Battery cell and battery

Abstract

A battery cell and a battery. The battery cell comprises a body (100) and a first tab (200), wherein the body (100) comprises a first electrode sheet (110) and a second electrode sheet (120), the body is formed by winding the first electrode sheet (110) and the second electrode sheet (120), and the body (100) has a first end face (106) and a second end face, which are arranged opposite each other in a first direction; the first electrode sheet (110) has a plurality of bent portions and a plurality of straight portions from the inside out, the bent portions and the straight portions being alternately arranged; each straight portion is connected to a first dummy tab (113); after winding, the first dummy tabs (113) are stacked to form a conductive member, the conductive member protruding from the first end face (106); the first tab (200) is connected to the first electrode sheet (110) and protrudes from the first end face (106) or the second end face; and the conductive member is folded towards the body (100), and in the projection in the first direction, the projected area of the conductive member on the first end face (100) falls within the first end face (100). The battery cell enables the dimension of the dummy tabs in the direction of length to be reduced, thereby improving the energy density of the battery.

Description

Battery cell and battery TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy, in particular to a battery cell and a battery. BACKGROUND

[0002] In the winding battery cell, a plurality of false tabs and at least one true tab are arranged on the pole piece, and the winding false tabs are stacked together to shorten the moving distance of the current from different layers to the true tab during the charging and discharging process of the battery cell, thereby reducing the impedance of the current.

[0003] However, in the prior art, the false tab protrudes from the end face of the winding battery cell, thereby wasting a certain amount of inner space in the length direction of the battery, and further affecting the energy density of the battery.

[0004] SUMMARY

[0005] The present application aims to at least solve one of the technical problems in the prior art. To this end, the present application provides a battery cell capable of reducing the size of the false tab in the length direction, thereby improving the energy density of the battery.

[0006] The present application also provides a battery having the above battery cell.

[0007] The battery cell according to the first aspect of the present application comprises:

[0008] a main body comprising a first pole piece and a second pole piece, the main body being formed by winding the first pole piece and the second pole piece, the main body having a first end face and a second end face oppositely arranged along a first direction, the first pole piece having a plurality of bending portions and a plurality of straight portions from inside to outside, the bending portions and the straight portions being alternately arranged, each of the straight portions being connected with a first false tab, the first false tab being stacked to form a conductive member after winding, the conductive member being protrudingly arranged on the first end face;

[0009] at least one first tab connected to the first pole piece and protrudingly arranged on the first end face or the second end face;

[0010] wherein the conductive member is folded towards the main body, and the projection of the conductive member on the first end face falls within the first end face along the projection in the first direction.

[0011] The battery cell according to the present application has at least the following beneficial effects:

[0012] In the present application, the first conductive member is folded towards the main body, more specifically, the first conductive member is folded along the thickness direction of the battery cell main body, so as to reduce the length of the first conductive member along the first direction, thereby leaving more space for accommodating the battery cell main body, so as to further improve the energy density of the battery. Moreover, after folding, the projection of the first conductive member on the first end surface falls within the first end surface along the first direction, that is, the length of the folded first conductive member along the thickness direction of the battery cell main body is less than the thickness of the battery cell main body, so as to be arranged without protruding from the side surface of the battery cell main body, so as to avoid occupying the space along the thickness direction in the battery case.

[0013] According to some embodiments of the present application, the conductive member includes a first conductive member and a second conductive member, the first false tabs of adjacent coil layers are staggered, part of the first false tabs are stacked to form the first conductive member, and the remaining first false tabs are stacked to form the second conductive member.

[0014] According to some embodiments of the present application, the first false tabs of adjacent coil layers are correspondingly arranged, each of the first false tabs is set to be stacked to form the first conductive member, each of the linear portions is further connected with a second false tab, the first false tabs and the second false tabs are alternately arranged along the length direction of the first tab, and each of the second false tabs is stacked to form a second conductive member after winding.

[0015] According to some embodiments of the present application, the first conductive member and the second conductive member are bent in the same direction, or the first conductive member and the second conductive member are bent in opposite directions.

[0016] According to some embodiments of the present application, the directions in which the second conductive member and the first conductive member protrude from the main body are the same.

[0017] According to some embodiments of the present application, the first false tab and the second false tab connected with the same linear portion are set as a group, and the distances between the first false tabs and the second false tabs of each group are equal.

[0018] According to some embodiments of the present application, the main body further includes a first surface and a second surface arranged in parallel along the thickness direction, the first conductive member is bent towards the first surface, and the length of each of the first false tabs in the first conductive member gradually decreases along the direction from the second surface to the first surface.

[0019] According to some embodiments of the present application, the battery cell further includes at least one second tab, the second tab is connected with the second tab, and the second tab and the first tab both protrude from the second end surface.

[0020] According to some embodiments of the present application, the first tab is connected with the first pole piece at a head end or at a tail end of the first pole piece in a winding direction of the first pole piece.

[0021] According to some embodiments of the present application, the first conductive member is bonded with the main body.

[0022] The battery according to the second aspect of the embodiments of the present application comprises the battery cell according to any one of the above embodiments.

[0023] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0024] The present application will be further described below in conjunction with the drawings and embodiments, wherein:

[0025] Fig. 1 is a schematic structural view of a battery cell according to an embodiment of the present application;

[0026] Fig. 2 is a simplified schematic view of the battery cell according to an embodiment of the present application after being wound and formed;

[0027] Fig. 3 is a schematic structural view of a pole piece according to an embodiment of the present application in an unfolded state;

[0028] Fig. 4 is an enlarged schematic view of region A in Fig. 2.

[0029] Reference Signs:

[0030] Main body 100; first conductive member 101; second conductive member 102; first surface 103; arc-shaped section 104; straight section 105; first end surface 106;

[0031] First pole piece 110; bending portion 111; straight portion 112; first dummy tab 113; second dummy tab 114; head end 115; tail end 116; second pole piece 120;

[0032] First tab 200; second tab 250. DETAILED DESCRIPTION

[0033] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0034] In the description of the present application, it needs to be understood that the orientation description, such as the orientation or position relationship indicated by the upper, lower, front, rear, left, right and the like, is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0035] In the description of the present application, if the meaning of several is more than one, the meaning of multiple is more than two, greater than, less than, more than and the like are understood as not including the number, above, below, within and the like are understood as including the number. If it is described as first, second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0036] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting and the like should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0037] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific 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 present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0038] In the winding electrode core, a plurality of false tabs and at least one true tab are arranged on the electrode tab, and the false tabs after winding are stacked together to shorten the moving distance of the current from different layers to the true tab during the charging and discharging process of the electrode core, thereby reducing the impedance of the current.

[0039] However, in the prior art, the false tab is arranged protruding from the end face of the wound electrode core, thereby wasting a certain inner space in the length direction of the battery, thereby affecting the energy density of the battery.

[0040] To solve the above problems, the application provides an electric core, which comprises a main body 100 and at least one first tab 200, the main body 100 comprises a first tab 110 and a second tab 120, the first tab 110, a diaphragm and the second tab 120 are wound to form the main body 100 of the electric core, in the embodiment shown in FIG. 1, the main body 100 is a racetrack type, and two arc-shaped sections 104 are arranged on both sides of the main body 100 in the width direction, and the two arc-shaped sections 104 are connected by a straight section 105. The main body 100 of the electric core has a first end face 106 and a second end face 106 arranged oppositely in the first direction, that is, two end faces of the main body 100 in the length direction.

[0041] It should be understood that, as shown in FIGS. 2 and 3, the first tab 110 and the second tab 120 before winding are both long strip structures, and have a head end 115 and a tail end 116, winding is started from the head end 115 and is ended at the tail end 116, so as to form a winding structure. After winding to form the main body 100, the first tab 110 has a plurality of bending portions 111 and a plurality of straight portions 112 from inside to outside, and the bending portions 111 and the straight portions 112 are arranged alternately. Each bending portion 111 is arranged layer by layer to form the arc-shaped section 104 of the main body 100, and each straight portion 112 is arranged layer by layer to form the straight section 105 of the main body 100. Before winding, the length of each bending portion 111 and each straight portion 112 can be determined by calculation.

[0042] Each straight portion 112 is connected with at least one first dummy tab 113, the first dummy tab 113 is stacked to form a conductive part after winding, and the conductive part is protruded from the first end face. Specifically, the stacking of the first dummy tab 113 after winding of the first tab 110 presents the following two cases according to the different setting positions of the first dummy tab 113 on the first tab 110.

[0043] In some embodiments, the first dummy tab 113 of the adjacent coil layer is arranged correspondingly during winding, so that each first tab 200 is stacked together after winding, and then an integral part is formed by welding, bonding or other connecting methods, and the foregoing integral part is named as a first conductive part 101 for the convenience of subsequent description. It can be understood that, since the first dummy tab 113 is protruded from the first tab 110, the first conductive part 101 after winding and stacking is protruded from the first end face 106 of the main body 100. In the embodiment shown in FIG. 3, a second dummy tab 114 is further arranged, and in other embodiments, a third dummy tab, a fourth dummy tab or the like can also be arranged. It should be understood that, the structure and length of the first dummy tab 113 and the second dummy tab 114 can be similar or not similar,

[0044] In some embodiments, the first dummy tab 113 of adjacent layers is staggered during winding, so that the first dummy tab 113 of the later layers is stacked to form the first conductive member 101, and the first dummy tab 113 of the remaining layers is stacked to form the second conductive member 102, thereby reducing the thickness of the single conductive member.

[0045] The first tab 200 is connected to the first tab 110 at one end, and is used to connect with the pole of the top cover of the battery, thereby being used to input or output current. As shown in FIG. 1 and FIG. 3, the first tab 200 and the first dummy tab 113 are arranged on different sides of the first tab 110 along the width direction of the first tab 110, so that the first tab 200 and the first conductive member 101 are located at different ends of the main body 100 after winding, that is, the first conductive member 101 protrudes from the first end surface 106, and the first tab 200 protrudes from the second end surface. Therefore, during the manufacturing process of the first tab 110, the distance and size of the die cutting of the edge of the first tab 110 to form the first dummy tab 113 are relatively uniform, so that the die cutting process is relatively simple. In some embodiments, the first tab 200 can also be arranged on the second end surface, so as to be located on the same end surface as the first conductive member 101.

[0046] Taking the head end 115 of the first tab 200 connected to the first tab 110 as an example, when the battery outputs current, if the first dummy tab 113 is not arranged, the current of the tail end 116 of the first tab 110 needs to flow through the entire first tab 110, and then be output from the first tab 200 at the head end 115, so that the impedance of the battery is high. In the present application, since the first dummy tab 113 is arranged and stacked to form the first conductive member 101, the current of the inner and outer layers can be directly transmitted to the layer where the first tab 200 is located through the first conductive member 101, thereby greatly shortening the transmission path of the current and reducing the impedance of the battery.

[0047] It should be noted that since the first conductive member protrudes from the first end surface 106, if it is not processed, the first conductive member extends in the first direction, thereby occupying a large space in the battery shell, causing the space for accommodating the main body 100 to be less, thereby reducing the energy density of the battery. In the present application, as shown in FIG. 2 and FIG. 4, the first conductive member 101 is folded towards the main body 100, more specifically, the first conductive member 101 is folded along the thickness direction of the main body 100, thereby reducing the length of the first conductive member 101 in the first direction, thereby leaving more space for accommodating the main body 100 of the battery cell, thereby further improving the energy density of the battery.

[0048] And, after folding, the projection of the first conductive member 101 on the first end surface 106 in the first direction falls within the first end surface 106, that is, the length of the first conductive member 101 in the thickness direction of the main body 100 after folding is less than the thickness of the main body 100 of the battery cell, so that the first conductive member 101 does not protrude from the side surface of the main body 100, thereby avoiding occupying the space in the thickness direction of the battery case.

[0049] In some embodiments, as shown in FIGS. 1-3, each straight portion 112 is further connected with a second dummy tab 114, and in the unfolded state of the first tab 200 (i.e., the state before winding), the first dummy tab 113 and the second dummy tab 114 are arranged alternately along the length direction of the first tab 110. It should be noted that each second dummy tab 114 is stacked to form a second conductive member 102 after winding, and the first conductive member 101 and the second conductive member 102 are arranged in a spaced manner, so that the first conductive member 101 and the second conductive member 102 can both shorten the current transmission path.

[0050] Further, the first conductive member 101 and the second conductive member 102 are both bent in the same direction. For example, in the embodiment shown in FIGS. 1 and 2, the first conductive member 101 and the second conductive member 102 are both bent upward, and the first conductive member 101 and the second conductive member 102 after bending are arranged not to protrude from the upper surface of the main body 100 of the battery cell. Alternatively, the first conductive member 101 and the second conductive member 102 can also be bent downward. It can be understood that the bending directions of the first conductive member 101 and the second conductive member 102 are consistent, which is beneficial to improve the consistency of the process flow. In some further embodiments, the folding of the first conductive member 101 and the second conductive member 102 can be realized simultaneously by the same folding mechanism.

[0051] In other embodiments, the first conductive member 101 and the second conductive member 102 can also be bent in opposite directions, for example, one of the conductive members is bent upward and the other conductive member is bent downward.

[0052] Based on the foregoing embodiments, the first conductive member 101 and the first tab 200 are respectively located at two ends of the main body 100, and the first conductive member 101 is located on the first end surface 106. Preferably, as shown in FIGS. 1-3, the second conductive member 102 is also arranged on the first end surface 106. That is, in the unfolded state of the first tab 110, the first dummy tab 113 and the second dummy tab 114 are arranged on the same side of the first tab 110. Since the structure and arrangement position of the first dummy tab 113 and the second dummy tab 114 are regular, the process is relatively simple when the first dummy tab 113 and the second dummy tab 114 are die-cut and formed, avoiding the interference of the first tab 200.

[0053] In some embodiments, as shown in FIG. 3, the first dummy tab 113 and the second dummy tab 114 connected to the same straight part 112 are set as a group, that is, the first dummy tab 113 and the second dummy tab 114 on the same straight part 112 are set as a group. It can be understood that each straight part 112 is provided with a first dummy tab 113 and a second dummy tab 114, and the distance between the first dummy tab 113 and the second dummy tab 114 in each group is equal. It can be understood that, since the circumference gradually increases when winding from inside to outside, the arc length of the bending part 111 of different layers is not equal, and the length of the straight part 112 is equal. The positions of the first dummy tab 113 and the second dummy tab 114 on each straight part 112 are the same, so that the first dummy tab 113 of the straight part 112 can be stacked with the first dummy tab 113 of the inner layer after each winding, and the second dummy tab 114 is the same.

[0054] In some embodiments, the main body 100 further comprises a first surface 103 and a second surface arranged in parallel along the thickness direction. In the embodiment shown in FIG. 2, the first surface 103 is the upper surface, and the second surface is the lower surface. In other embodiments, the first surface 103 can also be the lower surface, and the second surface is the upper surface. The first conductive part 101 is bent towards the first surface 103, and the second conductive part 102 is also bent towards the first surface 103. Among them, in the direction from the second surface to the first surface 103, the length of each first dummy tab 113 in the first conductive part 101 gradually decreases.

[0055] It can be understood that, taking the embodiment shown in FIG. 4 as an example, if the length of each first dummy tab 113 in the first conductive part 101 is consistent, the first dummy tab 113 at the uppermost end is most likely to protrude from the first surface 103 of the main body 100 during the upward bending process. In the direction from top to bottom, the probability of each first dummy tab 113 protruding from the first surface 103 gradually decreases. Therefore, in the embodiment shown in FIG. 4, the lengths of each first dummy tab 113 are set to be different, which can reduce the risk of the uppermost first dummy tab 113 protruding from the first surface 103 after bending, and avoid occupying additional space of the battery along the width direction. It should be noted that the length of the lowermost first dummy tab 113 along the width direction after bending should be less than or equal to the width of the main body 100.

[0056] In some embodiments, the battery cell further comprises at least one second tab 250 connected to the second tab 120. It can be understood that the number of the first tab 200 and the second tab 250 can be one or multiple, which can be adjusted according to specific design requirements. In the embodiments as shown in FIGS. 1-3, for the convenience of connecting with the pole of the shell, the first tab 200 and the second tab 250 are both protruded on the second end face, so that the pole can also be arranged on the same end face of the battery shell corresponding to the second end face, which is conducive to the connection with the external circuit. Alternatively, the first tab 200 and the second tab 250 are both protruded on the first end face, so as to ensure that the first tab 200 and the second tab 250 are arranged in the same position.

[0057] It should be noted that the second tab 120 can also be provided with a false tab structure as the first tab 110, so as to shorten the current transmission path on the second tab 120. The structure of the second tab 120 can be similar to that of the first tab 110, which will not be described here.

[0058] In some embodiments, the first tab 200 is connected to the head end 115 of the first tab 110, in other embodiments, the first tab 200 is connected to the tail end 116 of the first tab 110, and in some embodiments, the first tab 200 is connected to the middle part of the first tab 110, i.e. the region between the head end 115 and the tail end 116. The second tab 250 can also be connected to the head end 115, the tail end 116 or the middle part of the second tab 120. It can be understood that the first tab 200 and the second tab 250 need to be staggered in the thickness direction of the main body 100 to avoid short circuit caused by electrical conduction of the first tab 200 and the second tab 250.

[0059] In some embodiments, the first conductive member 101 needs to be bonded with the main body 100 after being bent. It can be understood that, taking the upward bending of the first conductive member 101 as shown in FIG. 4 as an example, since each first false tab 113 in the first conductive member 101 has been welded together to form an integral structure, the adhesive can be applied to the inner side of the first conductive member 101 close to the first end face 106 after being bent, so as to connect the first conductive member 101 with the main body 100, avoiding the rebound of the first conductive member 101 after being bent. Alternatively, a layer of adhesive paper can also be attached to the outer side of the first conductive member 101 away from the first end face 106 after being bent, so as to connect the first conductive member 101 with the main body 100.

[0060] The second aspect embodiment of the present application proposes a battery, which comprises the battery cell mentioned in any of the above embodiments.

[0061] The embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. An electric cell, characterized by, The electric core comprises: a main body comprising a first pole piece and a second pole piece, the main body being formed by winding the first pole piece and the second pole piece, the main body having a first end face and a second end face oppositely arranged along a first direction, the first pole piece having a plurality of bending portions and a plurality of straight portions from inside to outside, the bending portions and the straight portions being alternately arranged, each of the straight portions being connected with a first dummy tab, the first dummy tabs being stacked to form a conductive member after winding, the conductive member being protruded on the first end face; at least one first tab connected with the first pole piece and protruded on the first end face or the second end face; wherein the conductive member is folded towards the main body, and the projection of the conductive member on the first end face falls within the first end face along the projection in the first direction.

2. The electric cell of claim 1, wherein, The conductive member comprises a first conductive member and a second conductive member, the first dummy tabs of adjacent coil layers being staggered, part of the first dummy tabs being stacked to form the first conductive member, and the rest of the first dummy tabs being stacked to form the second conductive member.

3. The electric cell of claim 1, wherein, The first dummy tabs of adjacent coil layers are correspondingly arranged, each of the first dummy tabs being set to form the first conductive member, each of the straight portions further being connected with a second dummy tab, the first dummy tabs and the second dummy tabs being alternately arranged along the length direction of the first pole piece, each of the second dummy tabs being stacked to form a second conductive member after winding.

4. The electric cell of claim 3, wherein, The first conductive member and the second conductive member are bent in the same direction, or the first conductive member and the second conductive member are bent in opposite directions.

5. The electric cell of claim 3, wherein, The second conductive member and the first conductive member are arranged on the first end face.

6. The electric cell of claim 3, wherein, The first dummy tabs and the second dummy tabs connected with the same straight portion are set as a group, and the distance between the first dummy tabs and the second dummy tabs of each group is equal.

7. The electric cell of claim 1, wherein, The main body further comprises a first surface and a second surface arranged in parallel along the thickness direction, the conductive member being folded towards the first surface, and the length of each of the first dummy tabs in the conductive member gradually decreasing along the direction from the second surface to the first surface.

8. The electric cell of claim 1, wherein, The electric core further comprises at least one second tab connected with the second pole piece, and the second tab and the first tab protrude in the same direction of the main body.

9. The electric cell of claim 1, wherein, Along the winding direction of the first pole piece, the first pole piece has a head end and a tail end in sequence, the first tab being connected with the first pole piece at the head end, or the first tab being connected with the first pole piece at the tail end, or the first tab being connected with the first pole piece at a region between the head end and the tail end.

10. The electric cell of claim 1, wherein, The conductive member is bonded with the main body.

11. A battery characterized by The electric core comprises the electric core according to any one of claims 1 to 10.

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