Single battery, battery pack and electric device
By setting multiple tabs on the electrode sheet and directly welding them to the electrode post, the problems of low battery energy density and process efficiency in the existing technology are solved, achieving higher energy density and lower manufacturing cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2026-03-31
AI Technical Summary
In existing square aluminum-cased batteries, the welding processes of the tabs and adapters, as well as the welding of the adapters and terminals, are cumbersome, resulting in reduced battery energy density and low process efficiency.
Multiple tabs are set on the electrode sheet. The tabs are stacked along the first direction and bent toward the center of the cell. They are directly welded to the terminal post, eliminating the need for adapter plates, reducing welding processes, and improving space utilization.
This improves the energy density and process efficiency of individual cells while reducing manufacturing costs.
Smart Images
Figure CN224067857U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery technology, specifically to a single cell, a battery pack, and an electrical device. Background Technology
[0002] Currently, new energy vehicles are emerging worldwide, and high-performance lithium-ion power batteries with high specific energy, high specific power, and long lifespan are being widely used in pure electric vehicles and hybrid vehicles. Due to their superior performance in energy density, lightweight design, and heat dissipation, square aluminum-cased batteries have become an ideal power source choice in the field of power batteries.
[0003] In current square aluminum-cased batteries, the tabs of the cells are typically connected to the terminals on the top cover via adapter plates. These adapter plates occupy internal space, reducing the battery's energy density to some extent. Furthermore, the welding between the tabs and the adapter plates, as well as the welding between the adapter plates and the terminals, makes the process cumbersome and affects manufacturing efficiency. Utility Model Content
[0004] This application provides a single-cell battery, a battery pack, and an electrical device, which are beneficial for improving the energy density of the single-cell battery and the manufacturing efficiency of the single-cell battery.
[0005] Specifically, this application provides a single-cell battery. The single-cell battery includes: a casing; a top cover, which covers the casing and forms a receiving cavity with the casing; a terminal post, fixed to the top cover and passing through the top cover; and a cell, disposed in the receiving cavity, and the cell includes an electrode sheet and a separator; the single-cell battery has a first direction Y, the electrode sheet includes an electrode sheet body and multiple tabs connecting the electrode sheet body; the multiple tabs are stacked along the first direction Y, forming a tab bundle located on the side of the electrode sheet body facing the top cover, the tab bundle being welded to one end of the terminal post facing the cell; in the first direction Y, the flattened length of each tab increases sequentially from the center of the cell towards both sides of the cell, and each tab is bent towards the center of the cell; in the first direction Y, the tabs are sequentially numbered 1, 2, 3…N along the direction from the center of the cell towards one side of the cell, and the flattened length of the i-th tab is H. i mm, where i is 1, 2, 3…N, satisfying: H i =H1+(i-1)D; The electrode includes a positive electrode and a negative electrode, where D represents the sum of the thickness of one positive electrode, the thickness of one negative electrode, and the thickness of the two separators.
[0006] In one embodiment of this application, in the first direction Y, the tab bundle includes a first tab bundle disposed in the middle of the cell facing one side of the cell, and a second tab bundle disposed in the middle of the cell facing the other side of the cell; the single cell also has a second direction X and a third direction Z, the first direction Y, the second direction X and the third direction Z intersect each other, and the cell and the top cover are disposed opposite each other along the third direction Z; in the second direction X, the first tab bundle and the second tab bundle are distributed at intervals.
[0007] In one embodiment of this application, the battery cell is a wound battery cell, with one end of the electrode body being the winding end, and the electrode body being wound around the winding end; along a first direction, the electrode body includes layers 1, 2, 3...N sequentially from the inside out; when the electrode is in a flattened state, the tabs of the first tab bundle and the tabs of the second tab bundle are alternately distributed in a direction away from the winding end; and when the electrode is in a flattened state, in the direction from the winding end to the winding end, the distance between the i-th tab of the first tab bundle and the i-th tab of the second tab bundle is L. i mm, where i is 1, 2, 3…N; satisfying: L i =L1+(i-1)πD.
[0008] In one embodiment of this application, when the electrode sheet is in a flattened state, the distance between the nth electrode of the second electrode bundle and the (n+1)th electrode of the first electrode bundle in the direction away from the winding end is M. n mm, where n is 1, 2, 3…N-1; satisfying: M n =M1+(n-1)πD.
[0009] In one embodiment of this application, in a first direction, the flattened length H1 mm of the first tab satisfies: 4≤H1≤8; and / or, in the direction from the winding end to the winding end, the distance L1 mm between the first tab of the first tab bundle and the first tab of the second tab bundle satisfies: 20≤L1≤30; and / or, in the direction away from the winding end, the distance M1 mm between the first tab of the second tab bundle and the second tab of the first tab bundle satisfies: 100≤M1≤200.
[0010] In one embodiment of this application, the battery cell further includes two bent portions and two connecting portions. The two bent portions are spaced apart along a second direction X, and the two connecting portions are spaced apart along a first direction Y. In the circumferential direction of the battery cell, each bent portion and each connecting portion are alternately connected. The connecting portions extend along the second direction X. The tabs of the first tab bundle and the tabs of the second tab bundle are both connected to the connecting portions.
[0011] In one embodiment of this application, the tabs of the first tab bundle are connected to one of the two connecting portions, and the tabs of the second tab bundle are connected to the other of the two connecting portions.
[0012] In one embodiment of this application, the electrode includes a positive electrode and a negative electrode, the first electrode bundle includes a first positive electrode bundle and a first negative electrode bundle, and the second electrode bundle includes a second positive electrode bundle and a second negative electrode bundle; the electrodes of the first positive electrode bundle and the electrodes of the second positive electrode bundle are connected to the electrode body of the positive electrode; the electrodes of the first negative electrode bundle and the electrodes of the second negative electrode bundle are connected to the electrode body of the negative electrode.
[0013] Accordingly, this application also provides a battery pack, including a housing and a single battery cell as described above, wherein the single battery cell is disposed in the housing.
[0014] Accordingly, this application also provides an electrical device, including the battery pack described above, wherein the battery pack is a power supply for the electrical device.
[0015] The beneficial effects of this application are as follows: Unlike existing technologies, this application provides a single-cell battery, a battery pack, and an electrical device. In this single-cell battery, the electrode of the cell includes an electrode body and multiple tabs connecting to the electrode body. These tabs can be wound to form a tab bundle located on the side of the electrode body facing the top cover. In the tab bundle, each tab is stacked along a first direction, and each tab is bent towards the center of the cell, allowing the end of each tab near the center of the cell to be directly welded to the terminal post. In other words, this application eliminates the need for adapter plates; instead, the tabs are directly welded to the terminal post, avoiding the adapter plates occupying internal space of the single-cell battery, which is beneficial for improving the energy density of the single-cell battery. Furthermore, it reduces welding processes, which is beneficial for improving the manufacturing efficiency of the single-cell battery.
[0016] Furthermore, compared to a design where the flattened length of each tab remains constant, the flattened length of each tab in this application increases progressively from the center of the cell towards both sides of the cell. That is, the flattened length of the tabs near the center of the cell is smaller, which can reduce the amount of foil material used and help reduce the manufacturing cost of a single cell. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.
[0018] Figure 1 This is a schematic diagram of the structure of a single battery cell according to an embodiment of this application;
[0019] Figure 2 This is a cross-sectional structural schematic diagram of a single cell embodiment of the present application;
[0020] Figure 3This is a top view of one embodiment of the battery cell of this application;
[0021] Figure 4 yes Figure 3 A partial schematic diagram of a cross-sectional structure of the battery cell along the AA direction in one embodiment.
[0022] Figure 5 yes Figure 4 The diagram shows the structure of region B of the battery cell.
[0023] Figure 6 This is a schematic diagram of an embodiment of the electrode sheet in a flattened state according to this application.
[0024] Explanation of reference numerals in the attached figures:
[0025] 10 Single cell; 11 Casing; 12 Top cover; 13 Terminal post; 131 Positive terminal post; 132 Negative terminal post; 14 Receiving cavity; 20 Cell; 22 Electrode; 221 Positive electrode; 222 Negative electrode; 223 Winding end; 224 Electrode body; 225 Winding end; 23 Separator; 24 Tab bundle; 241 First tab bundle; 241a First positive tab bundle; 241b First negative tab bundle; 242 Second tab bundle; 242a Second positive tab bundle; 242b Second negative tab bundle; 243 Tab; 25 Bending portion; 26 Connecting portion. Detailed Implementation
[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "up," "down," "left," and "right" generally refer to up, down, left, and right in the actual use or working state of the device, specifically the drawing directions in the accompanying drawings.
[0027] In this application, unless otherwise expressly specified and limited, the terms "connected," "linked," "stacked," 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 direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0028] This application provides a single battery cell, a battery pack, and an electrical device, which are described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments of this application. Furthermore, the descriptions of each embodiment have their own emphasis; parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments.
[0029] To address the technical problems of low energy density and low process efficiency in existing single-cell batteries, an embodiment of this application provides a single-cell battery. This is described in detail below.
[0030] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a single battery cell according to an embodiment of this application.
[0031] In one embodiment, the battery pack includes a housing and a plurality of individual battery cells 10 housed within the housing. The individual battery cells 10 include, but are not limited to, lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and this disclosure does not limit the specific types. The battery pack provides power to an electrical device. The electrical device can be a mobile phone, portable device, laptop computer, electric vehicle, electric car, ship, spacecraft, electric toy, or power tool, etc. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys; 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.
[0032] The following describes the single-cell battery 10 of the present application.
[0033] Please refer to the following: Figures 2 to 5 , Figure 2 This is a cross-sectional structural schematic diagram of a single cell embodiment of the present application. Figure 3 This is a top view schematic diagram of an embodiment of the battery cell of this application. Figure 4 yes Figure 3 The diagram shows a partial schematic of a cross-sectional structure of the battery cell along the AA direction in one embodiment. Figure 5 yes Figure 4 The diagram shows the structure of region B of the battery cell.
[0034] The single battery cell 10 has a first direction Y, a second direction X, and a third direction Z. The first direction Y, the second direction X, and the third direction Z intersect each other in pairs. The cell 20 and the top cover 12 are arranged opposite each other along the third direction Z. It should be understood that the introduction of the intersecting first direction X, second direction Y, and third direction Z is to more clearly describe and illustrate the three-dimensional structure of the single battery cell 10, battery pack, or electrical device in the specific solutions provided in the various embodiments of this application, as well as the position and connection relationship between the components, and should not be considered as constituting any substantial limitation on the technical solution protected by this application. For those skilled in the art, the intersecting directions can be understood as the first direction X, the second direction Y, and the third direction Z being perpendicular to each other, or almost perpendicular to each other, or having an angle greater than 85° between them. Those skilled in the art can make various modifications and variations without departing from the spirit and scope of this utility model. Such modifications and variations all fall within the scope defined by the appended claims, even if the first direction X, the second direction Y, and the third direction Z are not strictly orthogonal in these modifications and variations.
[0035] In one embodiment, the single battery cell 10 includes a housing 11. The single battery cell 10 also includes a top cover 12, which covers the housing 11 and forms a receiving cavity 14 with the housing 11. The single battery cell 10 also includes an electrode post 13, which is fixed to and passes through the top cover 12. The single battery cell 10 also includes a battery cell 20, disposed in the receiving cavity 14, and the battery cell 20 includes an electrode 22 and a separator 23; the single battery cell 10 also includes a battery cell 20, disposed in the receiving cavity 14, and the battery cell 20 is electrically connected to the electrode post 13.
[0036] In the first direction Y, the electrode 22 includes an electrode body 224 and a plurality of tabs 243 connected to the electrode body 224; the plurality of tabs 243 are stacked along the first direction Y and form a tab bundle 24 located on the side of the electrode body 224 facing the top cover 12, and the tab bundle 24 is welded to the end of the electrode post 13 facing the cell 20; in the first direction Y, the flattened length of each tab 243 increases gradually from the middle of the cell 20 toward both sides of the cell 20, and each tab 243 is bent toward the middle of the cell 20.
[0037] Specifically, the battery cell 20 includes an electrode 22 and a separator 23, which are stacked and wound to form the battery cell 20. The electrode 22 includes an electrode body 224 and a plurality of tabs 243 connected to the electrode body 224; the electrode body 224 and the separator 23 are stacked and wound in sequence, and the plurality of tabs 243 can form a tab bundle 24 on the side of the electrode body 224 facing the top cover 12 after winding, and the tab bundle 24 is welded to one end of the electrode post 13 located in the receiving cavity 14.
[0038] For ease of description, each embodiment of this application uses a single battery cell employing a wound cell 20 as an example to describe the technical solutions claimed in this application. However, it should be understood by those skilled in the art that the single battery cell 10 provided in some embodiments and solutions of this application, even if it employs a stacked cell 20, can still achieve the technical effects of the technical solutions sought to be protected by the independent claims of this application. Any modifications or variations made by those skilled in the art to the type of cell 20, such as changing it to a stacked cell 20, without departing from the spirit and scope of this utility model, should be considered to fall within the scope defined by the appended claims.
[0039] In the tab bundle 24, each tab 243 is arranged sequentially from the middle of the cell 20 toward the outside of the cell 20. The flattened length of each tab 243 increases progressively from the middle of the cell 20 toward the outside of the cell 20. Each tab 243 is bent toward the middle of the cell 20, and the end of each tab 243 near the middle of the cell 20 is directly welded to the terminal post 13. In this single battery cell 10, the electrode 22 of the cell 20 includes an electrode body 224 and a plurality of tabs 243 connecting the electrode body 224. These plurality of tabs 243 can form a tab bundle 24 located on the side of the electrode body 224 facing the top cover 12 after winding.
[0040] Electrode 22 is made by coating an active material onto a foil. Electrode 22 and separator 23 are wound together to form a battery cell 20. The resulting battery cell 20 is assembled into a casing through a series of processes, and finally activated by injecting electrolyte. In the prior art, multiple equal-height tabs are cut from the reserved area at the edge of the foil using laser die-cutting, with a certain gap between adjacent tabs. The die-cut positive and negative electrode sheets are separated by a separator and wound together with tabs on the same side to obtain the battery cell. Positive tabs are stacked to form a positive tab bundle, and negative tabs are stacked to form a negative tab bundle. After the battery cell is assembled into the casing, the positive and negative tab bundles are bent and attached to the adapter plate. Then, the positive and negative tab bundles are welded to the adapter plate by ultrasonic welding to achieve electrical conduction between the tabs and the adapter plate. Finally, the top cover with positive and negative posts is welded to the adapter plate by laser welding. Existing technologies using adapter plates occupy the internal space of individual cells, which reduces the energy density of individual cells to some extent. Furthermore, multiple welding processes make the process cumbersome and affect manufacturing efficiency.
[0041] In this embodiment, multiple tabs 243 are stacked along the first direction Y. Specifically, each tab 243 is arranged sequentially from the middle of the cell 20 toward the outside of the cell 20, and each tab 243 is bent toward the middle of the cell 20, so that the end of each tab 243 near the middle of the cell 20 can be directly welded to the terminal post 13. In other words, this embodiment eliminates the adapter piece, and instead the tabs 243 are directly welded to the terminal post 13, which avoids the adapter piece occupying the internal space of the single cell 10, which is beneficial to improving the energy density of the single cell 10. Furthermore, this embodiment reduces the original two welding processes between the tab 243 and the adapter piece and between the adapter piece and the terminal post 13 to a single welding process between the tab 243 and the terminal post 13, which is beneficial to improving the process efficiency of the single cell 10. Furthermore, compared to the design where the flattened length of each tab 243 is consistent, in this embodiment, the flattened length of each tab 243 increases gradually from the middle of the cell 20 toward the outside of the cell 20. That is, the flattened length of the tab 243 near the middle of the cell 20 is smaller, which can reduce the amount of foil material used and help reduce the manufacturing cost of the single cell 10.
[0042] It should be noted that in this embodiment, the flattened length of each tab 243 increases progressively from the center of the cell 20 towards both sides of the cell 20, and also progressively from the center of the cell 20 towards the outside of the cell 20. This makes the ends of each tab 243 near the center of the cell 20 relatively flush after bending, which is beneficial for improving the space utilization of the receiving cavity 14 and facilitating the arrangement of the cell 20 in the receiving cavity 14. The single cell 10 has a third direction Z, and the top cover 12 is placed on the end of the housing 11 in the third direction Z. The cell 20 and the top cover 12 are arranged opposite each other in the third direction Z. The flattened length of the tab 243 should be understood as the size of the tab 243 in the third direction Z after it is flattened along the third direction Z.
[0043] In one embodiment, the electrode 22 includes a positive electrode 221 and a negative electrode 222, which are separated by a separator 23. The positive electrode 221, negative electrode 222, and separator 23 are stacked and wound to form a cell 20. Both the positive electrode 221 and the negative electrode 222 include an electrode body 224 and a plurality of tabs 243 connecting the electrode body 224. The plurality of tabs 243 of the positive electrode 221 can form a positive tab bundle after winding, and the plurality of tabs 243 of the negative electrode 222 can form a negative tab bundle after winding. Therefore, the polarity of each tab 243 in the same tab bundle 24 is the same. The single cell 10 also has a second direction X perpendicular to the third direction Z. The terminal post 13 includes a positive terminal post 13 and a negative terminal post 13, which are spaced apart along the second direction X. The ends of the tabs 243 on the positive electrode 221 that are close to the middle of the cell 20 are directly welded to the positive electrode post 13, and the ends of the tabs 243 on the negative electrode 222 that are close to the middle of the cell 20 are directly welded to the negative electrode post 13.
[0044] It should be noted that the tab bundle 24 mentioned below can be a positive tab bundle or a negative tab bundle. That is, the tabs 243 of the positive tab bundle and the tabs 243 of the negative tab bundle in the embodiments of this application both satisfy the following rules.
[0045] Please refer to the following: Figure 6 , Figure 6 This is a schematic diagram of an embodiment of the electrode sheet in a flattened state according to this application.
[0046] In one embodiment, in the first direction Y, the tabs 243 are sequentially numbered 1, 2, 3...N along the direction from the middle of the cell 20 toward one side of the cell 20, and the flattened length of the i-th tab 243 is H. i mm, where i is 1, 2, 3…N, satisfying: H i =H1+(i-1)D; The electrode 22 includes a positive electrode 221 and a negative electrode 222, where D represents the sum of the thickness of one layer of positive electrode 221, the thickness of one layer of negative electrode 222, and the thickness of the two layers of separator 23. That is, in the tab bundle 24, each tab 243 is sequentially numbered along the direction from the middle of the cell 20 toward the outside of the cell 20, the total number of tabs 243 is N, and the flattened length of each tab 243 is H. i mm, where i is 1, 2, 3…N; the difference in flattened length between any two adjacent tabs 243 is D mm, where D is the sum of the thickness of one layer of positive electrode 221 (i.e., the thickness of the electrode body 224 of the positive electrode 221), the thickness of one layer of negative electrode 222 (i.e., the thickness of the electrode body 224 of the negative electrode 222), and the thickness of the two layers of separator 23, satisfying: H i =H1+(i-1)D. H1 satisfies: 4≤H1≤8, for example, H1 can be any value among 4, 5, 6, 7, and 8.
[0047] In this embodiment, by reasonably setting the flattened length of each tab 243 in the same tab bundle 24, it is further beneficial to ensure that the ends of each tab 243 in the tab bundle 24 near the middle of the cell 20 are relatively flush after bending, which is beneficial to improving the space utilization of the receiving cavity 14 and facilitating the arrangement of the cell 20 in the receiving cavity 14. Figure 5 Taking the negative electrode sheet 222 as an example, the tabs 243 of the negative electrode bundle are all bent towards the middle of the cell 20, and the tabs 243 near the outside of the cell 20 cover the tabs 243 near the middle of the cell 20. The ends of each tab 243 in the negative electrode bundle near the middle of the cell 20 are relatively flush. The maximum number of stacked tabs 243 in the tab bundle 24 can be equal to the number of winding layers of the electrode sheet 22.
[0048] In one embodiment, in the first direction Y, the tab bundle 24 includes a first tab bundle 241 disposed in the middle of the cell 20 facing one side of the cell 20, and a second tab bundle 242 disposed in the middle of the cell 20 facing the other side of the cell 20; the cell 20 and the top cover 12 are disposed opposite each other in the third direction Z; in the second direction X, the first tab bundle 241 and the second tab bundle 242 are distributed at intervals.
[0049] The tab bundle 24 includes a first tab bundle 241 and a second tab bundle 242, which are distributed circumferentially around the cell 20. Each tab 243 in the first tab bundle 241 is connected to an electrode body 224 of a different ring, and each tab 243 in the second tab bundle 242 is connected to an electrode body 224 of a different ring. Furthermore, the electrode body 224 of the same ring is connected to tabs 243 of both the first tab bundle 241 and the second tab bundle 242. By using the above method, this embodiment sets up a first tab bundle 241 and a second tab bundle 242, increasing the number of groups of tab bundles 24 of the same polarity. The tabs 243 of the first tab bundle 241 and the second tab bundle 242 are welded to the same terminal post 13, thereby increasing the current path between the terminal post 13 and the cell 20, enhancing the current carrying capacity, and improving the rate performance of the single-cell battery 10.
[0050] The electrode 22 includes a positive electrode 221 and a negative electrode 222. The first electrode bundle 241 includes a first positive electrode bundle 241a and a first negative electrode bundle 241b. The second electrode bundle 242 includes a second positive electrode bundle 242a and a second negative electrode bundle 242b. The tabs 243 of the first positive electrode bundle 241a and the second positive electrode bundle 242a are connected to the electrode body 224 of the positive electrode 221. The tabs 243 of the first negative electrode bundle 241b and the second negative electrode bundle 242b are connected to the electrode body 224 of the negative electrode 222. In other words, for the positive electrode 221, the first electrode bundle 241 includes a first positive electrode bundle 241a, the second electrode bundle 242 includes a second positive electrode bundle 242a, and the tabs 243 of the first positive electrode bundle 241a and the second positive electrode bundle 242a are connected to the electrode body 224 of the positive electrode 221; for the negative electrode 222, the first electrode bundle 241 includes a first negative electrode bundle 241b, the second electrode bundle 242 includes a second negative electrode bundle 242b, and the tabs 243 of the first negative electrode bundle 241b and the second negative electrode bundle 242b are connected to the electrode body 224 of the negative electrode 222.
[0051] In one embodiment, the single-cell battery 10 has a first direction Y, and a third direction Z, a second direction X, and the first direction Y intersect each other in pairs. The cell 20 also includes two bent portions 25 and two connecting portions 26. The two bent portions 25 are spaced apart along the second direction X, and the two connecting portions 26 are spaced apart along the first direction Y. In the circumferential direction of the cell 20, the bent portions 25 and the connecting portions 26 are alternately connected, that is, one bent portion 25, one connecting portion 26, another bent portion 25, and another connecting portion 26 are connected sequentially. In other words, the cell 20 of this embodiment is divided into the two bent portions 25 and the two connecting portions 26 along its winding direction. The connecting portions 26 extend along the second direction X. The tabs 243 of the first tab bundle 241 and the tabs 243 of the second tab bundle 242 are both connected to the connecting portions 26.
[0052] In the above manner, since the connecting portion 26 of this embodiment extends along the second direction X, the electrode body 224 at the location of the connecting portion 26 has sufficient space to set the electrode tabs 243 of the first electrode tab bundle 241 and the electrode tabs 243 of the second electrode tab bundle 242, and can ensure that the electrode tabs 243 of the first electrode tab bundle 241 and the electrode tabs 243 of the second electrode tab bundle 242 maintain a relatively flat shape, which facilitates the welding of the electrode tabs 243 of the first electrode tab bundle 241 and the electrode tabs 243 of the second electrode tab bundle 242 to the electrode post 13.
[0053] Furthermore, the tab 243 of the first tab bundle 241 is connected to one of the two connecting portions 26, and the tab 243 of the second tab bundle 242 is connected to the other of the two connecting portions 26. In other words, in this embodiment, the first tab bundle 241 and the second tab bundle 242 are respectively disposed in different connecting portions 26, the first tab bundle 241 and the second tab bundle 242 are distributed along the first direction Y, and the tabs 243 of the first tab bundle 241 and the second tab bundle 242 are both bent toward the middle of the cell 20.
[0054] For example, the first positive electrode bundle 241a and the second positive electrode bundle 242a are disposed at one end of the battery cell 20 in the second direction X. The first positive electrode bundle 241a and the second positive electrode bundle 242a are respectively disposed at different connecting portions 26. The first positive electrode bundle 241a and the second positive electrode bundle 242a are distributed along the first direction Y, and the tabs 243 of the first positive electrode bundle 241a and the tabs 243 of the second positive electrode bundle 242a are both bent toward the middle of the battery cell 20. The end of the first positive electrode bundle 241a near the middle of the battery cell 20 and the end of the second positive electrode bundle 242a near the middle of the battery cell 20 form a welding area S1, and the welding area S1 is welded to the positive electrode post 13.
[0055] The first negative electrode bundle 241b and the second negative electrode bundle 242b are disposed at the other end of the cell 20 in the second direction X. The first positive electrode bundle 241a and the second positive electrode bundle 242a are stacked opposite to the first negative electrode bundle 241b and the second negative electrode bundle 242b and do not affect each other. The first negative electrode bundle 241b and the second negative electrode bundle 242b are respectively disposed at different connecting portions 26. The first negative electrode bundle 241b and the second negative electrode bundle 242b are distributed along the first direction Y, and the tabs 243 of the first negative electrode bundle 241b and the tabs 243 of the second negative electrode bundle 242b are both bent toward the middle of the cell 20. The end of the first negative electrode bundle 241b near the middle of the cell 20 and the end of the second negative electrode bundle 242b near the middle of the cell 20 form a welding area S2, which is welded to the negative electrode post 13.
[0056] In one embodiment, the battery cell 20 is a wound battery cell 20, with one end of the electrode body 224 being a winding end 223, and the electrode body 224 is wound around the winding end 223; along the first direction Y, the electrode body 224 includes layers 1, 2, 3...N sequentially from the inside out. When the electrode 22 is in a flattened state, the tabs 243 of the first tab bundle 241 and the tabs 243 of the second tab bundle 242 are alternately distributed in a direction away from the winding end 223; and when the electrode 22 is in a flattened state, the distance between the i-th tab 243 of the first tab bundle 241 and the i-th tab 243 of the second tab bundle 242 is L in the direction from the winding end 223 to the winding end 225. imm, where i is 1, 2, 3…N; satisfying: L i =L1+(i-1)πD. L1 satisfies: 20≤L1≤30, for example, L1 can be any value among 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30. In this way, by reasonably setting the spacing between the tabs 243 of the first tab bundle 241 and the tabs 243 of the second tab bundle 242 on the same loop of the electrode sheet 22, the tabs 243 on the electrode sheet 22 can be stacked to form the first tab bundle 241 and the second tab bundle 242 after the electrode sheet 22 is wound.
[0057] In one embodiment, when the electrode 22 is in a flattened state, the distance between the nth electrode 243 of the second electrode bundle 242 and the (n+1)th electrode 243 of the first electrode bundle 241 in the direction away from the winding end 223 is M. n mm, where n is 1, 2, 3…N-1; satisfying: M n =M1+(n-1)πD. That is, one end of the electrode body 224 is the winding end 223, and the electrode body 224 is wound around the winding end 223. When the electrode 22 is in a flattened state, the tabs 243 of the first tab bundle 241 and the tabs 243 of the second tab bundle 242 are alternately distributed in a direction away from the winding end 223. The total number of turns of the electrode body 224 is N. The distance between the tabs 243 of the second tab bundle 242 on the nth turn of the electrode body 224 and the tabs 243 of the first tab bundle 241 on the (n+1)th turn of the electrode body 224 is M. n mm, where n is 1, 2, 3…N-1. Satisfying: M n =M1+(n-1)πD. M1 satisfies: 100≤M1≤200, for example, M1 can be any value among 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, and 200. In this way, by reasonably setting the distance between the tabs 243 of the first tab bundle 241 and the tabs 243 of the second tab bundle 242 on adjacent loop electrode sheets 22, the tabs 243 on the electrode sheet 22 can be stacked to form the first tab bundle 241 and the second tab bundle 242 after the electrode sheet 22 is wound.
[0058] The following section evaluates the performance of the technical solution provided in the embodiments of this application. Taking the battery cell 20 used in a certain model of product as an example, H is confirmed by measuring with a ruler or vernier caliper. i L i and M i Parameters such as D are measured and confirmed using a ruler, vernier caliper, or micrometer.
[0059] The acceptance criteria are defined as a yield of 99.0% or less, with the folded tab 243 end within ±0.2 mm in the second direction Y. Examples 1 to 30 and comparative examples 1 to 4 are provided. Taking D = 0.4 as an example, examples 1 to 30 satisfy H. i =H1+(i-1)D、L i =L1+(i-1)πD and M n =M1+(n-1)πD. See the table below for specific parameters and test results.
[0060] Table 1
[0061]
[0062]
[0063] The tab alignment in the table should be understood as the degree of alignment of the ends of each tab 243 in the bent tab bundle 24 near the middle of the cell 20. Therefore, Examples 1 to 30, by reasonably setting the flattened length of each tab 243 in the same tab bundle 24, make the ends of each tab 243 near the middle of the cell 20 relatively flush after bending, which is beneficial to improving the space utilization of the receiving cavity 14 and facilitating the arrangement of the cell 20 in the receiving cavity 14. Furthermore, by reasonably setting the spacing between the tabs 243 of the first tab bundle 241 and the tabs 243 of the second tab bundle 242 on the same ring of electrode sheets 22, the L... i =L1+(i-1)πD, so that the tabs 243 on the wound electrode 22 can be stacked to form the first tab bundle 241 and the second tab bundle 242. In addition, by reasonably setting the spacing between the tabs 243 of the first tab bundle 241 and the tabs 243 of the second tab bundle 242 on adjacent loops of electrode 22, M is satisfied. n =M1+(n-1)πD, so that after the electrode sheet 22 is wound, the electrode tabs 243 on it can be stacked to form the first electrode tab bundle 241 and the second electrode tab bundle 242.
[0064] In contrast, in Comparative Examples 1-4, the flattened length of each tab 243 in the same tab bundle 24 was not properly set. After bending, the ends of each tab 243 in the tab bundle 24 near the middle of the cell 20 were not flush, which directly led to a reduction in the space utilization of the receiving cavity 14 and was not conducive to the layout of the cell 20 in the receiving cavity 14. In Comparative Examples 2 and 4, the spacing between the tabs 243 of the first tab bundle 241 and the tabs 243 of the second tab bundle 242 on the same coil of electrode sheet 22 was not properly set, and the yield was further reduced compared to Comparative Example 1. In Comparative Examples 3 and 4, the spacing between the tabs 243 of the first tab bundle 241 and the tabs 243 of the second tab bundle 242 on adjacent coils of electrode sheet 22 was not properly set, and the yield was further reduced compared to Comparative Example 1.
[0065] In summary, this application provides a single-cell battery and a battery pack. In this single-cell battery, the electrode of the cell includes an electrode body and multiple tabs connecting to the electrode body. These tabs, after being wound, form a tab bundle located on the side of the electrode body facing the top cover. In the tab bundle, each tab is stacked along a first direction, and each tab is bent towards the center of the cell, allowing the end of each tab near the center of the cell to be directly welded to the terminal post. In other words, this application eliminates the need for an adapter plate; instead, the tabs are directly welded to the terminal post. This avoids the adapter plate occupying internal space in the single-cell battery, which is beneficial for increasing the energy density of the single-cell battery. Furthermore, it reduces welding processes, which is beneficial for improving the manufacturing efficiency of the single-cell battery.
[0066] Furthermore, compared to a design where the flattened length of each tab remains constant, in this embodiment, the flattened length of each tab increases gradually from the center of the cell toward both sides of the cell. That is, the flattened length of the tabs near the center of the cell is smaller, which can reduce the amount of foil material used and help reduce the manufacturing cost of a single cell.
[0067] The single battery, battery pack, and power device provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A single cell, characterized by, The single battery comprises: a shell; a top cover, which is arranged on the shell and forms a containing cavity with the shell; a pole post, which is fixed to the top cover and penetrates the top cover; and a cell, which is arranged in the containing cavity and comprises a tab and a separator. The single battery has a first direction, the tab comprises a tab body and a plurality of tab lugs connected to the tab body, the plurality of tab lugs are arranged in a stack along the first direction and form a tab lug bundle on a side of the tab body facing the top cover, and the tab lug bundle is welded to one end of the pole post facing the cell.
2. The single battery of claim 1, wherein: In the first direction, the flattened length of each of the tabs increases in a direction from the middle of the battery cell to the two sides of the battery cell, and each of the tabs is arranged to be bent towards the middle of the battery cell; in the first direction, each of the tabs is sequentially numbered as 1, 2, 3…N in a direction from the middle of the battery cell to one side of the battery cell, and the flattened length of the i-th tab is H i mm, where i is 1, 2, 3…N, and satisfies: H i =H1+(i-1)D; the tabs include positive tabs and negative tabs, and D represents the thickness of one layer of positive tabs, the thickness of one layer of negative tabs, and the thickness of two layers of separators. in the first direction, the tab lug bundle comprises a first tab lug bundle arranged on one side of a middle portion of the cell and a second tab lug bundle arranged on the other side of the middle portion of the cell; the single battery further has a second direction and a third direction, the first direction, the second direction and the third direction intersect with each other, the cell and the top cover are arranged opposite to each other along the third direction, and in the second direction, the first tab lug bundle and the second tab lug bundle are distributed at intervals.
3. The single battery of claim 2, wherein: the cell is a winding type cell, one end of the tab body is a winding end, and the tab body is arranged in a winding manner around the winding end; along the first direction, the tab body comprises layers 1, 2, 3, …, N in sequence from inside to outside; when the tab is in a flat state, the tab lugs of the first tab lug bundle and the tab lugs of the second tab lug bundle are alternately distributed in a direction away from the winding end.
4. The single battery of claim 3, wherein: and a distance between an i-th one of the first tab bundle and an i-th one of the second tab bundle in a direction from the winding start end to the winding end is L when the pole piece is in the flattened state i mm, where i is 1, 2, 3, …, N; Satisfies: L i = L1+ (i-1)πD.
5. The single battery of claim 4, wherein: In the flattened state of the pole piece, the distance between the n-th pole tab of the second pole tab bundle and the n+1-th pole tab of the first pole tab bundle in the direction away from the winding end is M n mm, where n is 1, 2, 3, …, N-1; Satisfies: M n = M1+ (n-1)πD. in the first direction, the flat length H1 mm of the first tab lug satisfies: 4≤H1≤8; and / or in a direction from the winding end to the winding end, the distance L1 mm between the first tab lug of the first tab lug bundle and the first tab lug of the second tab lug bundle satisfies: 20≤L1≤30; and / or in a direction away from the winding end, the distance M1 mm between the first tab lug of the second tab lug bundle and the second tab lug of the first tab lug bundle satisfies: 100≤M1≤200.
6. The single battery of any one of claims 3 to 5, wherein: the cell further comprises two bending portions and two connecting portions, the two bending portions are distributed at intervals along the second direction, the two connecting portions are distributed at intervals along the first direction, each of the bending portions and each of the connecting portions are alternately connected in a circumferential direction of the cell, and the connecting portions extend along the second direction; wherein the tab lugs of the first tab lug bundle and the tab lugs of the second tab lug bundle are connected to the connecting portions.
7. The single battery of claim 6, wherein: the tab lugs of the first tab lug bundle are connected to one of the two connecting portions, and the tab lugs of the second tab lug bundle are connected to the other of the two connecting portions. 8. The unit cell according to any one of claims 2 to 5, characterized in that, the tab includes a positive tab and a negative tab, the first tab bundle includes a first positive tab bundle and a first negative tab bundle, and the second tab bundle includes a second positive tab bundle and a second negative tab bundle; the tab of the first positive tab bundle and the tab of the second positive tab bundle are connected to the tab body of the positive tab; and the tab of the first negative tab bundle and the tab of the second negative tab bundle are connected to the tab body of the negative tab.
9. A battery pack, characterized by, The battery pack according to claim 9, wherein the battery pack is a power supply for the electric device.
10. An electrical device, characterized by The battery pack according to claim 9, wherein the battery pack is a power supply for the electric device.