Batteries and battery packs

Abstract

In a cell (10) having at least one electrode body (20), each electrode body (20) has a plurality of tabs (201), and the plurality of tabs (201) are gathered together and then welded to the cover plate (30) of the battery (100) to form a weld. Before the electrode body (20) is gathered or when the electrode body (20) is unfolded and parallel to the cover plate (30), the distance from the electrode body (20) to the weld is determined based on the thickness of the electrode body (20), the bend angle of the tab (201), and the width of the tab (201) protective piece at the weld.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority from Chinese Patent Application No. "202010900497.8" filed by BD Company Limited on August 31, 2020, for an invention entitled "Battery and Battery Pack." [Background technology]

[0002] This application relates to the field of batteries, and more particularly to batteries and battery packs having such batteries.

[0003] In the related art, multiple tabs of the electrode body are welded together after being gathered, and the position of the welding point affects the length of the tab free area. If the spacing distance from the electrode body to the midpoint of the welding point is designed to be too small when the electrode body is parallel to the cover plate before being gathered or after being unfolded, the tab is likely to be pulled after being bent, resulting in tab breakage. The broken tab will result in some electrode pieces being unable to electrically draw out, causing a loss of cell capacity.

[0004] If the gap between the electrode body and the midpoint of the welding point is designed to be too large, the movable length of the tab will be increased, requiring a larger bending space to accommodate the tab. However, designing a larger bending space will result in a loss of cell capacity; if the bending space is not increased, the tab will be pressed, easily causing contact between the positive and negative electrodes, posing a safety risk to the battery. Summary of the Invention

[0005] The present application aims to solve at least one of the technical problems in the prior art, and therefore, one object of the present application is to provide a battery that can prevent the tab from being pulled after bending, thereby avoiding loss of cell capacity, and also can prevent the tab from being pressed, thereby improving safety in use.

[0006] The present application further provides a battery pack including the above battery.

[0007] The battery according to the present application includes a cell having at least one electrode body, each of which has a plurality of tabs, and which is welded to a cover plate of the battery after being gathered to form a weld point, and when the electrode body is parallel to the cover plate before being gathered or after being deployed, the distance from the electrode body to the weld point is determined based on the thickness of the electrode body, the tab bending angle of the tab, and the width of the tab protection piece at the weld point.

[0008] According to the battery of the present application, the gap distance between the electrode body and the welding point can be made more appropriate, preventing the tab from being pulled after bending and preventing breakage, thereby avoiding loss of cell capacity. In addition, by making the movable length of the tab appropriate and making the bending space appropriate, loss of cell capacity can be avoided and the tab can be prevented from being pressed, thereby improving the safety of battery use.

[0009] In some examples of the present application, the distance from the electrode body to the welding point is L1, the thickness of the electrode body is D, the width of the tab protection piece is d1, and the tab bending angle of the tab is A, which satisfies the relationship L1 = D / 2 × tan A + d1 / 2.

[0010] In some examples of the present application, 45°≦A≦135° is satisfied.

[0011] In some examples of the present application, when the electrode body is parallel to the cover plate before being converged or after being deployed, a tab free area is formed between the electrode body and the welding point, and the length of the tab free area is determined based on the tab pull-out method of the electrode body.

[0012] In some examples of the present application, the electrode body is configured as a wound electrode body. When the tab is drawn out by the tab semi-drawing method in the electrode body, the thickness of the electrode body is D, the length of the tab exposed from the electrode body in the extending direction of the tab is L2, the length of the tab free region is L3, and the relational expression 0.25D < L3 < L2 is satisfied.

[0013] In some examples of the present application, when the tab is drawn out by the tab full-drawing method in the electrode body, the thickness of the electrode body is D, the length of the tab exposed from the electrode body in the extending direction of the tab is L2, the length of the tab free region is L3, and the relational expression 0.5D < L3 < L2 is satisfied.

[0014] In some examples of the present application, a plurality of the tabs are converged to form a tab convergence drawing position. In the thickness direction of the electrode body, the tab convergence drawing position includes a zero drawing position, an intermediate drawing position, and a non-uniform drawing position, and the tab convergence drawing position is located at the zero drawing position or the non-uniform drawing position.

[0015] In some examples of the present application, a plurality of the tabs are converged to form a tab convergence drawing position. In the thickness direction of the electrode body, the tab convergence drawing position includes a zero drawing position, an intermediate drawing position, and a non-uniform drawing position, and the tab convergence drawing position is located at the intermediate drawing position. <0000​​​​​​​​​​​​​The battery pack according to the present application includes the above battery.

[0020] The battery pack according to the present application is provided with the battery of the above embodiment, and since the battery of the above embodiment is provided with the battery of the present application, the battery pack is safe.

[0021] Additional aspects and advantages of the present application will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the present application. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a cross-sectional view of a battery according to an embodiment of the present application. [Figure 2] 1 is a schematic diagram of an electrode assembly of a battery according to an embodiment of the present application when it is parallel to the cover plate after being deployed. FIG. [Figure 3] FIG. 2 is a schematic diagram of an electrode assembly of a battery according to an embodiment of the present invention when the electrode assembly is in a zero-pullout position. [Figure 4] 1 is a schematic diagram illustrating a battery according to an embodiment of the present invention in which an electrode body is located at an unevenly distributed drawn-out position. [Figure 5] 1 is a schematic diagram of an electrode assembly of a battery according to an embodiment of the present invention when the electrode assembly is located at an intermediate pull-out position. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, the embodiments of the present application will be described in detail, and examples of the embodiments are shown in the drawings, and the same or similar reference numerals throughout indicate the same or similar parts or parts having the same or similar functions. The embodiments described below with reference to the drawings are merely illustrative and are intended to interpret the present application, but should not be understood to limit the present application.

[0024] Hereinafter, a battery 100 according to an embodiment of the present invention will be described with reference to FIGS.

[0025] As shown in FIGS. 1 to 5 , a battery 100 according to an embodiment of the present application includes a cell 10 having at least one electrode assembly 20, each electrode assembly 20 having a plurality of tabs 201, which are welded to a cover plate 30 of the battery 100 after being gathered to form a weld 40, and when the electrode assembly 20 is parallel to the cover plate 30 before being gathered or after being unfolded, i.e., when the electrode assembly 20 is parallel to the cover plate 30 before being gathered or when the electrode assembly 20 is parallel to the cover plate 30 after being unfolded, the distance from the electrode assembly 20 to the weld 40 is determined based on the thickness of the electrode assembly 20, the tab bending angle of the tab 201, and the width of the tab protection piece at the weld 40 in the extension direction of the tab 201.

[0026] A tab protection piece is arranged at the welding point 40, and each electrode body 20 has a plurality of separators 202. The distance from the end of the separator 202 facing the welding point 40 to the welding point 40 is determined based on the thickness of the electrode body 20, the tab bending angle of the tab 201, and the width of the tab protection piece in the extension direction of the tab 201. Note that the thickness direction of the electrode body 20 is the thickness direction of the electrode body 20 in Figures 3 to 5, and the extension direction of the tab 201 is the left-right direction in Figures 3 to 5.

[0027] By determining the gap distance between the electrode assembly 20 and the welding point 40 based on the thickness of the electrode assembly 20, the tab bending angle of the tab 201, and the width of the tab protection piece at the welding point 40 in the extension direction of the tab 201, the gap distance between the electrode assembly 20 and the welding point 40 can be made more appropriate, preventing the tab 201 from being pulled after bending and preventing the tab 201 from breaking, thereby preventing some electrode pieces from being unable to provide electrical leads and further reducing capacity loss in the cell 10. In addition, by optimizing the movable length of the tab 201 and optimizing the bending space that accommodates the tab 201, capacity loss in the cell 10 can be avoided and the tab 201 can be prevented from being pressed, thereby preventing contact between the positive and negative electrodes of the cell 10 and preventing short-circuiting of the cell 10, and further improving the safety of use of the battery 100.

[0028] In some embodiments of the present application, the distance between the electrode assembly 20 and the welding point 40 is L1, the thickness of the electrode assembly 20 is D, the width of the tab protection piece is d1, and the tab bending angle of the tab 201 is A, which satisfy the relationship L1=D / 2×tanA+d1 / 2, and the bending angle A of the tab 201 satisfies the relationship 45°≦A≦135°. The distance between the end of the separator 202 of the electrode assembly 20 facing the welding point 40 and the welding point 40 is L1. By setting the distance L1 in this manner, it is possible to further prevent the tab 201 from being pulled after bending and to further prevent the tab 201 from breaking, which further prevents some of the electrode pieces from being unable to perform electrical extraction and further prevents capacity loss of the cell 10. Furthermore, by optimizing the movable length of the tab 201 and the bending space for accommodating the tab 201, it is possible to further avoid capacity loss of the cell 10 and further prevent the tab 201 from being pressed, thereby further preventing contact between the positive and negative electrodes of the cell 10 and better preventing short circuits of the cell 10, thereby further improving the safety of use of the battery 100.

[0029] In some embodiments of the present application, the width of the tab protection piece can be set to 8 to 12 mm. By setting the width of the tab protection piece in this manner, the tab 201 can be properly protected, and the tab 201 can be more effectively prevented from being pulled after being bent and from breaking, thereby further preventing some electrode pieces from being unable to provide electrical leads and further reducing capacity loss in the cell 10. In addition, by properly adjusting the movable length of the tab 201 and the bending space for accommodating the tab 201, capacity loss in the cell 10 can be further reduced and the tab 201 can be more effectively prevented from being pressed, thereby further preventing contact between the positive and negative electrodes of the cell 10 and better preventing short-circuiting of the cell 10, thereby further improving the safety of use of the battery 100.

[0030] In some embodiments of the present application, when the electrode assembly 20 is parallel to the cover plate 30 before being gathered or after being unfolded, i.e., when the electrode assembly 20 is parallel to the cover plate 30 before being gathered or when the electrode assembly 20 is parallel to the cover plate 30 after being unfolded, a tab free region is formed between the electrode assembly 20 and the welding point 40 in the extension direction of the tab 201, as shown in FIG. 2 . In one embodiment of the present application, after the plurality of tabs 201 are gathered, a tab free region is formed between the welding point 40 and the end of the separator 202 facing the welding point 40, and the length of the tab free region is determined based on the pull-out manner of the tab 201 of the electrode assembly 20. This setting makes the length of the tab free region more appropriate, further preventing the tab 201 from being pulled after being bent and further preventing some electrode pieces from being unable to be electrically pulled out, thereby further preventing capacity loss of the cell 10. Furthermore, by optimizing the movable length of the tab 201 and the bending space for accommodating the tab 201, it is possible to further avoid capacity loss of the cell 10 and prevent the tab 201 from being pressed, thereby further preventing contact between the positive and negative electrodes of the cell 10 and better preventing short circuits of the cell 10, thereby further improving the safety of use of the battery 100. At the same time, it is possible to ensure that the bending angle of the tab 201 is more appropriate.

[0031] In one embodiment of the present application, as shown in FIGS. 3 and 4, the electrode body 20 is configured as a wound electrode body 20. When the tab 201 is drawn out by the tab semi-drawing method, the tab semi-drawing method refers to the tab semi-drawing method in which only one tab 201 is drawn out per one turn of the wound electrode body 20 after the electrode body 20 is wound. The tab semi-drawing method is only applicable to the wound electrode body 20. The thickness of the electrode body 20 is D, and the length of the tab 201 exposed from the electrode body 20 in the extending direction of the tab 201 is L2. That is, the length of the tab 201 exposed from the separator 202 of the tab 201 in the extending direction of the tab 201 is L2. The length of the tab free region is L3, and it satisfies the relational expression 0.25D < L3 < L2. By setting it in this way, after a plurality of tabs 201 are integrally welded, the length dimension of the tab free region can be made appropriate, the breakage of the tab 201 can be prevented, and the pressing of the tab 201 can be prevented, and the risk of the cell 10 being short-circuited can be further reduced.

[0032] In some embodiments of the present application, the plurality of tabs 201 are converged to form a tab converged pull-out position, which may include a zero pull-out position 50, an intermediate pull-out position 60, and an offset pull-out position 70 in the thickness direction of the electrode body 20. As shown in FIG. 3 , the tab converged pull-out position may be located at the zero pull-out position 50, and as shown in FIG. 4 , the tab converged pull-out position may be located at the offset pull-out position 70. The intermediate pull-out position 60 overlaps with the central axis 80 of the electrode assembly 20, and in the thickness direction of the electrode assembly 20, the zero pull-out position 50 is located on the axis where the outermost layer of the electrode assembly 20 is located. The eccentric pull-out position 70 is located between the zero pull-out position 50 and the intermediate pull-out position 60. The thicker the cell 10, the closer the convergent pull-out position of the tab 201 is to the intermediate pull-out position 60. The thinner the cell 10, the closer the convergent pull-out position of the tab 201 is to the zero pull-out position 50. By arranging the tab 201 in this manner, the tab bending angle of the tab 201 can be optimized, ensuring that the tab 201 does not press against the separator 202 and reducing the risk of damage to the separator 202. This reduces the risk of a short circuit occurring inside the cell 10 and further improves the safety of use of the battery 100.

[0033] In another embodiment of the present application, as shown in FIG. 5, when the tab 201 of the electrode body 20 is pulled out by the full-tab pulling-out method, the full-tab pulling-out method refers to the full-tab pulling-out method in which the tab 201 is pulled out from each electrode sheet of the electrode body 20 when the electrode body 20 is a laminated electrode body, or when the electrode body 20 is a wound electrode body, with the diameter of the electrode body 20 as the center of symmetry, two tabs 201 are symmetrically arranged on each wound electrode sheet of the electrode body 20, and such an arrangement method of the tab 201 is also the full-tab pulling-out method. The laminated electrode body needs to select the full-tab pulling-out, and the wound electrode body 20 may or may not select the full-tab pulling-out. The thickness of the electrode body 20 is D, and the length of the tab 201 exposed from the electrode body 20 in the extending direction of the tab 201 is L2, that is, the length of the tab 201 exposed from the separator 202 in the extending direction of the tab 201 is L2, and the length of the tab free region is L3, satisfying the relational expression 0.5D < L3 < L2. By setting it in this way, the length dimension of the tab free region can be made appropriate, preventing the tab 201 from breaking and preventing the tab 201 from being pressed, and further reducing the risk of the cell being short-circuited.

[0034] Furthermore, the plurality of tabs 201 are concentrated to form a tab concentration pulling-out position. In the thickness direction of the electrode body 20, the tab concentration pulling-out position includes a zero pulling-out position 50, an intermediate pulling-out position 60, and an uneven pulling-out position 70. As shown in FIG. 5, the tab concentration pulling-out position may be located at the intermediate pulling-out position 60. By arranging it in this way, the tab bending angle of the tab 201 can be made appropriate, ensuring that the tab 201 does not press the separator 202, reducing the risk of the separator २०२ being damaged, reducing the risk of a short circuit occurring inside the cell 10, and further improving the use safety of the battery 100.

[0035] In some embodiments of the present application, the weld points 40 may be disposed in the weld point regions of the tabs 201, which may include ultrasonic weld regions and laser weld regions, with the laser weld region being located within the ultrasonic weld region, i.e., overlapping the ultrasonic weld region. First, the tabs 201 are converged by being ultrasonically welded together in the ultrasonic weld region, and then the converged tabs 201 are welded to the cover plate 30 by laser welding in the laser weld region. This arrangement ensures that the tabs 201 are reliably welded to the cover plate 30 and prevents separation between the tabs 201 and the cover plate 30, thereby ensuring the operational reliability of the battery 100.

[0036] Furthermore, the width of the ultrasonic welding area in the extension direction of the tabs 201 may be set to 4 to 8 mm, and preferably set to 6 mm. By setting it in this manner, the width dimension of the ultrasonic welding area can be made appropriate, multiple tabs 201 can be reliably welded, and welding quality can be guaranteed. Note that the distance from the electrode body 20 to the welding point refers to the distance from the electrode body 20 to the center point of the laser welding point.

[0037] The battery pack according to the embodiment of the present application includes the battery 100 according to the above embodiment, and the battery 100 is disposed in the battery pack. The distance between the electrode body 20 and the welding point 40 is more appropriate, and the tab 201 is prevented from being pulled after being bent and from breaking, thereby preventing capacity loss of the cell 10. In addition, the movable length of the tab 201 can be made appropriate, and the bending space can be made appropriate, thereby preventing capacity loss of the cell 10 and preventing the tab 201 from being pressed, thereby improving the safety of the battery 100 when in use.

[0038] In the description herein, the use of a reference phrase such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "particular example," or "some examples" means that the specific features, structures, materials, or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the description herein, exemplary references to the phrase are not necessarily limited to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples, as appropriate.

[0039] Although the embodiments of the present application have been illustrated and described, as will be understood by those skilled in the art, various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is limited by the claims and their equivalents.

Claims

1. A battery including a cell and a cover plate, The cell has at least one electrode body, each electrode body having a plurality of tabs; the cover plate has a tab protection piece on a surface facing the electrode body, The plurality of tabs are pulled out from the electrode body, bent, and gathered, and then extend onto the tab protection piece, and are welded to the tab protection piece to form a weld, and when the thickness direction of the electrode body and the surface of the cover plate on which the tab protection piece is arranged are perpendicular before the plurality of tabs are gathered and welded to the tab protection piece or after the electrode body is unfolded, the angle between the surface of the main body of the electrode body and the tab at the end of the main body of the electrode body from which the tab is pulled out is defined as the tab bending angle of the tab, The distance between the electrode body and the welding point is L １ The thickness of the electrode body is D, and the width of the tab protection piece in the extending direction of the tab is d １ and the tab bending angle of the tab is A; L １ =D / 2×|tanA|+d １ / 2、45°≦A≦135°、A≠90° A battery characterized by satisfying the following relational expression.

2. 2. The battery of claim 1, wherein a tab free area is formed between the electrode body and the weld point when the electrode body is parallel to the cover plate before being converged or after being deployed.

3. The electrode body is configured as a wound electrode body, and when the tab is pulled out from the electrode body in a tab half-pulling method, the thickness of the electrode body is D, and the length of the tab exposed from the electrode body in the extending direction of the tab is L. ２ and the length of the tab free area is L ３ and 0.25D<L ３ <L ２ 3. The battery according to claim 2, wherein the following relational expression is satisfied:

4. When the tab is fully pulled out from the electrode body, the thickness of the electrode body is D, and the length of the tab exposed from the electrode body in the extending direction of the tab is L. ２ and the length of the tab free area is L ３ and 0.5D<L ３ <L ２ 4. The battery according to claim 2, wherein the following relational expression is satisfied:

5. the plurality of tabs are converged to form tab converged lead-out positions, and the tab converged lead-out positions include a zero lead-out position, an intermediate lead-out position, and an eccentric lead-out position in the thickness direction of the electrode body, the zero lead-out position being located on an axis of the outermost layer of the main body of the electrode body, the intermediate lead-out position being located on a central axis of the main body of the electrode body, and the eccentric lead-out position being a position between the axis of the outermost layer of the main body of the electrode body and the central axis, 5. The battery according to claim 3, wherein the tab concentrated pull-out position is located at the zero pull-out position or the uneven pull-out position.

6. The plurality of tabs are converged to form a tab converged lead-out position, and the tab converged lead-out position includes a zero lead-out position, a middle lead-out position, and an eccentric lead-out position in a thickness direction of the electrode body; 5. The battery of claim 4, wherein the tab convergent pull-out position is located at the intermediate pull-out position.

7. 7. The battery according to claim 1, wherein the tab protection piece has a width of 8 to 12 mm.

8. The battery of any one of claims 1 to 7, characterized in that the weld point is disposed in a weld point region of the tab, the weld point region including an ultrasonic weld region and a laser weld region, and the laser weld region is located within the ultrasonic weld region.

9. 9. The battery according to claim 8, wherein the width of the ultrasonic welding area in the extending direction of the tab is 4 to 8 mm.

10. A battery pack comprising the battery according to any one of claims 1 to 9.

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