Cell core, battery cell, battery, and electric device

Abstract

A cell core, a battery cell, a battery, and an electric device. The cell core comprises a cell core body and a plurality of first tabs; the cell core body has a first end face and a second end face that are opposite to each other, and the cell core body is provided with a through hole passing through the first end face and the second end face. Each first tab is attached to the first end face, and has a connecting end and a welding end which serve as two longitudinal ends of the first tab, the connecting end is connected to the first end face, and the welding end blocks the through hole. The distance from the position of the connecting end of any first tab to the center of the through hole is the current radius r, and the length dimension L of any first tab satisfies that: L=r+a, wherein 5 mm≤a≤7 mm. In this way, the space of the through hole is used to weld the welding end of each first tab to a pole, so that there is no need to weld each first tab to a current collecting disc and then weld the pole to the current collecting disc, reducing one welding process.

Description

Battery cell, battery monomer, battery and electrical equipment Technical Field

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

[0002] Cylindrical batteries have the advantages of simple manufacturing, high consistency and low cost, and are widely used in electrical equipment such as power tools and power vehicles.

[0003] Traditionally, the positive and negative tabs in a battery cell are located at either end of the cell. The positive collector plate is welded to the positive tab, while the negative collector plate is welded to the negative tab. The positive collector plate is welded to the terminal post, while the negative collector plate is welded to the casing, making the terminal post and casing the positive and negative terminals of the battery cell, respectively. Consequently, the battery cell assembly process requires a high number of welding cycles. This poor controllability of welding quality significantly reduces the battery cell yield. Furthermore, multiple welds increase the total weld area, increasing the internal resistance of the battery cell. This significantly increases the temperature rise of the battery cell during overcurrent conditions, reducing the long-term stability of the battery cell.

[0004] Summary of the Invention

[0005] Based on this, it is necessary to provide a battery cell, battery cell, battery and electrical equipment that improve the above defects, in view of the fact that the number of welding operations required during the assembly of battery cells in the prior art is large, which on the one hand greatly reduces the yield rate of the battery cells; on the other hand, multiple welding leads to an increase in the total weld area, thereby increasing the internal resistance of the battery cells, and further greatly increases the temperature rise of the battery cells during overcurrent, reducing the long-term stability of the battery cells.

[0006] A battery cell comprises a battery cell body and a plurality of first tabs, wherein the battery cell body has a first end face and a second end face opposite to each other, and the battery cell body further has a through hole penetrating the first end face and the second end face; each first tab is attached to the first end face and has a connecting end and a welding end as two longitudinal ends of the first tab, the connecting end being connected to the first end face, and the welding end shielding the through hole;

[0007] The distance from the connection end of any first tab to the center of the through hole is the current radius r, and the length dimension L of any first tab satisfies: L=r+a, 5mm≤a≤7mm.

[0008] In one embodiment, a=6 mm.

[0009] In one embodiment, the battery cell body is formed by winding a first electrode sheet strip, a first diaphragm strip, a second electrode sheet strip and a second diaphragm strip stacked in sequence; the connecting end of each first electrode tab is connected to a side edge in the width direction of the first electrode sheet strip, and is arranged at intervals along the length direction of the first electrode sheet strip.

[0010] In one embodiment, the length of each of the first electrode tabs gradually increases from one end of the first electrode strip located inside the battery cell body to one end located outside the battery cell body.

[0011] In one embodiment, from the inner side to the outer side of the battery cell body, every N turns of the first electrode material strip constitute a group of electrode turns;

[0012] The lengths of the first pole tabs on the first pole piece strip of each group of the pole piece rings are equal, and the difference △L in the lengths of the first pole tabs on each two adjacent groups of the pole piece rings satisfies: △L=N×t, where t is the sum of the thicknesses of one layer of the first pole piece strip, one layer of the first diaphragm strip, one layer of the second pole piece strip and one layer of the second diaphragm strip.

[0013] In one embodiment, when t≤0.5 mm, 5<N≤10; or

[0014] When 0.5mm<t≤1mm, 3<N≤5; or

[0015] When 1mm<t, N≤3.

[0016] In one embodiment, the battery cell further includes a plurality of second pole tabs, one end of each of the second pole tabs is connected to the second end surface and is bent toward the through hole and attached to the second end surface, and the other end of each of the second pole tabs does not cover the through hole.

[0017] In one embodiment, the battery cell body is formed by winding a first electrode sheet, a first diaphragm sheet, a second electrode sheet and a second diaphragm sheet in sequence; one end of each second electrode tab is connected to the second electrode sheet and is arranged at intervals along the length direction of the second electrode sheet.

[0018] In one embodiment, the lengths of the second electrode tabs are equal.

[0019] A battery cell comprises a shell, a pole and a battery cell as described in any of the above embodiments; the pole is insulated and arranged at one end of the shell, the battery cell is accommodated in the shell, and the end of the battery cell having the first end face facing the pole, and the welding end of each first pole ear is welded to the pole.

[0020] In one embodiment, the battery cell further includes a cover plate, and the second end face of the battery cell body has a plurality of second tabs. The cover plate is connected to an end of the shell away from the pole and is welded to each of the second tabs on the second end face.

[0021] In one embodiment, a liquid injection hole is formed on the cover plate and is opposite to the through hole on the battery cell body, and the liquid injection hole is sealed by a sealing nail.

[0022] A battery comprises the battery cell described in any one of the above embodiments.

[0023] An electrical device comprises the battery described in any one of the above embodiments.

[0024] In the aforementioned battery cells, battery cells, batteries, and electrical equipment, the length of the first tab located outside the battery cell body is greater than the length of the first tab located inside the battery cell body. Specifically, the length L of each first tab is designed to satisfy L = r + a, 5 mm ≤ a ≤ 7 mm, thereby ensuring that the welding end of each first tab, which is bent toward the through-hole and attached to the first end surface, is located at the through-hole. The pole, insulated and mounted on the housing, contacts the welding end of the first tab at the through-hole, enabling torque welding of the welding end of each first tab to the pole using a welding pin passing through the through-hole. In other words, the space in the through-hole is utilized to weld the welding end of each first tab to the pole, eliminating the need to weld each first tab to the current collector plate before welding the pole to the current collector plate. This reduces a welding step, facilitating improved battery cell yield, while also eliminating a weld mark and lowering the internal resistance of the battery cell. This reduces the temperature rise of the battery cell during overcurrent conditions and enhances the long-term stability of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a cross-sectional view of a battery cell in one embodiment of the present application;

[0026] FIG2 is a schematic structural diagram of a battery cell at a first end surface of the battery cell shown in FIG1 ;

[0027] FIG3 is a schematic diagram of the expansion of the first electrode sheet strip of the battery cell shown in FIG1 ;

[0028] FIG4 is a schematic diagram of an expanded first electrode strip of a battery cell of a battery cell in another embodiment of the present application;

[0029] FIG5 is a schematic structural diagram of the battery cell at the second end surface of the battery cell shown in FIG1 ;

[0030] FIG6 is a schematic diagram of the expansion of the second electrode strip of the battery cell shown in FIG5 . DETAILED DESCRIPTION

[0031] 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.

[0032] 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", etc., indicating the orientation or position relationship, are based on the orientation or position relationship 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 cannot be understood as a limitation on the present application.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] An embodiment of the present application provides an electric device that uses a battery as its power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, and the like.

[0038] Specifically, in this embodiment, the battery includes a housing and a battery cell. The battery cell contains one or more battery cells. The battery cell is housed within the housing. The housing provides space for the battery cell and can have various structures and shapes, such as a cylinder or a rectangular parallelepiped.

[0039] 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.

[0040] Referring to Figures 1 to 3 , one embodiment of the present application provides a battery cell comprising a housing 20 , a battery cell 10 , and a terminal 30 . The battery cell 10 includes a battery body 11 and a plurality of first tabs 13 . The battery body 11 has a first end face 111 and a second end face 112 , which face each other. The battery body 11 also has a through-hole 15 extending through the first and second end faces 111 and 112 . Each first tab 13 is attached to the first end face 111 and has a connecting end 131 and a welding end 132 , which serve as the longitudinal ends of the first tab 13 . The connecting end 131 is connected to the first end face 111 , and the welding end 132 shields the through-hole 15 . The distance from the connecting end 131 of any first tab 13 to the center of the through-hole 15 is the current radius r . The length dimension L of any first tab 13 satisfies the following conditions: L = r + a, 5 mm ≤ a ≤ 7 mm. Preferably, a = 6 mm. The terminal 30 is insulated and disposed at one end of the housing 20 . The battery cell 10 is housed in the housing 20 , and one end of the battery cell 10 having the first end surface 111 faces the electrode 30 . The electrode 30 is welded to the welding end 132 of each first electrode tab 13 .

[0041] In the battery cell described above, the length of the first tab 13 located outside the cell body 11 is greater than the length of the first tab 13 located inside the cell body 11. Specifically, the length L of each first tab 13 is designed to satisfy L = r + a, 5 mm ≤ a ≤ 7 mm. This ensures that the weld end 132 of each first tab 13, which is bent toward the through-hole 15 and attached to the first end surface 111, is located at the through-hole 15. The pole 30, insulated and mounted on the housing 20, contacts the weld end 132 of the first tab 13 at the through-hole 15, enabling torque welding of the weld end 132 of each first tab 13 to the pole 30 using a welding pin passing through the through-hole 15. That is to say, the space of the through hole 15 is utilized to weld the welding end 132 of each first pole ear 13 to the pole post 30. There is no need to weld each first pole ear 13 to the current collecting plate and then weld the pole post 30 to the current collecting plate. This reduces one welding process, which is beneficial to improving the yield of the battery cell. At the same time, it reduces one weld mark, reduces the internal resistance of the battery cell, and is beneficial to reducing the temperature rise of the battery cell during overcurrent, thereby increasing the stability of the battery cell during long-term use.

[0042] In the embodiment of the present application, the battery cell body 11 is formed by winding a first electrode sheet strip 17 (see Figure 3 or Figure 4), a first diaphragm strip, a second electrode sheet strip 19, and a second diaphragm strip stacked in sequence. The connection end 131 of each first pole tab 13 is connected to a side edge in the width direction of the first pole sheet strip 17, and is arranged at intervals along the length direction of the first pole sheet strip 17, so that each first pole tab 13 is located on the first end face 111 of the battery cell body 11. After the flattening or kneading process, each first pole tab 13 is bent toward the through hole 15 and attached to the first end face 111, so that the welding end 132 of each first pole tab 13 is located at the through hole 15, so as to facilitate welding the welding end 132 of each first pole tab 13 to the pole column 30.

[0043] In some embodiments, as shown in Figure 3, the length of each first pole tab 13 gradually increases from the end of the first electrode sheet 17 located on the inner side of the battery cell body 11 to the end located on the outer side of the battery cell body 11 to ensure that the welding end 132 of each first pole tab 13 can be located at the through hole 15 after the flattening or kneading process, which is convenient for welding with the pole 30.

[0044] In other embodiments, as shown in FIG4 , from the inside to the outside of the cell body 11, every N turns of the first electrode strip 17 constitute a group of electrode strips 171. The lengths of the first pole tabs 13 on the first electrode strip 17 of each group of electrode strips 171 are equal, and the difference ΔL in the lengths of the first pole tabs 13 between two adjacent groups of electrode strips 171 satisfies: ΔL=N×t, where t is the sum of the thicknesses of one layer of the first electrode strip 17, one layer of the first diaphragm strip, one layer of the second electrode strip 19, and one layer of the second diaphragm strip. In this way, by dividing each circle of the first electrode sheet material strip 17 of the battery cell body 11 into a group of electrode sheet circles 171 every N circles, and by designing the length dimension of the first electrode tab 13 on the first electrode sheet material strip 17 of each group of electrode sheet circles 171 (that is, satisfying △L=N×t), on the one hand, it is ensured that the welding end 132 of each first electrode tab 13 can be located at the through hole 15 after the flattening or kneading process, and on the other hand, it is ensured that the length of the welding end 132 located at the through hole 15 is moderate, so as to avoid the welding end 132 located at the through hole 15 from being too long and piercing into the interior of the battery cell body 11 (that is, between the layers of material strips).

[0045] Optionally, t≤0.5 mm, then 5<N≤10, thereby ensuring that the welding end 132 located at the through hole 15 will not be too long and will not penetrate into the battery cell body 11 .

[0046] Optionally, 0.5 mm < t ≤ 1 mm, then 3 < N ≤ 5, thereby ensuring that the welding end 132 located at the through hole 15 will not be too long and will not penetrate into the battery cell body 11 .

[0047] Optionally, 1 mm<t, then N≤3, thereby ensuring that the welding end 132 located at the through hole 15 will not be too long and will not penetrate into the battery cell body 11 .

[0048] Specifically in the embodiment, the first electrode tab 13 may be in the shape of a trapezoid. Of course, in other embodiments, the first electrode tab 13 may also be in the shape of a triangle, a rectangle, etc., which is not limited here.

[0049] In the embodiment of the present application, the battery cell 10 further includes a plurality of second pole tabs 14, one end of each second pole tab 14 being connected to the second end face 112 and being bent toward the through hole 15 and attached to the second end face 112, and the other end of each second pole tab 14 does not cover the through hole 15. In this way, since each second pole tab 14 does not cover the through hole 15, it is ensured that the welding needle can pass through the through hole 15 and reach the welding end 132 of each first pole tab 13, so as to achieve welding of the welding end 132 of each first pole tab 13 to the pole 30. Furthermore, the battery cell further includes a cover plate 40 (see FIG. 1 ), which is connected to the end of the housing 20 away from the pole 30, so that the second end face 112 of the battery cell body 11 faces the cover plate 40. The cover plate 40 is welded to each second pole tab 14 on the second end face 112.

[0050] It should be noted that the second pole tabs 14 on the second end face 112 are directly welded to the cover plate 40, thereby realizing electrical connection with the cover plate 40 and the shell 20. There is no need to weld the second pole tabs 14 to the collecting plate and then weld the collecting plate to the bottom cover, which reduces one welding process, is beneficial to improving the yield of the battery cell, and at the same time reduces one weld mark, reduces the internal resistance of the battery cell, is beneficial to reducing the temperature rise of the battery cell during overcurrent, and increases the stability of the battery cell during long-term use.

[0051] Specifically in the embodiment, each second pole tab 14 is connected to a side edge of the second pole sheet strip 19 in the width direction and is spaced apart along the length direction of the second pole sheet strip 19. Thus, when the first pole sheet strip 17, the first diaphragm strip, the second pole sheet strip 19, and the second diaphragm strip, which are stacked in sequence, are wound into a battery cell 10, each first pole tab 13 is located on the first end face 111 of the battery cell body 11, and each second pole tab 14 is located on the second end face 112 of the battery cell body 11. After a flattening or kneading process, each first pole tab 13 is bent toward the through hole 15 and attached to the first end face 111, and each second pole tab 14 is bent toward the through hole 15 and attached to the second end face 112.

[0052] Furthermore, the cover plate 40 is provided with an injection hole (not shown) opposite to the through hole 15 of the cell body 11, through which electrolyte can be injected into the housing 20. The injection hole can be sealed with a sealing pin. Thus, when welding the welding end 132 of each first pole tab 13 to the pole 30, the welding needle is first passed through the injection hole on the cover plate 40 and the through hole 15 of the cell body 11 in sequence until it reaches the welding end 132 of each first pole tab 13; then, the welding needle is used to torque weld the welding end 132 of each first pole tab 13 to the pole 30.

[0053] It should be noted that in one embodiment, if the first electrode strip 17 is a positive electrode, then the first electrode tab 13 is a positive electrode tab, and the electrode column 30 serves as the positive electrode of the battery cell. If the second electrode strip 19 is a negative electrode, then the second electrode tab 14 is a negative electrode tab, and the cover plate 40 or the housing 20 serves as the negative electrode of the battery cell.

[0054] Of course, in another embodiment, the first electrode strip 17 can also be a negative electrode, in which case the first electrode tab 13 is a negative electrode tab, and the electrode post 30 serves as the negative electrode of the battery cell. The second electrode strip 19 is a positive electrode, in which case the second electrode tab 14 is a positive electrode tab, and the cover 40 or the housing 20 serves as the positive electrode of the battery cell.

[0055] It should be noted that the lengths of the second tabs 14 can be designed to be equal, which helps to reduce the difficulty of processing the second tabs 14 and improve the processing efficiency of the second tabs 14. Optionally, the second tabs 14 can be trapezoidal, triangular, or rectangular, etc., which is not limited 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: The battery cell body (11) comprises a battery cell body (11) and a plurality of first pole tabs (13); the battery cell body (11) comprises a first end face (111) and a second end face (112) which are opposite to each other; the battery cell body (11) further comprises a through hole (15) which penetrates the first end face (111) and the second end face (112); each of the first pole tabs (13) is attached to the first end face (111) and comprises a connecting end (131) and a welding end (132) which are two longitudinal ends of the first pole tab (13); the connecting end (131) is connected to the first end face (111), and the welding end (132) covers the through hole (15); The distance from the position of the connection end (131) of any of the first pole tabs (13) to the center of the through hole (15) is the current radius r, and the length dimension L of any of the first pole tabs (13) satisfies: L=r+a, 5mm≤a≤7mm.

2. The battery cell according to claim 1, characterized in that: a=6mm.

3. The battery cell according to claim 1, characterized in that: The battery cell body (11) is formed by winding a first pole piece strip (17), a first diaphragm strip, a second pole piece strip (19) and a second diaphragm strip which are stacked in sequence; the connecting end (131) of each of the first pole tabs (13) is connected to the first pole piece strip (17) and arranged at intervals along the length direction of the first pole piece strip (17).

4. The battery cell according to claim 3, characterized in that: From one end of the first pole piece strip (17) located inside the battery cell body (11) to one end located outside the battery cell body (11), the length of each of the first pole tabs (13) gradually increases.

5. The battery cell according to claim 3, characterized in that: From the inside to the outside of the battery cell body (11), every N turns of the first pole piece strip (17) constitute a group of pole piece turns (171); The lengths of the first pole lugs (13) on the first pole piece strip (17) of each group of the pole piece rings (171) are equal, and the difference ΔL between the lengths of the first pole lugs (13) on each two adjacent groups of the pole piece rings (171) satisfies: ΔL=N×t, where t is a layer of the first pole piece strip (17), The sum of the thicknesses of a layer of the first diaphragm material strip, a layer of the second pole piece material strip (19) and a layer of the second diaphragm material strip.

6. The battery cell according to claim 5, characterized in that: When t≤0.5mm, 5<N≤10.

7. The battery cell according to claim 5, characterized in that: When 0.5mm<t≤1mm, 3<N≤5.

8. The battery cell according to claim 5, characterized in that: When 1mm<t, N≤3.

9. The battery cell according to any one of claims 1 to 8, characterized in that: The battery cell (10) further comprises a plurality of second pole tabs (14), one end of each of the second pole tabs (14) being connected to the second end surface (112) and being bent toward the through hole (15) and attached to the second end surface (112), and the other end of each of the second pole tabs (14) not covering the through hole (15).

10. The battery cell according to claim 9, characterized in that: The cell body (11) is formed by winding a first pole piece strip (17), a first diaphragm strip, a second pole piece strip (19) and a second diaphragm strip stacked in sequence; one end of each of the second pole tabs (14) is connected to the second pole piece strip (19) and arranged at intervals along the length direction of the second pole piece strip (19).

11. The battery cell according to claim 9, characterized in that: The lengths of the second pole tabs (14) are equal.

12. A battery cell, characterized in that: It comprises a shell (20), a pole (30) and a battery cell (10) as claimed in any one of claims 1 to 11; the pole (30) is insulated and arranged on the shell (20), the battery cell (10) is accommodated in the shell (20), and the battery cell (10) has one end of the first end face (111) facing the pole (30), and the welding end (132) of each first pole ear (13) is welded to the pole (30).

13. The battery cell according to claim 12, characterized in that: The battery cell also includes a cover plate (40), and the second end surface (112) of the battery cell body (11) has a plurality of second pole tabs (14). The cover plate (40) is connected to an end of the shell (20) away from the pole (30) and is welded to each of the second pole tabs (14) on the second end surface (112).

14. The battery cell according to claim 13, characterized in that: The cover plate (40) is provided with a liquid injection hole opposite to the through hole (15) on the battery cell body (11), and the liquid injection hole is sealed by a sealing nail.

15. A battery, characterized in that: Comprising the battery cell according to any one of claims 12 to 14.

16. An electrical equipment, characterized in that: Comprising the battery of claim 15.

Images