Cell and secondary battery

Abstract

The utility model provides a battery cell and a secondary battery. Wherein the battery cell comprises a plurality of layers of pole pieces which are formed by overlapping along the thickness direction of the battery cell; one side of each layer of pole piece is provided with one pole lug, at least part of the pole lugs are overlapped in the thickness direction of the battery cell, and the direction of the pole lugs protruding out of the pole pieces is the height direction of the battery cell; the direction perpendicular to the height direction of the battery cell and the thickness direction of the battery cell is the width direction of the battery cell, and the stacked tabs comprise side tabs located on the two sides of the stacking direction and a middle tab located between the side tabs; and in the width direction of the battery cell, the width of the middle tab is greater than that of the side tabs. According to the utility model, the problems of low over-current capability of the battery and large internal resistance of the battery caused by high tab height in the prior art are solved.

Description

Technical Field

[0001] The utility model relates to the field of batteries, and in particular to a battery core and a secondary battery. Background Art

[0002] An important step in the traditional secondary battery assembly process is to ultrasonically weld the copper tabs and aluminum tabs on the winding core to the copper adapter and aluminum adapter respectively, and then the adapter is laser welded to the top cover electrode. The number of positive and negative tabs of traditional secondary batteries is only half of the number of positive and negative electrode sheets, which will result in low current capacity of the battery and high internal resistance. If the number of positive and negative tabs of the battery is equal to the number of positive and negative electrode sheets, then the battery cell and the adapter are usually welded to all the positive tabs (or all the negative tabs) and the adapter. Due to the excessive number of tabs, the required tab height for welding is higher, the cell capacity per unit volume is low, the risk of tab sinking is greater, and the manufacturing cost is greatly increased. Utility Model Content

[0003] The main purpose of the utility model is to provide a battery cell and a secondary battery to solve the problem in the prior art that the high height of the tab leads to large internal resistance of the battery.

[0004] In order to achieve the above-mentioned purpose, according to one aspect of the utility model, a battery cell is provided, comprising: a plurality of layers of pole sheets stacked along the thickness direction of the battery cell; a plurality of pole ears, each layer of pole sheets is provided with a pole ear on one side, and at least part of the pole ears are stacked in the thickness direction of the battery cell, and the direction in which the pole ears protrude from the pole sheets is the height direction of the battery cell; the direction perpendicular to the height direction of the battery cell and also perpendicular to the thickness direction of the battery cell is the width direction of the battery cell, and the stacked pole ears include side pole ears located on both sides of the stacking direction and middle pole ears located between the side pole ears; in the width direction of the battery cell, the width of the middle pole ears is greater than the width of the side pole ears.

[0005] It can be understood that the battery cell usually includes a laminated battery cell and a wound core. No matter it is laminated or wound, a plurality of stacked pole pieces will always be formed along the thickness direction of the battery cell; that is, the battery cell in the present application can be a laminated battery cell or a wound core.

[0006] Further, along the stacking direction of the electrode tabs, the orthographic projection of the side electrode tab on the surface of the middle electrode tab is located within the range of the middle electrode tab.

[0007] Furthermore, along the width direction of the battery cell, both ends of the middle pole ear extend out of the ends of the side pole ears, and in the width direction of the battery cell, except for the middle pole ear, the remaining multiple pole ears have the same width.

[0008] Furthermore, in the height direction of the battery cell, the height of the middle pole lug is less than or equal to the height of the side pole lug.

[0009] Furthermore, all the electrode tabs include positive electrode tabs and negative electrode tabs, the positive electrode tabs are stacked on each other, the negative electrode tabs are stacked on each other, and both the positive electrode tabs and the negative electrode tabs include an intermediate electrode tab.

[0010] According to another aspect of the utility model, a secondary battery is provided, comprising: the above-mentioned battery cell, in which a mounting area is formed between an intermediate pole ear and a pole ear adjacent to the intermediate pole ear, wherein a side pole ear at which the pole ear that forms the mounting area with the intermediate pole ear is located is set as a first side pole ear, and the other side pole ear is set as a second side pole ear; a transfer plate, the transfer plate is located in the mounting area; the first side pole ear bypasses one side edge of the transfer plate and is connected to an upper surface of the transfer plate; the second side pole ear and the intermediate pole ear bypass the other side edge of the transfer plate and are connected to an upper surface of the transfer plate.

[0011] It can be understood that the upper surface of the adapter refers to the surface of the adapter facing away from the battery cell (ie, the surface facing the top cover).

[0012] Furthermore, there are multiple battery cells, and the adapter is located in the installation areas of the multiple battery cells at the same time, and connects the tabs of the same polarity in the multiple battery cells together.

[0013] Furthermore, the adapter includes a main body and a plurality of contact portions arranged at intervals, each contact portion is connected to the main body, and each contact portion is located in an installation area formed by pole tabs of the same polarity in different battery cells, and is used to connect to pole tabs of the same polarity in different battery cells.

[0014] Furthermore, each contact portion is connected to a pole ear of a battery cell; in each battery cell, the first side pole ear bypasses one side of the contact portion and is connected to the upper surface of the contact portion; the second side pole ear and the middle pole ear bypass the other side of the contact portion and are connected to the upper surface of the contact portion.

[0015] Furthermore, the adapter has a first pole, and the secondary battery also includes a top cover, which is arranged on the pole piece of the battery cell, the pole ear and the adapter are located in the top cover, and the top cover has a second pole, and the first pole is in contact with the second pole.

[0016] Furthermore, the tab of the battery cell has a welding mark, and the welding mark is located on the surface of the tab forming the mounting area and the surface away from the mounting area, and the tab is welded to the adapter sheet through the welding mark.

[0017] By applying the technical solution of the utility model, the pole ears are divided into side pole ears and middle pole ears, and the width of the middle pole ears is larger than that of the side pole ears. Therefore, during welding, the stacked pole ears can be conveniently divided into two parts from the position of the middle pole ears, so that the two parts of the pole ears can be conveniently matched with the adapter. Specifically, when the battery cell is processed into a secondary battery, the side pole ears on both sides can be bent away from each other through the middle pole ears, and the middle pole ears can be bent together with the side pole ears on either side, so that an installation area is formed in the middle of the pole ears, and then the adapter can be installed in the installation area, and then the pole ears are further bent so that the pole ears can contact and weld with the adapter. After the adapter is installed, the top cover is installed on the adapter, and the adapter and the top cover are sealed and welded together by laser, so that a secondary battery can be formed. Based on the structural form of the battery cell of the utility model, since the pole ears are divided into two parts, the number of pole ears in each part will not be too many during welding; therefore, the height of the pole ears can be reduced by cooperating with the above-mentioned assembly process, and the distance from the top surface of the battery cell to the plastic under the top cover can be reduced, thereby increasing the battery cell capacity per unit volume, reducing the risk of pole ear sinking, reducing the internal resistance of the battery cell, and reducing the manufacturing cost. In addition, the number of pole sheet layers and the number of pole ears of the battery cell of the utility model are equal, and the battery's overcurrent capacity will not be low. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0019] Figure 1 The structure diagram of the battery cell of the first embodiment of the utility model is shown;

[0020] Figure 2 The schematic diagram of the structure of the battery cell after ultrasonic welding of the first embodiment is shown;

[0021] Figure 3 The figure shows a schematic structural diagram of the battery cell and the adapter sheet after welding in the first embodiment;

[0022] Figure 4 The schematic diagram of the structure after the battery cell and the top cover are welded in the first embodiment is shown;

[0023] Figure 5 It shows a schematic structural diagram of the two battery cells and the adapter after welding in the second embodiment;

[0024] Figure 6 It shows a schematic structural diagram of a secondary battery formed by assembling two battery cells and a top cover in the second embodiment;

[0025] Figure 7The schematic diagram of the structure after welding three battery cells and the adapter sheet of the second embodiment is shown;

[0026] Figure 8 The schematic diagram of the structure after welding the four battery cells and the adapter sheet of the second embodiment is shown.

[0027] The above drawings include the following reference numerals:

[0028] 10. Pole piece; 20. Pole ear; 21. Middle pole ear; 22. Side pole ear; 221. Welding mark; 30. Adapter; 31. Main body; 311. First pole; 32. Contact part; 40. Top cover; 41. Second pole; 50. Battery cell. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present utility model will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0030] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0031] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0032] In order to solve the problem in the prior art that the high height of the tab leads to large internal resistance of the battery, the utility model provides a battery cell and a secondary battery.

[0033] It should be noted that, in order to facilitate the understanding of the technical solution of the utility model, Figure 1 As shown in the figure, the thickness direction of the battery cell in the utility model is as follows Figure 1 The X direction in the cell height direction is Figure 1 The Z direction in the cell width direction is Figure 1 in the Y direction.

[0034] Embodiment 1

[0035] like Figure 1A battery cell shown includes a plurality of electrode sheets 10 and a plurality of electrode tabs 20 stacked in the thickness direction of the battery cell, a electrode tab 20 is provided on one side of each layer of electrode sheets 10, and at least part of the electrode tabs 20 are stacked in the thickness direction of the battery cell, and the direction in which the electrode tabs 20 protrude from the electrode sheets 10 is the height direction of the battery cell; the direction perpendicular to the height direction of the battery cell and also perpendicular to the thickness direction of the battery cell is the width direction of the battery cell; the stacked electrode tabs 20 include side electrode tabs 22 located on both sides of the stacking direction and a middle electrode tab 21 located between the side electrode tabs 22; in the width direction of the battery cell, the width of the middle electrode tab 21 is greater than the width of the side electrode tabs 22.

[0036] In this embodiment, the pole ear 20 is divided into a side pole ear 22 and a middle pole ear 21, and the width of the middle pole ear 21 is larger than the width of the side pole ear 22, so that when welding, the stacked pole ear 20 can be conveniently divided into two parts from the position of the middle pole ear 21, so that the two parts of the pole ear 20 can be conveniently matched with the adapter 30. Specifically, when the battery cell 50 is processed into a secondary battery, the side pole ears 22 on both sides can be bent away from each other through the middle pole ear 21, and the middle pole ear 21 can be bent together with the side pole ears 22 on either side, so that an installation area is formed in the middle of the pole ear 20, and then the adapter 30 can be installed in the installation area, and then the pole ear 20 is further bent so that the pole ear 20 can contact and weld with the adapter 30. After the adapter 30 is installed, the top cover 40 is installed on the adapter 30, and the adapter 30 and the top cover 40 are sealed and welded together by laser, so that a secondary battery can be formed. Based on the structural form of the battery cell 50 of the present embodiment, since the pole ear 20 is divided into two parts, the number of pole ears in each part will not be too many during welding; therefore, the height of the pole ear can be reduced by cooperating with the above-mentioned assembly process, and the distance from the top surface of the battery cell to the plastic under the top cover can be reduced, thereby increasing the battery cell capacity per unit volume, reducing the risk of pole ear sinking, reducing the internal resistance of the battery cell, and reducing the manufacturing cost. In addition, the number of pole sheet layers and the number of pole ears of the battery cell of the present embodiment are equal, and the battery's overcurrent capacity will not be low.

[0037] In this embodiment, along the stacking direction of the tabs 20, the orthographic projection of the side tabs 22 on the surface of the middle tabs 21 is located within the range of the middle tabs 21. In other words, the side tabs 22 are always located within the width range of the middle tabs 21 and will not exceed the width boundary of the middle tabs 21, so that the middle tabs 21 can play a stable and reliable partitioning role for the side tabs 22 during the subsequent processing of the battery cell 50, and the reliability of the tabs 20 being bent into two parts to form the installation area can be ensured.

[0038] Furthermore, along the width direction of the battery cell, both ends of the middle pole ear 21 extend beyond the ends of the side pole ear 22; and in the width direction of the battery cell, except for the middle pole ear 21, the remaining multiple pole ears 20 have the same width. That is to say, along the width direction of the battery cell, there is always a certain distance between the orthographic projection boundary of the side pole ear 22 on the surface of the middle pole ear 21 and the side boundary of the corresponding side of the middle pole ear 21, so that both ends of the width of the middle pole ear 21 exceed the end boundary of the side pole ear 22, so that the pole ears 20 can be bent in sections from both ends of the middle pole ear 21. In addition, except for the middle pole ear 21, the remaining multiple pole ears 20 have the same width, which can reduce the process difficulty of pole piece die cutting.

[0039] Of course, in addition to the above-mentioned setting method, the orthographic projection of the side pole ear 22 may also be only partially within the range of the middle pole ear 21. In this case, the middle pole ear 21 does not cover the entire side of the side pole ear 22, or even if the orthographic projection of the side pole ear 22 is completely within the range of the middle pole ear 21, a setting method in which a width boundary of the middle pole ear 21 coincides with the width boundary of the side pole ear 22 can be adopted. The specific setting can be selected according to needs, as long as the width of the middle pole ear 21 is greater than the width of the side pole ear 22.

[0040] In this embodiment, in the height direction of the battery cell, the height of the middle pole tab 21 is less than or equal to the height of the side pole tab 22 .

[0041] Considering the use requirements of the battery cell 50, the electrode sheet 10 of this embodiment includes a positive electrode sheet and a negative electrode sheet. Accordingly, all the pole ears 20 include a positive pole ear connected to the positive pole sheet and a negative pole ear connected to the negative pole sheet. The positive pole ear and the negative pole ear are respectively located on both sides of the battery cell 50, wherein the structural forms of the positive pole ear and the negative pole ear can be relatively independently arranged, and only one of them can adopt the arrangement mode of this embodiment, or both can adopt the arrangement mode of this embodiment. This embodiment adopts the latter arrangement mode, that is, the positive pole ears are stacked on each other, and the negative pole ears are stacked on each other, and both the positive pole ears and the negative pole ears include an intermediate pole ear 21, and both adopt the arrangement mode between the intermediate pole ear 21 and the side pole ear 22.

[0042] like Figure 3 and Figure 4As shown, this embodiment also provides a secondary battery, including the aforementioned battery cell 50 and adapter 30, in which a mounting area is formed between the middle pole ear 21 and the pole ear 20 adjacent to the middle pole ear 21, wherein the side pole ear 22 where the pole ear 20 forming the mounting area with the middle pole ear 21 is located is set as the first side pole ear, and the other side pole ear 22 is set as the second side pole ear; the adapter 30 is located in the mounting area, the first side pole ear bypasses one side of the adapter 30 and is connected to the upper surface of the adapter 30; the second side pole ear and the middle pole ear 21 bypass the other side of the adapter 30 and are connected to the upper surface of the adapter 30. The processing and assembly of the secondary battery is achieved by the cooperation between the adapter 30 and the pole ear 20 of the battery cell 50.

[0043] In this embodiment, only one battery cell 50 is provided, so the adapter 30 only needs to be connected to the positive electrode tab or the negative electrode tab of the battery cell 50 for conduction.

[0044] The adapter 30 of this embodiment has a first pole 311, and the secondary battery also includes a top cover 40, which is covered on the pole piece 10 of the battery cell 50, the pole ear 20 and the adapter 30 are located in the top cover 40, and the top cover 40 has a second pole 41, and the first pole 311 is in contact with the second pole 41.

[0045] like Figure 2 As shown in the figure, when assembling the battery cell 50, the adapter 30 and the top cover 40, the middle pole ear 21 is used as the boundary, and an external force is applied to the middle pole ear 21, so that the pole ears 20 of the battery cell 50 are layered from the middle pole ear 21. Specifically, the side pole ears 22 on both sides are respectively gathered to both sides of the battery cell 50 along the thickness direction of the battery cell, that is, the middle pole ear 21 and one of the side pole ears 22 form a whole, and the other side pole ear 22 forms a whole. In this way, the installation area is avoided between the middle pole ear 21 and the other side pole ear 22, so that two parts of the pole ears 20 arranged opposite to each other at the edge of the battery cell 50 are formed, and the two parts of the pole ears 20 are respectively welded to the adapter, thereby greatly reducing the thickness of the pole ears 20 welded to the adapter. In addition, the adapter sheet 30 is placed in the installation area, and the two parts of the tabs 20 are bent close to the adapter sheet 30, and folded on the upper surface of the adapter sheet 30, and welded to the adapter sheet 30. The adapter sheet 30 is provided with a first pole 311, and the top cover 40 is provided with a second pole 41. The top cover 40 is provided on the tab 20 and the upper part of the adapter sheet 30, and the first pole 311 and the second pole 41 are in contact and conductive. Since the tab 20 is divided into positive and negative poles, the first pole 311 and the second pole 41 are also provided in plurality and are divided into positive and negative poles, and the positive and negative poles are respectively provided corresponding to the positive and negative poles of the tab 20.

[0046] It should be noted that the battery cell 50 of this embodiment can adopt a winding core, so the electrode sheet 10 is divided into a positive electrode sheet and a negative electrode sheet, a diaphragm is arranged between the positive electrode sheet and the negative electrode sheet, and the electrode sheet 10 and the diaphragm are wound into shape; in the thickness direction of the battery cell 50, a battery cell 50 containing multiple layers of electrode sheets 10 stacked on each other is formed. The adapter sheet 30 of this embodiment is divided into an aluminum adapter sheet and a copper adapter sheet, the positive electrode ear cooperates with the aluminum adapter sheet, and the negative electrode ear cooperates with the copper adapter sheet. Of course, the battery cell can also be other types of battery cells, such as laminated battery cells, and the form, position, etc. of the middle electrode ear 21 and the side electrode ear 22 are basically the same as the setting method of the winding core of this embodiment.

[0047] like Figure 2 As shown, during the assembly process of the pole lug 20 and the adapter sheet 30, the pole lug 20 in this embodiment includes a first section and a second section connected in sequence when bent obliquely, the first section is bent and connected to the pole sheet 10, the second section is bent and connected to the first section, the second section extends along the height direction of the battery cell, and the second sections of each obliquely bent pole lug 20 are overlapped, so as to form an installation area between the pole lugs 20, and then the adapter sheet 30 is placed in the installation area, and then the second section is bent and folded on the upper surface of the adapter sheet 30, and then welded.

[0048] The pole tab 20 in this embodiment has a weld mark 221, and the weld mark 221 is located on the surface of the pole tab 20 forming the installation area and the surface away from the installation area, that is, after the side pole tab 22 is bent and gathered, the ends of each pole tab 20 are overlapped with each other, and the pole tab 20 is ultrasonically welded, leaving the weld mark 221 on the surface of the overlapping area to strengthen the connection of the pole tab 20 and make it a conductor. The side pole tab 22 is welded to the adapter plate 30 through the weld mark 221.

[0049] It should be noted that, since the pole tab 20 includes a positive pole tab and a negative pole tab, and the middle pole tab 21 divides the side pole tab 22 into two parts, and each side pole tab is welded to the adapter 30 respectively, a battery cell 50 should have four welding areas between the pole tab 20 and the adapter 30.

[0050] The specific assembly process of the secondary battery of this embodiment is as follows: a single battery cell 50 is formed by winding the negative electrode sheet, the positive electrode sheet, and the separator between the positive and negative electrode sheets together through a winding needle. Each layer of the positive and negative electrode sheets corresponds to a positive and negative electrode ear, respectively. The negative electrode ear (usually copper foil) is located on the edge of the negative electrode sheet, and the positive electrode ear (usually aluminum foil) is located on the edge of the positive electrode sheet. The negative electrode ear located in the middle of the battery cell 50 is wider than the other negative electrode ears, and the other negative electrode ears are of equal size. The positive electrode ear located in the middle of the battery cell 50 is wider than the other positive electrode ears, and the other positive electrode ears are of equal size. Figure 2As shown, with the positive and negative wide tabs located in the middle of the battery cell 50 as the reference, the positive and negative tabs are bent to both sides to form a mounting area, and then the adapter 30 can be installed in the mounting area, and then the tab 20 is further bent so that the tab 20 can contact and weld with the adapter 30. Specifically, as Figure 3 As shown, the battery cell 50 is welded together with the copper adapter and the aluminum adapter, and the positive and negative ears on both sides are welded to the adapter 30 respectively to form a weld mark 221, wherein the positive and negative ears on both sides are respectively welded with two weld marks, the negative electrode weld mark area is welded with a negative electrode weld mark, and the positive electrode weld mark area is welded with a positive electrode weld mark. There are copper adapter poles on the copper adapter, and there are aluminum adapter poles on the aluminum adapter. After the battery cell 50 and the adapter 30 are welded, the copper adapter pole and the aluminum adapter pole pass through the through hole of the negative pole of the top cover 40 and the through hole of the positive pole of the top cover 40 respectively, and then the copper adapter pole and the negative pole of the top cover 40, and the aluminum adapter pole and the positive pole of the top cover 40 are sealed and welded together by laser. As shown Figure 4 After the top cover 40 and the battery cell 50 are welded and assembled together, the battery cell 50 is pressed into the aluminum shell, an interference fit is formed between the top cover 40 and the aluminum shell, and the top cover 40 and the aluminum shell are sealed and welded together using a laser.

[0051] Embodiment 2

[0052] The difference from the first embodiment is that the number of battery cells 50 is different.

[0053] like Figures 5 to 8 As shown, the secondary battery in this embodiment has a plurality of battery cells 50 , and the adapter 30 is simultaneously located in the installation area of ​​the plurality of battery cells 50 , and connects the tabs 20 of the plurality of battery cells 50 together.

[0054] like Figure 5 , Figure 6 As shown, taking two battery cells 50 as an example, after the pole tabs 20 of each battery cell 50 are layered along the middle pole tab 21 to form an installation area, the adapter plate 30 can be placed in the installation areas of the two battery cells 50 at the same time, so that the pole tabs 20 of the two battery cells 50 can be welded to the same adapter plate 30.

[0055] The adapter 30 in this embodiment includes a main body 31 and a plurality of contact portions 32 arranged at intervals, wherein the copper adapter can be provided with exhaust countersunk holes, each contact portion 32 is connected to the main body 31, and each contact portion 32 is respectively located in the installation area formed by the pole lugs 20 of the same polarity in different battery cells 50. Each contact portion 32 is welded to the pole lug 20 of a battery cell 50. Since the main body 31 of the adapter 30 is connected to the plurality of contact portions 32, the adapter 30 is connected to the plurality of battery cells 50, and the first pole 311 is located in the main body 31, so that the adapter 30 is connected to the second pole 41 of the top cover 40, thereby connecting the battery cell 50 to the top cover 40.

[0056] Optionally, instead of having only one pole ear 20 on each layer of the pole piece 10, at least two pole ears 20 may be provided as needed. In this way, the number of pole ears is increased, the current carrying capacity of the battery cell can be improved, the current path can be shortened, and the internal resistance of the battery cell can be reduced, thereby improving the charging efficiency of the battery cell.

[0057] Optionally, each contact portion 32 is welded to the pole ear 20 of a battery cell 50. In each battery cell 50, the first side pole ear bypasses one side of the contact portion 32 and is connected to the upper surface of the contact portion 32; the second side pole ear and the middle pole ear bypass the other side of the contact portion 32 and are connected to the upper surface of the contact portion 32.

[0058] Taking the battery having two cells 50 as an example, the specific assembly process is as follows:

[0059] like Figure 5 The two battery cells 50 shown are welded to the adapter plate 30, and the two battery cells 50 are matched together in the form of large surfaces sticking to large surfaces. For a battery containing two battery cells 50, each adapter plate is provided with two contact portions 32. First, the pole lug 20 of each battery cell 50 is separated from the middle pole lug 21 in the manner of Example 1 to form an installation space. Then, the first side pole lug of a battery cell 50 is passed around one side of a contact portion 32; the second side pole lug and the middle pole lug of the battery cell 50 are passed around the other side of the contact portion 32. Similarly, another battery cell 50 is assembled with another contact portion in the same manner. After all the pole lugs 20 have passed around the contact portion 32, the pole lugs 20 are kneaded and pressed on the upper surface of the contact portion 32, and finally welded. As shown Figure 6 As shown, after the two battery cells 50 are welded and assembled with the adapter 30, the first poles 311 of the aluminum adapter and the copper adapter respectively pass through the through holes of the positive and negative second poles of the top cover 40, and then the first pole 311 of the aluminum adapter and the second pole 41 of the positive pole of the top cover 40 are welded together using a laser, and then the first pole 311 of the copper adapter and the second pole 41 of the negative pole of the top cover 40 are welded together using a laser.

[0060] like Figure 7 As shown, the structure after three battery cells 50 are welded to the adapter sheet 30. The assembly method of this case is similar to that of two battery cells 50, and will not be described again.

[0061] like Figure 8 As shown, it is the structure after four battery cells 50 and the adapter sheet 30 are welded. The assembly method of this case is similar to that of two battery cells 50, and will not be described again.

[0062] It should be noted that, the multiple in the above embodiments refers to at least two.

[0063] From the above description, it can be seen that the above embodiments of the utility model achieve the following technical effects:

[0064] 1. Solved the problem of high internal resistance of the battery caused by high tab height.

[0065] 2. Reduce the height of the tab and the distance from the top surface of the battery cell to the top cover, thereby increasing the battery cell capacity per unit volume, reducing the risk of tab sinking, reducing the internal resistance of the battery cell, and reducing manufacturing costs.

[0066] 3. The setting of the middle pole ear makes it easy to bend the pole ear from the middle to both sides and separate them.

[0067] 4. Make the design of the number of internal cells of the battery simple, breaking the traditional design that the internal cells of the battery can only be 2JR or 4JR.

[0068] 5. Improve the current capacity of the battery cell, shorten the current path, and reduce the internal resistance of the battery cell, thereby improving the charging efficiency of the battery cell.

[0069] Obviously, the embodiments described above are only some embodiments of the utility model, not all embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0070] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0071] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0072] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A battery cell, characterized in that: include: A multilayer pole piece (10) formed by stacking along the thickness direction of the battery cell; A plurality of pole ears (20), each layer of the pole sheet (10) is provided with a pole ear (20) on one side, and at least part of the pole ears (20) are stacked in the thickness direction of the battery cell, and the direction in which the pole ears (20) protrude from the pole sheet (10) is the height direction of the battery cell; the direction perpendicular to the height direction of the battery cell and also perpendicular to the thickness direction of the battery cell is the width direction of the battery cell; the stacked pole ears (20) include side pole ears (22) located on both sides of the stacking direction and a middle pole ear (21) located between the side pole ears (22); in the width direction of the battery cell, the width of the middle pole ear (21) is greater than the width of the side pole ears (22).

2. The battery cell according to claim 1, characterized in that: Along the stacking direction of the pole lugs (20), the orthographic projection of the side pole lugs (22) on the surface of the middle pole lug (21) is located within the range of the middle pole lug (21).

3. The battery cell according to claim 2, characterized in that: Along the width direction of the battery cell, both ends of the middle pole lug (21) extend beyond the ends of the side pole lugs (22); and in the width direction of the battery cell, except for the middle pole lug (21), the remaining plurality of pole lugs (20) have the same width.

4. The battery cell according to claim 1, characterized in that: In the height direction of the battery cell, the height of the middle pole tab (21) is less than or equal to the height of the side pole tab (22).

5. The battery cell according to claim 1, characterized in that: All of the electrode tabs (20) include a positive electrode tab and a negative electrode tab, the positive electrode tabs are stacked on each other, the negative electrode tabs are stacked on each other, and the positive electrode tabs and the negative electrode tabs both include the intermediate electrode tab (21).

6. A secondary battery, characterized in that: include: The battery cell (50) according to any one of claims 1 to 5, wherein in the battery cell (50), a mounting area is formed between the middle pole ear (21) and the pole ear (20) adjacent to the middle pole ear (21), wherein the side pole ear (22) where the pole ear (20) forming the mounting area with the middle pole ear (21) is located is set as the first side pole ear, and the other side pole ear (22) is set as the second side pole ear; An adapter plate (30), the adapter plate (30) being located in the installation area; the first side pole ear bypassing one side edge of the adapter plate (30) and being connected to the upper surface of the adapter plate (30); the second side pole ear and the middle pole ear (21) bypassing the other side edge of the adapter plate (30) and being connected to the upper surface of the adapter plate (30).

7. The secondary battery according to claim 6, characterized in that: There are a plurality of battery cells (50), and the adapter sheet (30) is simultaneously located in the installation area of ​​the plurality of battery cells (50), and connects the tabs (20) of the same polarity in the plurality of battery cells (50) together.

8. The secondary battery according to claim 7, characterized in that: The adapter sheet (30) comprises a main body (31) and a plurality of contact portions (32) arranged at intervals, each of the contact portions (32) being connected to the main body (31), and each of the contact portions (32) being located in an installation area formed by pole tabs (20) of the same polarity in different battery cells (50), and being used for connecting to pole tabs (20) of the same polarity in different battery cells (50).

9. The secondary battery according to claim 8, characterized in that: Each of the contact portions (32) is connected to a pole lug (20) of the battery cell (50); in each of the battery cells (50), the first side pole lug bypasses one side edge of the contact portion (32) and is connected to an upper surface of the contact portion (32); and the second side pole lug and the middle pole lug bypass the other side edge of the contact portion (32) and are connected to an upper surface of the contact portion (32).

10. The secondary battery according to claim 6, characterized in that: The adapter plate (30) has a first pole (311), and the secondary battery further comprises a top cover (40), wherein the top cover (40) is arranged on the pole plate (10) of the battery cell (50), the pole lug (20) and the adapter plate (30) are located inside the top cover (40), and the top cover (40) has a second pole (41), and the first pole (311) is in contact and conduction with the second pole (41).

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