Stacked cells and secondary batteries

Abstract

This utility model discloses a stacked battery cell, including a cell body, which includes positive and negative electrode sheets stacked alternately, with a separator between the positive and negative electrode sheets. Each positive electrode sheet has a positive electrode tab, and each positive electrode tab forms at least two sets of positive electrode tab groups. These sets of positive electrode tabs are spaced apart along the length of the positive electrode sheet. The free ends of the positive electrode tab groups are welded to form welding ends, and the spacing between the welding ends of each positive electrode tab group in the stacking direction does not exceed 1 mm. The negative electrode sheet has a negative electrode tab. This stacked battery cell divides the positive electrode tabs into multiple positive electrode tab groups, significantly reducing the number of positive electrode tabs that need to be welded within the same positive electrode tab group, thereby reducing the risk of incomplete soldering during the welding process. Furthermore, the thickness and position of each positive electrode tab group in the stacking direction of the cell body are basically the same; therefore, each positive electrode tab group can be welded in a single welding step, improving welding quality and consistency.

Description

Technical Field

[0001] This utility model relates to the field of secondary battery technology, specifically a stacked cell and a secondary battery. Background Technology

[0002] With the rapid development of new energy vehicles and energy storage power stations, lithium batteries have become the mainstream energy storage device due to their advantages such as high energy density and long cycle life. Cost reduction is a crucial theme throughout the development of lithium batteries. Currently, large-scale energy storage batteries (such as 280Ah and larger capacities) are becoming the next key development direction due to their advantages in system integration and cost per kilowatt-hour.

[0003] Compared to winding, stacking technology exhibits significant advantages in large prismatic batteries, such as higher space utilization, more uniform stress distribution, lower electrode bending stress, better rate performance, and longer cycle life. Therefore, leading battery manufacturers widely adopt stacking technology in the field of large-scale energy storage batteries.

[0004] The core of the lamination process is to alternately stack a large number of positive and negative electrode sheets with a separator to form the battery cell body. However, as battery capacity increases, the number of electrode layers required increases significantly, leading to problems such as poor soldering during subsequent ultrasonic welding of the electrode tabs. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a stacked battery cell and a secondary battery. This stacked battery cell divides the positive electrode tabs into multiple positive electrode tab groups, significantly reducing the number of positive electrode tabs that need to be welded within the same positive electrode tab group, thereby reducing the risk of incomplete welds during the welding process. Simultaneously, the thickness and position of each positive electrode tab group in the stacking direction of the battery cell body are basically the same. Therefore, when welding each positive electrode tab group, only one welding step is required to complete the welding of each group, improving welding quality and consistency.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is: a stacked battery cell, comprising a battery cell body, wherein the battery cell body comprises positive electrode plates and negative electrode plates stacked in an alternating sequence, and a separator is provided between the positive and negative electrode plates, characterized in that the positive electrode plate is provided with a positive electrode tab, each positive electrode tab forming at least two sets of positive electrode tab groups, each set of positive electrode tabs being spaced apart from each other in the length direction of the positive electrode plate, the free ends of the positive electrode tab groups being welded to form welding ends, and the spacing between the welding ends of each set of positive electrode tabs in the stacking direction of the battery cell not exceeding 1 mm; The negative electrode plate is provided with a negative electrode tab.

[0007] By employing the aforementioned technical solution, the positive electrode tabs are divided into multiple positive electrode tab groups, significantly reducing the number of positive electrode tabs that need to be welded within the same positive electrode tab group, thereby lowering the risk of incomplete soldering during the welding process. Furthermore, the thickness and position of each positive electrode tab group in the cell body stacking direction are essentially the same; therefore, each positive electrode tab group can be welded in a single welding step, improving welding quality and consistency.

[0008] Furthermore, the tabs in each positive electrode tab group are alternately arranged on the positive electrode sheet along the stacking direction.

[0009] Furthermore, it also includes a positive electrode connector, which is connected to the welding end of each positive electrode tab assembly. The positive electrode tab assemblies are connected into a whole by the positive electrode connector to form the positive electrode lead-out terminal for connecting the battery terminal.

[0010] Furthermore, each negative electrode tab forms at least two sets of negative electrode tab groups, and each negative electrode tab group is spaced apart from each other in the length direction of the negative electrode sheet. The free ends of the negative electrode tab groups are welded to form welding ends, and the spacing between the welding ends of each negative electrode tab group in the cell stacking direction does not exceed 1 mm.

[0011] By employing the aforementioned technical solution, the negative electrode tabs are divided into multiple negative electrode tab groups, significantly reducing the number of negative electrode tabs that need to be welded within the same negative electrode tab group, thereby lowering the risk of incomplete soldering during the welding process. Furthermore, the thickness and position of each negative electrode tab group in the cell body lamination direction are essentially the same; therefore, each negative electrode tab group can be welded in a single welding step, improving welding quality and consistency.

[0012] Furthermore, it also includes a negative electrode connector, which is connected to the welding end of each negative electrode tab assembly. The negative electrode tab assemblies are connected into a whole by the negative electrode connector to form the negative electrode lead-out terminal for connecting the battery terminal.

[0013] Furthermore, within the same positive electrode tab group, the length of the positive electrode tab increases from the middle to both sides; Within the same negative electrode tab group, the length of the negative electrode tab increases from the middle to both sides.

[0014] Within the same tab group, during welding, the tabs on both sides need to be brought closer to the center. Through the design of increasing length, the length of each tab in the same tab group is made consistent after welding.

[0015] Furthermore, the positive and negative electrode tabs are located on the same side of the cell body. This arrangement facilitates the subsequent installation of the cell body into the battery casing and the connection of the tabs and terminals.

[0016] Furthermore, the spacing between each positive electrode tab group in the length direction of the positive electrode sheet shall not exceed 1 mm; Each negative electrode tab group is spaced no more than 1 mm apart along the length of the negative electrode sheet.

[0017] The interval of no more than 1mm facilitates the simultaneous welding of each positive electrode tab group or each negative electrode tab group in subsequent welding processes.

[0018] Furthermore, the positive electrode sheet and the positive electrode tab are integrally formed; The negative electrode sheet and the negative electrode tab are integrally formed.

[0019] A secondary battery comprising the aforementioned stacked cells.

[0020] Based on the above technical solution, the beneficial effects of this utility model are as follows: The laminated cell disclosed in this application divides the positive electrode tab into multiple positive electrode tab groups, which greatly reduces the number of positive electrode tabs that need to be soldered in the same positive electrode tab group, thereby reducing the risk of cold solder joints during the soldering process. In this application, the thickness of each positive electrode tab group and its position in the stacking direction of the cell body are basically the same. Therefore, when welding each positive electrode tab group, only one welding step is needed to complete the welding of each positive electrode tab group, thereby improving the welding quality and consistency.

[0021] To make the above and other objects, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the overall structure of the stacked battery cell in this embodiment of the present invention; Figure 2 This is a partial schematic diagram of the positive electrode sheet in an embodiment of this utility model; Figure 3 This is a schematic diagram of another stacked battery cell in an embodiment of this utility model; Figure 4 This is a side view of a stacked battery cell after the tabs have been welded together.

[0024] The reference numerals in the above figures are as follows: 1. Battery cell; 11. Positive electrode plate; 12. Negative electrode plate; 13. Separator; 2. First positive electrode tab group; 21. First positive electrode tab; 3. Second positive electrode tab group; 31. Second positive electrode tab; 4. First negative electrode tab group; 5. Second negative electrode tab group. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] It should be noted that in the description of this utility model, the terms "first," "second," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0027] Example: This example discloses a stacked battery cell, including a battery cell body 1. The battery cell body 1 includes positive electrode plates 11 and negative electrode plates 12 stacked in an alternating order. A separator 13 is provided between the positive electrode plates 11 and negative electrode plates 12. The positive electrode plates 11 are provided with positive electrode tabs. Each positive electrode tab forms at least two sets of positive electrode tab groups. Each set of positive electrode tabs is spaced apart from each other in the length direction of the positive electrode plates 11. The free ends of the positive electrode tab groups are welded to form welding ends. The spacing between the welding ends of each set of positive electrode tabs in the stacking direction of the battery cell does not exceed 1 mm. Each of the negative electrode plates 12 is provided with a negative electrode tab, and the various negative electrode tabs form a negative electrode tab group.

[0028] The welding end is formed by welding the welding points of each positive electrode tab.

[0029] By employing the aforementioned technical solution, the positive electrode tabs are divided into multiple positive electrode tab groups, significantly reducing the number of positive electrode tabs that need to be welded within the same positive electrode tab group, thereby lowering the risk of incomplete soldering during the welding process. Furthermore, the thickness and position of each positive electrode tab group in the lamination direction of the cell body are essentially the same. Therefore, when welding each positive electrode tab group, only one welding step is required to complete the welding of each positive electrode tab group, thus improving welding quality and consistency.

[0030] In some feasible embodiments, the battery cell body 1 includes 400 layers each of a positive electrode 11, a separator 13, and a negative electrode 12. Two sets of positive electrode tabs are provided, namely a first positive electrode tab group 2 and a second positive electrode tab group 3, wherein the tab in the first positive electrode tab group 2 is a first positive electrode tab 21, and the tab in the second positive electrode tab group 3 is a second positive electrode tab 31. Figure 1 , 2 As shown, the first positive electrode tab 21 and the second positive electrode tab 31 are alternately arranged on the positive electrode sheet 11 along the stacking direction. In the length direction of the positive electrode sheet 11, the first positive electrode tab 21 and the second positive electrode tab 31 on two adjacent positive electrode sheets 11 are 1 mm apart.

[0031] It should be noted that, with Figure 2 For example, the length direction of the positive electrode 11 is oriented left and right.

[0032] In this configuration, along the length of the cell body 1, each of the first positive electrode tabs 21 is located at the same position on the cell body 1, and all the first positive electrode tabs 21 form a first positive electrode tab group 2; each of the second positive electrode tabs 31 is located at the same position on the cell body 1, and all the second positive electrode tabs 31 form a second positive electrode tab group 3. The first positive electrode tab group 2 and the second positive electrode tab group 3 are spaced 1 mm apart along the length of the cell body 1.

[0033] Optionally, along the length of the positive electrode 11, the two types of positive electrode tabs on adjacent positive electrode 11 can be spaced no more than 1 mm apart. This 1 mm spacing facilitates the simultaneous welding of each positive electrode tab group or each negative electrode tab group in subsequent welding processes. like Figure 1 As shown, the thickness of the first positive electrode tab group 2 and the second positive electrode tab group 3, as well as their positions in the lamination direction of the cell body 1, are basically the same. Therefore, when welding the first positive electrode tab group 2 and the second positive electrode tab group 3, only one welding step is needed to complete the welding, thereby improving the welding quality and consistency. After welding, the welding ends of each positive electrode tab group are in the same position in the lamination direction of the cell body 1, that is, the welding ends of each positive electrode tab group are on the same horizontal line.

[0034] In some feasible embodiments, three, four, or more sets of positive electrode tabs can be provided, and the positive electrode tabs in each positive electrode tab set are alternately arranged on the positive electrode sheet 11 along the stacking direction. In the length direction of the positive electrode sheet 11, the two types of positive electrode tabs on adjacent positive electrode sheets 11 are spaced no more than 1 mm apart. The more types of positive electrode tabs provided, the thinner the thickness of each positive electrode tab set, which is more beneficial for subsequent welding processes. It should be noted that because there are intervals between the various positive electrode tabs, the more types of positive electrode tabs there are, the more length of the positive electrode sheet 11 it occupies. Therefore, when setting the positive electrode tabs, it is necessary to ensure that the positive electrode tabs do not come into contact with the negative electrode tabs.

[0035] The welding ends of each positive electrode tab assembly are respectively connected to the positive electrode connector, and the positive electrode tab assemblies are connected into a whole through the positive electrode connector to form the positive electrode lead-out terminal for connecting to the battery terminal. The positive electrode connector can be a metal busbar or a connecting piece. During connection, the welding ends of each positive electrode tab assembly are connected to the positive electrode connector by riveting, screwing, or secondary welding.

[0036] Each of the negative electrode plates 12 is provided with a negative electrode tab, and the negative electrode tabs together form a negative electrode tab group.

[0037] In some feasible embodiments, each negative electrode tab forms at least two sets of negative electrode tab groups, each negative electrode tab group is spaced apart from each other in the length direction of the negative electrode sheet 12, the free ends of the negative electrode tab groups are welded to form welding ends, and the spacing between the welding ends of each negative electrode tab group in the cell stacking direction does not exceed 1mm.

[0038] In some feasible embodiments, two sets of negative electrode tabs are provided, namely a first negative electrode tab group 4 and a second negative electrode tab group 5, wherein the tabs in the first negative electrode tab group 4 are the first negative electrode tabs, and the tabs in the second negative electrode tab group 5 are the second negative electrode tabs. Combined with Figure 1 , 2 As shown, the first negative electrode tab and the second negative electrode tab are alternately arranged on the negative electrode sheet 12 along the stacking direction. In the length direction of the negative electrode sheet 12, the first negative electrode tab and the second negative electrode tab on two adjacent negative electrode sheets 12 are 1 mm apart.

[0039] like Figure 3 As shown, along the length of the cell body 1, each of the first negative electrode tabs is located at the same position on the cell body 1, and all the first negative electrode tabs form a first negative electrode tab group 4; each of the second negative electrode tabs is located at the same position on the cell body 1, and all the second negative electrode tabs form a second negative electrode tab group 5. The first negative electrode tab group 4 and the second negative electrode tab group 5 are 1 mm apart along the length of the cell body 1.

[0040] In some feasible embodiments, similar to the positive electrode tab, three, four or more negative electrode tab groups can be set, and the negative electrode tabs in each negative electrode tab group are alternately arranged on the negative electrode sheet 12 along the stacking direction. In the length direction of the negative electrode sheet 12, the two types of negative electrode tabs on two adjacent negative electrode sheets 12 are not more than 1 mm apart.

[0041] Each negative electrode tab group is connected into a whole by a negative electrode connector to form the negative electrode lead-out terminal for connecting to the battery terminal. The negative electrode connector can be a metal busbar or a connecting piece. During connection, the welded ends of each negative electrode tab group are connected to the negative electrode connector by riveting, screwing, or secondary welding.

[0042] Within the same positive electrode tab group, the length of the positive electrode tab increases from the center outwards; similarly, within the same negative electrode tab group, the length of the negative electrode tab increases from the center outwards. During soldering within the same tab group, the tabs on both sides must be brought closer to the center. This increasing length design ensures that all tabs within the same tab group are of uniform length after soldering. The soldered laminated battery cell is as follows: Figure 4 As shown.

[0043] The positive and negative electrode tabs are located on the same side of the cell body. This arrangement facilitates the subsequent installation of the cell body 1 into the battery casing and the connection of the tabs and terminals.

[0044] The positive electrode sheet and positive electrode tab are integrally formed; the negative electrode sheet and negative electrode tab are integrally formed. That is, electrodes with various tabs are directly die-cut during the electrode sheet cutting process.

[0045] This application also discloses a secondary battery comprising the aforementioned stacked cells.

[0046] This utility model uses specific embodiments to illustrate the principle and implementation of the utility model. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​the utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the utility model. Therefore, the content of this specification should not be construed as a limitation of the utility model.

Claims

1. A stacked battery cell, comprising a cell body, the cell body including positive electrode plates and negative electrode plates stacked in an alternating sequence, with a separator provided between the positive and negative electrode plates, characterized in that, The positive electrode sheet is provided with positive electrode tabs, and each positive electrode tab forms at least two sets of positive electrode tab groups. Each set of positive electrode tabs is spaced apart from each other in the length direction of the positive electrode sheet. The free ends of the positive electrode tab groups are welded to form welding ends. The spacing between the welding ends of each set of positive electrode tabs in the cell stacking direction does not exceed 1mm. The negative electrode plate is provided with a negative electrode tab.

2. The laminated cell as described in claim 1, characterized in that, The tabs in each positive electrode tab group are alternately arranged on the positive electrode sheet along the stacking direction.

3. The laminated cell as described in claim 1, characterized in that, It also includes a positive electrode connector, which is connected to the welding end of each positive electrode tab assembly.

4. The laminated cell as described in claim 1, characterized in that, Each negative electrode tab forms at least two negative electrode tab groups, and each negative electrode tab group is spaced apart from each other in the length direction of the negative electrode sheet. The free ends of the negative electrode tab groups are welded to form welding ends, and the spacing between the welding ends of each negative electrode tab group in the cell stacking direction does not exceed 1 mm.

5. The laminated cell as described in claim 4, characterized in that, It also includes a negative electrode connector, which is connected to the welding end of each negative electrode lug assembly.

6. The laminated cell as described in claim 4, characterized in that, Within the same positive electrode tab group, the length of the positive electrode tab increases from the middle to both sides; Within the same negative electrode tab group, the length of the negative electrode tab increases from the middle to both sides.

7. The laminated cell as described in claim 4, characterized in that, The positive and negative electrodes are located on the same side of the battery cell body.

8. The laminated cell as described in claim 4, characterized in that, Each positive electrode tab group is spaced no more than 1 mm apart along the length of the positive electrode plate; Each negative electrode tab group is spaced no more than 1 mm apart along the length of the negative electrode sheet.

9. The laminated cell as described in claim 1 or 4, characterized in that, The positive electrode plate and the positive electrode tab are integrally formed; The negative electrode sheet and the negative electrode tab are integrally formed.

10. A secondary battery, characterized in that, Includes the stacked battery cell as described in any one of claims 1-8.

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