Pole lug structure of a wound lithium ion battery

Abstract

The utility model discloses a kind of tab structures of winding type lithium ion battery, it is related to battery technical field, including positive plate, negative plate and diaphragm, the positive plate and the negative plate all include several independent circles, several the independent circle head is connected, the independent circle of the positive plate is equipped with positive tab, the independent circle of the negative plate is equipped with negative tab, at least one the independent circle on inside is equipped with two tabs, at least one the independent circle on outside is equipped with one tab, using full tab design, limit tab compaction density and limit hot-pressing pressure can be compatible, ensure that battery performance is not affected.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a tab structure for a wound lithium-ion battery. Background Technology

[0002] Existing technical solutions primarily focus on addressing the alignment issue of the electrode tabs in the battery core, but do not address solutions related to core manufacturing. As the compaction density of current electrode designs gradually increases, the bending structures on both sides of the electrode are prone to breakage due to the bending angle and the inherent brittleness of the electrode itself. Especially considering that the hot-pressing pressure used in current large-capacity battery core designs generally exceeds 10 tons, this significantly increases the risk of breakage at the innermost electrode corner (R-angle). Electrode breakage due to hot pressing will have a substantial impact on the battery cell, reducing its capacity. Utility Model Content

[0003] Purpose of the utility model: The technical problem to be solved by this utility model is to provide a tab structure for a wound lithium-ion battery, which solves the problem that the bending position of the existing electrode is prone to breakage, thus having a significant impact on the cell capacity.

[0004] Technical solution

[0005] To solve the above problems, the technical solution provided by this utility model is as follows:

[0006] A tab structure for a wound lithium-ion battery includes a positive electrode sheet, a negative electrode sheet, and a separator. Both the positive electrode sheet and the negative electrode sheet include several independent coils connected end to end. The independent coils of the positive electrode sheet are provided with positive electrode tabs, and the independent coils of the negative electrode sheet are provided with negative electrode tabs. At least one independent coil located on the inner side is provided with two tabs, and at least one independent coil located on the outer side is provided with one tab.

[0007] Furthermore, the two tabs on the inner independent coil are respectively located on both sides of the length direction of the independent coil.

[0008] Furthermore, a plurality of the positive electrode tabs are located on the same straight line and are connected to each other, and a plurality of the negative electrode tabs are located on the same straight line and are connected to each other.

[0009] Furthermore, the positive electrode tab and the negative electrode tab are located on both sides of the width direction of the independent coil.

[0010] Furthermore, the positive electrode and the negative electrode are separated into independent electrodes according to the positive electrode tab and the negative electrode tab.

[0011] Furthermore, the independent loop is a ring structure with the inner and outer ends forming a ring shape.

[0012] Furthermore, the initial and final points on the same independent loop lie on the same straight line perpendicular to the spiral multilayer structure, with the final point located outside the initial point.

[0013] Furthermore, the positive electrode, the negative electrode, and the separator are stacked and laid out in a multilayer structure according to the separator, the positive electrode, the separator, the negative electrode, and the separator.

[0014] Furthermore, the multi-layer structure is wound to form a battery cell.

[0015] Beneficial effects

[0016] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0017] The technical solution provided by this utility model adopts a near-full tab design, which is compatible with the maximum electrode compaction density and maximum hot-pressing pressure, ensuring that the cell performance is not affected. Similarly, in the ultrasonic welding process, process quality abnormalities are prevented in advance at the design stage, improving the yield of cell products and effectively avoiding capacity loss caused by breakage due to excessive stress at the innermost folded electrode R-corner. It also provides more fault tolerance for the ultrasonic welding process, effectively reducing the quality risk caused by tearing of the upper electrode tab during ultrasonic welding, ensuring the current carrying capacity of the core, and increasing the safety and stability of the cell. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the electrode tab layout in Embodiment 1 of this utility model;

[0019] Figure 2 This is a schematic diagram of the inner bipolar tab layout of Embodiment 1 of this utility model;

[0020] Figure 3 This is a schematic diagram of the outer monopole layout of Embodiment 1 of this utility model;

[0021] Figure 4 This is an isometric view of the structure of Embodiment 1 of this utility model;

[0022] Figure 5 for Figure 4 An enlarged view of point A in the middle diagram.

[0023] 1. Positive electrode plate; 2. Negative electrode plate; 3. Separator; 11. Positive electrode tab; 21. Negative electrode tab; Detailed Implementation

[0024] To make the technical solution of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1

[0026] Combined with appendix Figure 1-5 A spiral-wound lithium-ion battery electrode structure is formed by spiral-wound a positive electrode 1, a negative electrode 2, and a separator 3. The separator 3 is used to separate adjacent positive electrode 1 and negative electrode 2 and to protect the positive and negative electrode sheets. The positive electrode 1, negative electrode 2, and separator 3 are stacked and laid in the manner of separator 3, positive electrode 1, separator 3, negative electrode 2, separator 3 to form an overlapping multilayer structure. Then, the multilayer structure is spiral-wound to form a spiral-wound cell structure. The spiral-wound electrode sheet and negative electrode 2 are provided with a number of positive electrode tabs 11 and negative electrode tabs 21. The positive and negative terminals formed by the positive electrode tabs 11 and negative electrode tabs 21 respectively enable the spiral-wound cell to have the ability to supply power and store electricity.

[0027] The multi-layer stacked structure forms a spiral multi-layer structure with outward spiral expansion after winding. Taking any point on the positive electrode 1 or negative electrode 2 as the initial point, it moves along the winding path of the positive electrode 1 or negative electrode 2. The point on the positive electrode 1 or negative electrode 2 located at the same position outside the initial point is taken as the ending point. The positive electrode 1 and negative electrode 2 between the initial point and the ending point are considered as a separate turn, i.e., an independent turn.

[0028] The initial and final points on the same independent loop lie on the same straight line perpendicular to the spiral multilayer structure, with the final point located outside the initial point.

[0029] Because the wound battery cell is hot-pressed to form a flat structure, the battery cell will be bent on both sides in the width direction due to hot pressing. At the same time, the initial point and the end point on the same independent loop are located on the same straight line perpendicular to the length direction of the battery cell, and the end point is located on the outermost positive electrode 1 or negative electrode 2 that is closest to the initial point on the positive electrode 1 or negative electrode 2.

[0030] The electrode between the initial point on the positive electrode 1 and the ending point on the positive electrode 1 located outside the initial point forms an independent loop. The initial point on the negative electrode 2 and the ending point on the negative electrode 2 located outside the initial point form an independent loop. The corresponding initial points and ending points of the positive electrode 1 and the negative electrode 2 are located on the same straight line. The independent loop is a ring structure with the beginning and end points on both sides.

[0031] After being wound, the positive electrode 1 and the negative electrode 2 form multiple independent loops connected end to end. The independent loops on the positive electrode 1 and the negative electrode 2 are stacked and intertwined to form a battery cell.

[0032] The spiral multi-layer structure of the wound battery cell starts from the inner end of the positive electrode 1 and the negative electrode 2 in the spiral multi-layer structure. From the starting point, it is distinguished outward according to the independent loops. Thus, it can be seen that the core formed by the winding of the positive electrode 1 and the negative electrode 2 is formed by connecting the ends of multiple independent loops of the positive electrode 1 and the negative electrode 2.

[0033] The battery cell has electrode tabs, which are divided into positive electrode tabs 11 and negative electrode tabs 21. Several positive electrode tabs 11 are integrally formed on the positive electrode plate 1, and several negative electrode tabs 21 are formed on the negative electrode plate 2. Inside a single battery cell, all the positive electrode tabs 11 are electrically connected to each other to form a positive terminal, and all the negative electrode tabs 21 are electrically connected to each other to form a negative terminal.

[0034] At the same time, each positive and negative tab will divide the positive and negative electrode plate 2 into independent electrode plates. According to the number of tabs on each independent coil, the independent coil is divided into independent electrode plates of different lengths. Then, several independent positive electrode plates are electrically connected to each other and several independent negative electrode plates are electrically connected to each other.

[0035] When setting the positive electrode 1 independent coil and the negative electrode 2 independent coil, the positive electrode tab 11 and the negative electrode tab 21 are set in a corresponding staggered manner. Each independent coil of positive electrode 1 is set with at least one positive electrode tab 11, and each independent coil of negative electrode 2 is set with at least one negative electrode tab 21.

[0036] On several independent coils of positive electrode 1 and negative electrode 2 located inside the spiral multilayer structure of the battery cell, two positive electrode tabs 11 and two negative electrode tabs 21 are respectively provided. The independent coils with two positive and negative electrode tabs 21 are arranged outward from the innermost independent coil of the spiral multilayer structure of the battery cell.

[0037] Preferably, two tabs are provided on the independent ring of the innermost three-layer positive and negative electrode sheet 2. Since the innermost three layers are prone to breakage at the bending parts on both sides during the hot pressing of the cell, designing two tabs can reduce the impact of electrode sheet breakage on the cell capacity.

[0038] Because the length and width of the battery cell are unequal after winding, the two positive and negative electrode tabs 21 on the independent coil are respectively set on both sides of the length direction of each independent coil. That is, on one independent coil of the positive electrode plate 1, two positive electrode tabs 11 are integrally set on both sides of the length direction of the positive independent coil. On one independent coil of the negative electrode plate 2, two negative electrode tabs 21 are integrally set on both sides of the length direction of the negative independent coil.

[0039] In the subsequent ultrasonic welding process of the electrode tabs, the first three layers of electrode tabs are prone to cracking, which will weaken the current carrying capacity of the cell and even cause capacity loss. The multi-tab design on the inner side will effectively avoid this situation and improve the manufacturing quality of the cell from the electrode and core design.

[0040] All the positive electrode tabs 11 and negative electrode tabs 21 in the battery cell are staggered. The positive electrode tabs 11 and negative electrode tabs 21 are respectively located on both sides of the width direction of the battery cell. That is, all the positive electrode tabs 11 are located on the same straight line and all the negative electrode tabs 21 are located on the same straight line, which facilitates the electrical connection of all the positive electrode tabs 11 and all the negative electrode tabs 21 to form terminals.

[0041] A positive and negative electrode tab 21 is provided on the independent positive and negative electrode rings at the outer end of the spiral multilayer structure of the battery cell, that is, a positive electrode tab 11 is integrally provided on the outer positive electrode ring, and a negative electrode tab 21 is integrally provided on the outer negative electrode ring.

[0042] In the spiral multilayer structure of the battery cell, the arc-shaped part used for winding is set on both sides of the width direction, that is, the arc-shaped part used to form the winding is at both ends of the width direction of the independent coil, and the electrode tabs on the independent coil with two tabs are respectively set on both sides of the width direction. Since the positive and negative electrode tabs 21 are set on both sides of the width of the independent coil, the electrode tabs are located inside the arc-shaped part on the independent coil.

[0043] The independent coil with two tabs is divided into two independent energy storage sections. The dividing point is located inside the arc-shaped section, also known as the inner folded R-angle. Since the battery cell needs to be hot-pressed after winding, excessive stress at the inner folded R-angle during the hot-pressing process can cause breakage. The inner independent coil has a larger inner folded R-angle, making it more prone to breakage. After dividing the inner independent coil into two independent parts, the arc-shaped section breaks when pressed by hand, and its breakage location is close to the dividing point. The capacity of the two energy storage sections on the independent coil is less affected. Therefore, the arc-shaped section (inner folded R-angle) does not affect the normal capacity performance of the entire core.

[0044] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A tab structure for a wound lithium-ion battery, characterized in that, It includes a positive electrode plate, a negative electrode plate, and a separator. Both the positive electrode plate and the negative electrode plate include several independent coils connected end to end. The independent coils of the positive electrode plate are provided with positive electrode tabs, and the independent coils of the negative electrode plate are provided with negative electrode tabs. At least one independent coil located on the inner side is provided with two tabs, and at least one independent coil located on the outer side is provided with one tab.

2. The tab structure of a wound lithium-ion battery according to claim 1, characterized in that, The two tabs on the inner side of the independent coil are respectively located on both sides of the length direction of the independent coil.

3. The tab structure of a wound lithium-ion battery according to claim 1, characterized in that, Several positive electrode tabs are located on the same straight line and are connected to each other; several negative electrode tabs are located on the same straight line and are connected to each other.

4. The tab structure of a wound lithium-ion battery according to claim 3, characterized in that, The positive electrode tab and the negative electrode tab are located on both sides of the width direction of the independent coil, respectively.

5. The tab structure of a wound lithium-ion battery according to claim 1, characterized in that, The positive electrode and the negative electrode are separated into independent electrode plates according to the positive electrode tab and the negative electrode tab.

6. The tab structure of a wound lithium-ion battery according to claim 1, characterized in that, The independent loop is a ring structure with the inner and outer ends forming a ring.

7. The tab structure of a wound lithium-ion battery according to claim 1, characterized in that, The initial and final points on the same independent loop lie on the same straight line perpendicular to the spiral multilayer structure, with the final point located outside the initial point.

8. The tab structure of a wound lithium-ion battery according to claim 1, characterized in that, The positive electrode, the negative electrode, and the separator are stacked and laid out in a multi-layer structure.

9. The tab structure of a wound lithium-ion battery according to claim 8, characterized in that, The multi-layer structure is wound to form the battery cell.

Images