number of pole columns, so that the fast charging performance of the battery is improved while the assembly difficulty of the battery is not increased.

Description

Technical Field

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

[0002] The increasing popularity of electric vehicles has led to higher consumer demands for charging speeds. Fast charging can significantly shorten charging time, making the user experience of electric vehicles closer to that of traditional gasoline vehicles, thereby alleviating consumers' range anxiety.

[0003] To improve fast charging performance, battery structure design typically involves increasing the number of tabs to reduce internal resistance, improve overcurrent capacity, and reduce heat generation during charging, thereby enhancing fast charging capability. However, increasing the number of tabs also necessitates increasing the number of terminals. On one hand, the limited space on the battery top cover cannot accommodate too many terminals; on the other hand, an excessive number of terminals increases the difficulty of battery assembly. Utility Model Content

[0004] Therefore, it is necessary to provide a battery cell, battery, and power device that can improve the fast charging performance of the battery without increasing the assembly difficulty of the battery, in order to address the above problems.

[0005] On one hand, this application provides a single battery cell, comprising:

[0006] The housing has a receiving cavity and an opening communicating with the receiving cavity;

[0007] The top cover assembly includes a top cover, a positive terminal, and a negative terminal. The top cover covers the opening of the housing, and the positive terminal and the negative terminal are both disposed on the top cover.

[0008] An electrode assembly includes a battery cell housed within the receiving cavity of the housing. The battery cell has a positive electrode tab and two negative electrode tabs on one side surface facing the top cover in a first direction. The positive electrode tab and the two negative electrode tabs are staggered in a second direction and a third direction, and the first direction, the second direction and the third direction are perpendicular to each other.

[0009] Both the positive and negative adapter pieces are arranged between the top cover and the battery cell. The positive adapter piece is connected to the positive tab and the positive terminal, and the negative adapter piece is connected to the two negative tabs and the negative terminal.

[0010] In some embodiments, the battery cell has a dummy center plane perpendicular to the second direction, the battery cell is divided into a first part and a second part by the dummy center plane, the positive electrode tab is located on the first part, and the two negative electrode tabs are located on the second part; the two negative electrode tabs are located on both sides of the positive electrode tab in the third direction;

[0011] The electrode assembly includes two battery cells stacked along the second direction, with the first portions of the two battery cells facing each other and the second portions of the two battery cells facing away from each other.

[0012] In some embodiments, the positive electrode adapter is connected to the positive electrode lugs and positive electrode posts of the two battery cells, and the negative electrode adapter is connected to the negative electrode lugs and negative electrode posts of the two battery cells.

[0013] In some embodiments, the positive electrode adapter includes two first tab connection portions and a first electrode post connection portion. The two first tab connection portions are arranged at intervals along the second direction and are respectively connected to the positive tab portion of the two battery cells. The first electrode post connection portion is fixedly connected to one end of the two first tab connection portions in the third direction and is connected to the positive electrode post.

[0014] In some embodiments, each of the first tabs has a through hole, and each of the positive tabs includes a first segment and a second segment bent relative to the first segment. The first segment is connected to the side of the battery cell facing the top cover and passes through the through hole on the corresponding first tab. The second segment is attached to and welded to the surface of the first tab facing the top cover.

[0015] In some embodiments, the negative electrode adapter includes two second tab connection portions and a second electrode post connection portion. The two second tab connection portions are spaced apart along the second direction so that a receiving space for accommodating the positive electrode adapter is formed between the two second tab connection portions. Each second tab connection portion is connected to the two negative tab portions of a corresponding cell. The second electrode post connection portion is fixedly connected to one end of the two second tab connection portions in the third direction and is connected to the negative electrode post.

[0016] In some embodiments, each second electrode tab connection includes a first connection sub-part, an intermediate connection sub-part, and a second connection sub-part connected sequentially along the third direction. The first connection sub-part and the second connection sub-part are respectively connected to the two negative electrode tabs on the corresponding battery cell. The end of the second connection sub-part facing away from the intermediate connection sub-part is connected to the second electrode post connection part.

[0017] The receiving space is formed between the intermediate connecting sub-parts of the two second pole ear connectors.

[0018] In some embodiments, each of the negative electrode tabs includes a third segment and a fourth segment bent relative to the third segment, the third segment being connected to the side of the cell facing the top cover, and the fourth segment being attached to and welded to the surface of the corresponding first or second connecting sub-part facing away from the top cover.

[0019] On the other hand, this application provides a battery including a battery cell as described in any of the above embodiments.

[0020] In another aspect, this application provides an electrical device including a battery as described in any of the above embodiments.

[0021] Compared with the prior art, this application has the following beneficial effects:

[0022] The aforementioned battery cell, battery, and electrical device have one positive electrode tab and two negative electrode tabs on the side of the cell facing the top cover. A positive electrode adapter connects the positive electrode tab to the positive terminal, and a negative electrode adapter connects the two negative electrode tabs to the negative terminals. The positive electrode tab and the two negative electrode tabs are staggered in both the second and third directions to facilitate the spatial arrangement of the positive and negative electrode adapters. This ensures that the positive and negative electrode adapters do not come into contact and thus conduct electricity, thereby increasing the number of electrode tabs (i.e., adding one negative electrode tab) without increasing the number of terminals. This improves the battery's fast-charging performance while not increasing the assembly difficulty. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a single battery cell in one embodiment of this application (the casing is omitted);

[0024] Figure 2 for Figure 1 The diagram shows the exploded structure of a single battery cell;

[0025] Figure 3 for Figure 1 A top view of the battery cell shown.

[0026] Figure 4 for Figure 1 The diagram shown is a structural schematic of a single battery cell (the casing and top cover assembly are omitted).

[0027] Figure 5 for Figure 4 A schematic diagram of the electrode assembly of the battery cell shown;

[0028] Figure 6for Figure 4 A top view of the positive electrode adapter of the shown battery cell;

[0029] Figure 7 for Figure 4 The diagram shows a top view of the negative electrode adapter of a single battery cell. Detailed Implementation

[0030] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0031] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0032] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0035] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening 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 possible implementation.

[0036] One embodiment of this application provides an electrical device that uses a battery or battery cell as its power source. Specifically, the electrical device can be a vehicle, mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc. Vehicles can be gasoline-powered vehicles, natural gas-powered vehicles, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc.; spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application embodiment does not impose any special limitations on the above-mentioned electrical device.

[0037] A battery comprises a casing and individual battery cells, which are housed within the casing. The casing provides space for the battery cells and can have various structures and shapes, such as a cuboid. A battery may contain multiple individual cells, which can be connected in series, parallel, or a combination thereof. A combination of series and parallel connections refers to multiple battery cells being connected in both series and parallel configurations. Multiple battery cells can be directly connected in series, parallel, or a combination thereof, and then housed within the casing. Alternatively, multiple battery cells can be first connected in series, parallel, or a combination thereof to form a battery module, and then these modules can be connected in series, parallel, or a combination thereof to form a single unit housed within the casing. The battery may also include other structures, such as a busbar for electrical connection between the multiple battery cells. Each battery cell can be a secondary or primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these.

[0038] The specific structure of the battery cell is described in detail below with reference to the accompanying drawings. Please refer to the attached diagram. Figures 1 to 4 In the embodiments of this application, the battery cell includes a housing, a top cover assembly 10, an electrode assembly 20, a positive electrode adapter 30, and a negative electrode adapter 40. The housing has a receiving cavity and an opening communicating with the receiving cavity. The top cover assembly 10 includes a top cover 11, a positive electrode post 13, and a negative electrode post 15. The top cover 11 covers the opening of the housing to close the opening. Both the positive electrode post 13 and the negative electrode post 15 are disposed on the top cover 11. Specifically, the top cover 11 can be welded and fixed to the end of the housing with the opening, thereby sealing the opening of the housing. The positive electrode post 13 and the top cover 11 can be insulated by providing a plastic component, thus insulating the positive electrode post 13 from the top cover 11; similarly, the negative electrode post 15 and the top cover 11 can also be insulated by providing a plastic component, thus insulating the negative electrode post 15 from the top cover 11.

[0039] The electrode assembly 20 includes a battery cell 21 housed within a housing cavity. The battery cell 21 has a positive electrode lug 23 and two negative electrode lugs 25 on its surface facing the top cover 11 in a first direction X1. The positive electrode lug 23 and the two negative electrode lugs 25 are staggered in both a second direction X2 and a third direction X3. The first direction X1, the second direction X2, and the third direction X3 are perpendicular to each other. A positive electrode adapter 30 and a negative electrode adapter 40 are both disposed between the top cover 11 and the battery cell 21. The positive electrode adapter 30 connects to the positive electrode lug 23 and the positive electrode post 13, such that the positive electrode lug 23 is electrically connected to the positive electrode post 13 via the positive electrode adapter 30. The negative electrode adapter 40 connects to the two negative electrode lugs 25 and the negative electrode post 15, such that the two negative electrode lugs 25 are electrically connected to the negative electrode post 15 via the negative electrode adapter 40.

[0040] The aforementioned battery cell has one positive electrode tab 23 and two negative electrode tabs 25 on the side of the cell 21 facing the top cover 11. A positive electrode adapter 30 connects the positive electrode tab 23 to the positive terminal 13, and a negative electrode adapter 40 connects the two negative electrode tabs 25 to the negative terminal 15. The positive electrode tab 23 and the two negative electrode tabs 25 are staggered in both the second direction X2 and the third direction X3 to facilitate the spatial arrangement of the positive electrode adapter 30 and the negative electrode adapter 40. This ensures that the positive electrode adapter 30 and the negative electrode adapter 40 do not come into contact and thus conduct electricity. This achieves the goal of increasing the number of electrode tabs (i.e., adding one negative electrode tab 25) without increasing the number of terminals, thereby improving the battery's fast-charging performance while not increasing the battery's assembly difficulty.

[0041] In an embodiment of this application, the battery cell 21 has a dummy center plane A perpendicular to the second direction X2. The battery cell 21 is divided into a first part a1 and a second part a2 by the dummy center plane A. The first part a1 of the battery cell 21 has a plurality of positive tabs on one end face facing the top cover 11. The plurality of positive tabs are stacked to form a positive tab portion 23, so the positive tab portion 23 is located on the first part a1. The second part a2 of the battery cell 21 has multiple negative tabs on one end face facing the top cover 11. Multiple negative tabs located on one side of the positive tab 23 in the third direction X3 are stacked to form a negative tab 25, and multiple negative tabs located on the other side of the positive tab 23 in the third direction X3 are stacked to form another negative tab 25. Therefore, the two negative tabs 25 are located on the second part a2, and the two negative tabs 25 are located on both sides of the positive tab 23 in the third direction X3. This makes the positive tab 23 and the two negative tabs 25 staggered in both the second direction X2 and the third direction X3, so as to reduce the spatial arrangement difficulty of the positive adapter 30 and the negative adapter 40.

[0042] Optionally, the battery cell 21 has an end face facing the top cover 11, on which the positive electrode tab 23 and two negative electrode tabs 25 are located. The positive electrode tab 23 is located at the center of the end face in the third direction X3. The two sides of the end face in the third direction X3 are a first edge d1 and a second edge d2, respectively. The two negative electrode tabs 25 are located on both sides of the positive electrode tab 23 in the third direction X3. The negative electrode tab 25 located between the first edge d1 and the positive electrode tab 23 is the first negative electrode tab, and the distance between the first negative electrode tab and the first edge d1 is 10mm to 20mm. The negative electrode tab 25 located between the second edge d2 and the positive electrode tab 23 is the second negative electrode tab, and the distance between the second negative electrode tab and the second edge d2 is also 10mm to 20mm.

[0043] Furthermore, the electrode assembly 20 includes two cells 21, which are stacked along the second direction X2. The first portions a1 of the two cells 21 face each other, and the second portions a2 of the two cells 21 face away from each other, so that the two positive electrode tabs 23 are located approximately in the middle of the area enclosed by the four negative electrode tabs 25, further reducing the spatial arrangement difficulty of the positive electrode adapter 30 and the negative electrode adapter 40.

[0044] Specifically, in this embodiment, the positive electrode adapter 30 is connected to the positive electrode tabs 23 (i.e., the two positive electrode tabs 23) and the positive electrode post 13 of the two battery cells 21, so that the positive electrode tabs 23 of both battery cells 21 are electrically connected to the positive electrode post 13 through the positive electrode adapter 30. The negative electrode adapter 40 is connected to the negative electrode tabs 25 (i.e., the four negative electrode tabs 25) and the negative electrode post 15 of the two battery cells 21, so that the negative electrode tabs 25 of both battery cells 21 are electrically connected to the negative electrode post 15 through the negative electrode adapter 40. In this way, all positive electrode tabs 23 are electrically connected to the positive electrode post 13 using one positive electrode adapter 30, and all negative electrode tabs 25 are electrically connected to the negative electrode post 15 using one negative electrode adapter 40, without increasing the number of adapters, thus without increasing the assembly difficulty.

[0045] Please see Figures 4 to 6 Specifically, in this embodiment, the positive electrode adapter 30 includes two first tab connection portions 31 and a first terminal connection portion 32. The two first tab connection portions 31 are spaced apart along a second direction X2 and are respectively connected to the positive tab portions 23 (i.e., the two positive tab portions 23) on the two battery cells 21. The first terminal connection portion 32 is fixedly connected to one end of the two first tab connection portions 31 in a third direction X3 and is connected to the positive terminal 13. Thus, by connecting the first terminal connection portion 32 of the positive electrode adapter 30 to the positive terminal 13, and by connecting the two first tab connection portions 31 of the positive electrode adapter 30 to the two positive tab portions 23 respectively, the two positive tab portions 23 are electrically connected to the positive terminal 13 through the positive electrode adapter 30. Optionally, the first tab connection portions 31 and the positive tab portions 23 can be connected by welding. The first terminal connection portion 32 and the positive terminal 13 can also be connected by welding.

[0046] Specifically, the two first tab connection portions 31 and the first pole post connection portion 32 of the positive electrode adapter 30 are integrally formed, for example, by stamping process.

[0047] Optionally, the width of the positive electrode adapter 30 in the second direction X2 can be 20mm to 50mm, and the length of the positive electrode adapter 30 in the third direction X3 can be 40mm to 80mm.

[0048] Furthermore, each first tab connection portion 31 is provided with a through hole 311, and each positive tab portion 23 includes a first segment 231 and a second segment 233 bent relative to the first segment 231. The first segment 231 of the positive tab portion 23 is connected to the side of the cell 21 facing the top cover 11 and passes through the through hole 311 on the corresponding first tab connection portion 31. The second segment 233 of the positive tab portion 23 is attached to and welded to the surface of the first tab connection portion 31 facing the top cover 11. In this way, by passing the positive tab portion 23 through the through hole 311 on the first tab connection portion 31, the second segment 233 of the positive tab portion 23 is located on the side of the first tab connection portion 31 facing the top cover 11. This facilitates welding the second segment 233 of the positive tab portion 23 to the first tab connection portion 31, greatly reducing the welding difficulty; on the other hand, it greatly reduces the pressure and bending of the positive tab portion 23 by the positive adapter piece 30.

[0049] Please see Figure 4 , Figure 5 and Figure 7 Specifically, in this embodiment, the negative electrode adapter 40 includes two second electrode tab connection portions 41 and a second electrode post connection portion 42. The two second electrode tab connection portions 41 are spaced apart along a second direction X2, so that a receiving space B for accommodating the positive electrode adapter 30 is formed between the two second electrode tab connection portions 41. That is, the positive electrode adapter 30 is arranged between the two second electrode tab connection portions 41 of the negative electrode adapter 40. Each second electrode tab connection portion 41 is connected to the two negative electrode tab portions 25 of a corresponding cell 21, and the second electrode post connection portion 42 is fixedly connected to one end of the two second electrode tab connection portions 41 in a third direction X3 and is connected to the negative electrode post 15. Thus, the second electrode connection portion 42 of the negative electrode adapter 40 is connected to the negative electrode post 15, and the two second electrode tab connection portions 41 of the negative electrode adapter 40 are respectively connected to the negative electrode tabs 25 of the two battery cells 21, thereby achieving an electrical connection between the negative electrode tabs 25 of the two battery cells 21 and the negative electrode post 15 through the negative electrode adapter 40. Optionally, the second electrode tab connection portion 41 and the negative electrode tab 25 can be connected by welding. The second electrode connection portion 42 and the negative electrode post 15 can also be connected by welding.

[0050] Specifically, the two second electrode tab connection portions 41 and the second electrode post connection portion 42 of the negative electrode adapter 40 are integrally formed, for example, by stamping process.

[0051] Furthermore, each second electrode tab connection portion 41 includes a first connecting sub-portion 411, an intermediate connecting sub-portion 412, and a second connecting sub-portion 413 connected sequentially along a third direction X3. The first connecting sub-portion 411 and the second connecting sub-portion 413 are respectively connected to the two negative electrode tabs 25 on the corresponding battery cell 21. The end of the second connecting sub-portion 413 facing away from the intermediate connecting sub-portion 412 is fixedly connected to the second electrode post connection portion 42. The intermediate connecting sub-portions 412 of the two second electrode tab connection portions 41 form the aforementioned receiving space B, that is, the aforementioned positive electrode adapter 30 is arranged between the two intermediate connecting sub-portions 412. In this way, it is ensured that the positive electrode adapter 30 realizes the electrical connection between the two positive electrode tabs 23 and the positive electrode post 13, and the negative electrode adapter 40 realizes the electrical connection between the four negative electrode tabs 25 and the negative electrode post 15, while also ensuring that the positive electrode adapter 30 and the negative electrode adapter 40 do not interfere with each other or come into contact with each other.

[0052] Optionally, the negative electrode adapter 40 has a length of 90 mm to 240 mm in the third direction X3. The negative electrode adapter 40 has a width of 26 mm to 60 mm in the second direction X2. The intermediate connecting sub-part 412 has a length of 50 mm to 90 mm in the third direction X3. The spacing between the two intermediate connecting sub-parts 412 is 24 mm to 54 mm.

[0053] Furthermore, each negative electrode tab 25 includes a third segment 251 and a fourth segment 253 bent relative to the third segment 251. The third segment 251 of the negative electrode tab 25 is connected to the side of the cell 21 facing the top cover 11, and the fourth segment 253 of the negative electrode tab 25 is attached to and welded to the corresponding first connecting part 411 or second connecting part 413 on the side facing away from the top cover 11. In this way, the second segment 233 of the positive electrode tab 23 is welded to the side of the first electrode tab connection 31 of the positive electrode adapter 30 facing the top cover 11, and the fourth segment 253 of the negative electrode tab 25 is welded to the side of the first connecting part 411 or second connecting part 413 of the negative electrode adapter 40 on the side facing away from the top cover 11, thereby making the positive electrode adapter 30 and the negative electrode adapter 40 have a height difference in the first direction X1, further ensuring that the positive electrode adapter 30 and the negative electrode adapter 40 are isolated and prevent them from contacting and conducting electricity.

[0054] The beneficial effects of the battery cell in this application will be illustrated below by comparing Example 1 and Comparative Example 1:

[0055] Example 1 uses the battery cell described in this application (i.e., a cell comprising one positive electrode and two negative electrode tabs), and performs battery energy density testing, rate performance testing, and cycle performance testing on this battery cell. Comparative Example 1 uses a battery cell from the prior art (i.e., a cell comprising one positive electrode and one negative electrode tab), and performs the same battery energy density testing, rate performance testing, and cycle performance testing as in Example 1. In other words, Example 1 and Comparative Example 1 are identical except for the structure of the battery cell used.

[0056] Specifically, the battery energy density testing steps are as follows: 1) Weigh the battery cell to obtain its weight m; 2) At 25℃, charge the battery cell at a constant current of 0.33C to 3.65V, then charge it at a constant voltage of 3.65V until the current ≤ 0.05C. After standing for 5 minutes, discharge it at a constant current of 0.33C to 2.0V to obtain the discharge energy Q; 3) Obtain the energy density of the battery cell based on Q / m.

[0057] The rate performance test steps are as follows: Step 1, 1 / 3C0 capacity calibration procedure: Let stand at room temperature for 5 minutes, charge at 1 / 3C constant current to 3.65V, then charge at 3.65V constant voltage until the current ≤0.05C, let stand for 5 minutes, then discharge at 1 / 3C to 2.0V, repeat 2 to 5 times to obtain the standard capacity C0 (take the capacity of the second cycle as the standard); Step 2, DC / CC-Rate test procedure: 1) Let stand at 25℃ for 5 minutes; 2) Discharge at 1 / 3C0 to 2.0V; 3) Let stand for 30 minutes; 4) Charge at 1 / 3C0 constant current to 3.65V, then charge at constant voltage until I≤0.05C0; 5) Let stand for 30 minutes; 6) Discharge at XC0 to 2.0V; 7) Let stand for 60 minutes; 8) Discharge at 1 / 3C0 to 2.0V;

[0058] 9) Let stand for 30 min; 10) Charge at a constant current of XC0 to 3.65V, then charge at a constant voltage until I≤0.05C0; 11) Let stand for 60 min; 12) Repeat steps 2) to 11) with X successively at 4C and 5C to obtain the charge and discharge capacity of the battery cells at different rates; 13) Extract the constant current charging capacity from step 10) to calculate the charge capacity retention rate, and extract the constant current ratio at each rate.

[0059] The battery cycle performance test procedure is as follows: At 25℃, the battery cell is charged at a constant current of 0.33C to a voltage of 3.65V, and then charged at a constant voltage to a current of 0.05C; after resting for 5 minutes, it is discharged at 1 / 3C to 2.0V; after resting for 5 minutes, the discharge capacity at this time is recorded, which is the discharge capacity C0 of the first cycle. The battery is discharged at XC to 2.0V; after resting for 30 minutes, it is charged at 0.5C to 3.65V; after resting for 30 minutes, it is discharged at XC to 2.0V; after resting for 30 minutes, it is discharged at XC to 2.0V; after resting for 30 minutes, the above steps are repeated with X as 4C and 5C respectively, and the capacity at the 300th cycle is recorded as C. The capacity retention rate after 300 cycles is obtained by using the formula C / C0*100%.

[0060] Table 1: Experimental data of Example 1 and Comparative Example 1

[0061]

[0062] The experimental results of Example 1 and Comparative Example 1 are shown in Table 1. As can be seen from Table 1, the constant current ratio during charging and the capacity retention rate during discharging at high rates of 4C and 5C in Example 1 are both greater than those in Comparative Example 1. This indicates that the fast charging performance of the battery cell (with one positive tab and two negative tabs) in Example 1 is significantly improved compared to the battery cell (with one positive tab and one negative tab) in Comparative Example 1.

[0063] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above 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.

[0064] The embodiments described above are merely illustrative of several implementation methods of this application, and 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 those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A battery cell, characterized in that, include: The housing has a receiving cavity and an opening communicating with the receiving cavity; The top cover assembly (10) includes a top cover (11), a positive terminal (13) and a negative terminal (15). The top cover (11) covers the opening of the housing, and the positive terminal (13) and the negative terminal (15) are both disposed on the top cover (11). The electrode assembly (20) includes a battery cell (21) housed within the receiving cavity of the housing. The battery cell (21) has a positive electrode tab (23) and two negative electrode tabs (25) on the side surface facing the top cover (11) in a first direction (X1). The positive electrode tab (23) and the two negative electrode tabs (25) are staggered in a second direction (X2) and a third direction (X3), and the first direction (X1), the second direction (X2), and the third direction (X3) are perpendicular to each other. The positive electrode adapter (30) and the negative electrode adapter (40) are both arranged between the top cover (11) and the battery cell (21). The positive electrode adapter (30) is connected to the positive electrode lug (23) and the positive electrode post (13). The negative electrode adapter (40) is connected to the two negative electrode lugs (25) and the negative electrode post (15).

2. The battery cell according to claim 1, characterized in that, The battery cell (21) has a dummy center plane (A) perpendicular to the second direction (X2). The battery cell (21) is divided into a first part (a1) and a second part (a2) by the dummy center plane (A). The positive electrode tab (23) is located on the first part (a1), and the two negative electrode tabs (25) are located on the second part (a2). The two negative electrode tabs (25) are located on both sides of the positive electrode tab (23) in the third direction (X3). The electrode assembly (20) includes two cells (21) stacked along the second direction (X2), with the first portions (a1) of the two cells (21) facing each other and the second portions (a2) of the two cells (21) facing away from each other.

3. The battery cell according to claim 2, characterized in that, The positive electrode adapter (30) is connected to the positive electrode lug (23) and the positive electrode post (13) of the two cells (21), and the negative electrode adapter (40) is connected to the negative electrode lug (25) and the negative electrode post (15) of the two cells (21).

4. The battery cell according to claim 2, characterized in that, The positive electrode adapter (30) includes two first electrode tab connection portions (31) and a first electrode post connection portion (32). The two first electrode tab connection portions (31) are arranged at intervals along the second direction (X2) and are respectively connected to the positive electrode tab portion (23) of the two cells (21). The first electrode post connection portion (32) is fixedly connected to one end of the two first electrode tab connection portions (31) in the third direction (X3) and is connected to the positive electrode post (13).

5. The battery cell according to claim 4, characterized in that, Each of the first electrode tab connection portions (31) is provided with a through hole (311), and each of the positive electrode tab portions (23) includes a first segment (231) and a second segment (233) bent relative to the first segment (231). The first segment (231) is connected to the side of the battery cell (21) facing the top cover (11) and passes through the through hole (311) on the corresponding first electrode tab connection portion (31). The second segment (233) is attached to and welded to the surface of the first electrode tab connection portion (31) facing the top cover (11).

6. The battery cell according to claim 2, characterized in that, The negative electrode adapter (40) includes two second electrode tabs (41) and a second electrode post (42). The two second electrode tabs (41) are arranged at intervals along the second direction (X2) so that a receiving space (B) for accommodating the positive electrode adapter (30) is formed between the two second electrode tabs (41). Each second electrode tab (41) is connected to the two negative electrode tabs (25) of a corresponding cell (21). The second electrode post (42) is fixedly connected to one end of the two second electrode tabs (41) in the third direction (X3) and is connected to the negative electrode post (15).

7. The battery cell according to claim 6, characterized in that, Each second electrode tab connection portion (41) includes a first connection sub-portion (411), an intermediate connection sub-portion (412), and a second connection sub-portion (413) connected sequentially along the third direction (X3). The first connection sub-portion (411) and the second connection sub-portion (413) are respectively connected to the two negative electrode tabs (25) on the corresponding battery cell (21). The end of the second connection sub-portion (413) opposite to the intermediate connection sub-portion (412) is connected to the second electrode post connection portion (42). The receiving space (B) is formed between the intermediate connecting sub-parts (412) of the two second pole ear connecting parts (41).

8. The battery cell according to claim 7, characterized in that, Each of the negative electrode tabs (25) includes a third segment (251) and a fourth segment (253) bent relative to the third segment (251). The third segment (251) is connected to the side of the cell (21) facing the top cover (11), and the fourth segment (253) is attached to and welded to the surface of the corresponding first connecting sub-part (411) or second connecting sub-part (413) away from the top cover (11).

9. A battery, characterized in that, Includes the battery cell as described in any one of claims 1 to 8.

10. An electrical device, characterized in that, Includes the battery as described in claim 9.

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