Magnesium battery tab

Abstract

The application relates to the technical field of magnesium secondary battery cells, and particularly discloses a magnesium battery tab; the tab comprises at least two main body parts, a buffer part is arranged between the two adjacent main body parts, the thickness of the buffer part is smaller than that of the main body part, and the difference between the thicknesses of the buffer part and the main body part is D n , D / 10<=D n <=D / 4. The application solves the problem of high welding difficulty of multilayer tab in a magnesium secondary battery.

Description

Technical Field

[0001] This invention relates to the field of magnesium secondary battery cell technology, specifically to a magnesium battery tab. Background Technology

[0002] Battery technology, as a crucial component of modern energy storage technology, is widely used in portable electronic devices, electric vehicles, and energy storage. Among these, magnesium secondary batteries are particularly valuable due to their high theoretical energy density (magnesium ions carry two electrons, with a theoretical volumetric capacity of 3383 mAh / cm³). 3 Magnesium, with its abundant resources and excellent safety performance, has become a research hotspot in the field and is considered one of the most promising battery systems to replace lithium batteries. Magnesium secondary batteries are recyclable batteries that use metallic magnesium as the negative electrode. A magnesium secondary battery mainly includes a magnesium negative electrode, an electrolyte, and a magnesium intercalating element. 2+ The positive electrode material. The electrode sheet and electrode tab are the positive and negative electrodes in the battery, used to lead the positive and negative electrodes out from the inside of the cell and ensure that the current can be transferred from the inside to the external circuit, so as to realize the charging and discharging behavior of the battery.

[0003] Electrodes and tabs are usually fixed by welding. In order to improve the single-cell capacity and energy density of magnesium secondary batteries, multi-layer stacking process is usually adopted. At the same time, since the Mg foil material of the negative electrode of magnesium-ion batteries is currently quite thick, the electrode tabs and outer tabs need to be welded multiple times to form multiple welding points during multi-layer welding. Multiple welding can easily cause tearing of the tabs, resulting in poor welding effect and high scrap rate, which deteriorates the cell performance and increases manufacturing cost. Summary of the Invention

[0004] The present invention aims to provide a magnesium battery tab to solve the problem of high difficulty in welding multi-layered electrodes in magnesium batteries.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a magnesium battery tab, comprising at least two main body portions, with a buffer portion provided between two adjacent main body portions, wherein the thickness of the buffer portion is less than the thickness of the main body portion, and the difference in thickness between the buffer portion and the main body portion is D. n D / 10≤D n ≤D / 4.

[0006] The beneficial effects of this plan are:

[0007] 1. In this solution, when welding the tabs and the electrode sheet, the welding point between the electrode sheet and the tab is located on the main body. Since the buffer part acts as a separator between two adjacent main bodies, there is a large distance between the two adjacent main bodies. Therefore, the adjacent welding points will not be pulled and damaged, and the welding strength is also greater. Thus, more welding can be performed, reducing the welding difficulty.

[0008] 2. The thickness of the buffer section is smaller than that of the main body, making the buffer section more flexible and less prone to breakage of the tabs during welding. Although multi-layered electrodes also exist in current conventional lithium battery systems, the electrodes in lithium batteries are composed of multiple copper foils with a thickness of 5-10µm, and the tabs are nickel / copper plated nickel tabs. The thickness of the copper foil is small, and even if multiple layers of copper foil are used to form multi-layered electrodes, the thickness of these electrodes is still relatively small.

[0009] However, the tabs in this invention are used in magnesium secondary batteries. Magnesium-ion battery systems use multiple magnesium foils or magnesium alloy foils with a thickness ≥50µm to form multilayer electrodes. The thickness of these electrodes is much greater than that of lithium battery systems. This excessive thickness makes the tabs in magnesium secondary batteries prone to tearing during repeated welding. Conventional designs reduce the number of welding layers to prevent the tabs from breaking under stress and ensure welding quality, but this limits the cell's capacity and energy density.

[0010] However, the buffer part in this invention forms a weak area that is easily deformable by reducing its thickness, providing a certain deformation space. When multiple welding is performed, the stress between different welding points may cause the electrode tabs to be torn. At this time, the buffer part deforms first to eliminate the interaction force between the welding points and reduce the risk of welding point failure.

[0011] Furthermore, the centerline of the buffer section coincides with the centerline of the main body section.

[0012] The beneficial effects of this solution are as follows: Due to the large number of electrode plates, the inventor has developed a welding process in which electrode plates are alternately welded on both sides of the electrode plate. The buffer part in this solution is located in the middle of the main body. When welding the electrode plates located on both sides of the electrode plate, the electrode plates can bend and deform without breaking.

[0013] Furthermore, a ramp is provided between the buffer section and the main body section, and the angle between the ramp and the surface of the buffer section is an obtuse angle.

[0014] The beneficial effects of this solution are: it can avoid stress concentration caused by excessively sharp angles, which would reduce the strength of the tab itself.

[0015] Furthermore, the angle between the slope and the buffer section is α, where 120°≤α≤150°.

[0016] The beneficial effect of this solution is that the slope is stress-dispersed when subjected to force, so that the contact point between the slope and the buffer section will not be damaged due to stress concentration.

[0017] Furthermore, the length of any one of the main body parts is L, where 8mm ≤ L ≤ 15mm.

[0018] The beneficial effects of this solution are: while ensuring good welding results, the main body of this solution also avoids the adverse effects of excessive cell length on cell energy density.

[0019] Furthermore, the distance between adjacent main body parts is L0, where 5mm ≤ L0 ≤ (1 / n)*(L1 + L2 + ... + L n ).

[0020] The beneficial effects of this scheme are as follows: where n represents the number of main body parts, L1, L2, and Ln are the lengths of the first main body part, the second main body part, and the nth main body part, respectively, and "L1 + L2 + ... + Ln" represents the length of the nth main body part. n "" represents the sum of the lengths of all main body sections. In this scheme, the length between adjacent main body sections is limited, thereby limiting the length of the buffer section. This ensures that the buffer section provides a good buffering effect while also preventing the excessive length of the battery cell from adversely affecting the energy density.

[0021] Furthermore, reinforcing ribs are fixed on the buffer section.

[0022] Furthermore, the reinforcing ribs include ring-shaped ones.

[0023] Furthermore, the reinforcing ribs are strip-shaped.

[0024] Furthermore, the reinforcing ribs are round or wavy.

[0025] The beneficial effects of this solution are as follows: the reinforcing ribs can increase the strength of the buffer part, and while maintaining the good flexibility of the buffer part, further prevent the buffer part from easily breaking due to the thinning of the thickness. While ensuring that the electrode tab has sufficient mechanical strength, it can also greatly reduce the risk of welding failure and improve the welding qualification rate. Attached Figure Description

[0026] Figure 1 This is a front view of Embodiment 1 of the present invention;

[0027] Figure 2 for Figure 1 The left view;

[0028] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0029] Figure 4 for Figure 1 Enlarged view of point B in the middle;

[0030] Figure 5 This is a schematic diagram of the welding of the electrode tab and the electrode sheet in Embodiment 1 of the present invention;

[0031] Figure 6 for Figure 5 Enlarged view of point C in the middle;

[0032] Figure 7 This is a schematic diagram of the reinforcing rib in Embodiment 2 of the present invention. Detailed Implementation

[0033] The following detailed description illustrates the specific implementation method:

[0034] The reference numerals in the accompanying drawings include: tab adhesive 1, main body 2, buffer 3, ramp 4, electrode 5, and reinforcing rib 6.

[0035] Example 1

[0036] Example 1 is basically as follows Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, a magnesium battery tab is provided with tab adhesive 1. Specifically, the tab adhesive 1 is configured the same as in the prior art, and will not be described again in this embodiment. Below the tab adhesive 1, there are four main body parts 2, and the length of any one of the main body parts 2 is L. In this embodiment, 8mm≤L≤15mm.

[0037] A buffer section 3 is provided between each two adjacent main body sections 2. All buffer sections 3 have the same length, and their thickness is less than the thickness of the main body section 2. The centerline of the buffer section 3 coincides with the centerline of the main body section 2. The difference in thickness between the buffer section 3 and the main body section 2 is D. n The distance between the bottom of any main body 2 and the top of the adjacent main body 2 below it is L0. The lengths of the four main body 2 are L1, L2, L3 and L4, respectively. In this embodiment, D / 10 ≤ D n ≤D / 4, 5mm≤L0≤(1 / 4)*(L1+L2+L3+L4). Several reinforcing ribs 6 are fixed on the buffer section 3. The reinforcing ribs 6 include rings; specifically, in this embodiment, the reinforcing ribs 6 are circular. The reinforcing ribs 6 allow the buffer section 3 to maintain a smaller thickness, thus improving flexibility while having greater strength. In actual implementation, the reinforcing ribs 6 can also adopt shapes such as quadrilaterals or triangles with their ends connected.

[0038] Two ramps 4 are provided at both ends of the buffer part 3, and the two ramps 4 are located on both sides of the buffer part 3 respectively. All ramps 4 are connected to the buffer part 3 at one end and to the adjacent main body part 2 at the other end. The included angle between the ramp 4 and the surface of the buffer part 3 is α. In this embodiment, 120°≤α≤150°.

[0039] The specific implementation process is as follows:

[0040] Combination Figure 5 and Figure 6As shown, when welding the electrode 5, the welding positions of the electrode 5 and the electrode tab are arranged sequentially from left to right, and distributed from the top and bottom sides of the electrode tab. The electrode 5 is welded to the middle of the main body 2. Before welding, the part of the electrode 5 to be welded is first attached to the bottom middle of the main body 2, and then laser welding is performed. After welding, the next electrode 5 is abutted against the top middle of the main body 2 on the right side and welded, and so on, alternating welding. During the welding process, the flexibility of the buffer part 3 allows the buffer part 3 to bend and deform, preventing the electrode tab from breaking, effectively improving the welding qualification rate. In actual welding tests, while ensuring welding strength, the number of electrode 5 layers that can be welded to the electrode tab of the present invention is greater than or equal to 10 layers, proving that the welding difficulty is lower and the welding qualification rate is higher.

[0041] Example 2

[0042] Based on Example 1, such as Figure 7 As shown, the reinforcing rib 6 in this embodiment is strip-shaped. Specifically, the reinforcing rib 6 is wavy and extends along the width direction of the buffer portion 3. In actual implementation, the reinforcing ribs 6 of both Embodiment 1 and Embodiment 2 can be used simultaneously. In this case, the annular reinforcing rib 6 can be independent of the strip-shaped reinforcing rib 6, or the annular reinforcing rib 6 can be fixed with one or more strip-shaped reinforcing ribs 6 to form a Q-shaped reinforcing rib 6. Apart from this, the welding method in this embodiment is the same as that in Embodiment 1, and will not be described again in this embodiment.

[0043] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A magnesium battery tab, characterized in that: It includes at least two main parts. The welding part between the electrode and the electrode tab is located on the main part. A buffer part is provided between two adjacent main parts. The thickness of the buffer part is less than the thickness of the main part. The center line of the buffer part coincides with the center line of the main part. A slope is provided between the buffer part and the main part. The angle between the slope and the surface of the buffer part is an obtuse angle. The length of any one of the main parts is L, 8mm≤L≤15mm. A reinforcing rib is fixed on the buffer part.

2. The magnesium battery tab according to claim 1, characterized in that: The angle between the slope and the buffer section is α, where 120°≤a≤150°.

3. A magnesium battery tab according to claim 1, characterized in that: The distance between adjacent main parts is L0, 5mm≤L0≤(1 / n)*(L1+L2+……+L n ), where n represents the number of main body parts, and L1, L2, and Ln are the lengths of the first main body part, the second main body part, and the nth main body part, respectively.

4. A magnesium battery tab according to claim 1, characterized in that: Reinforcing ribs include ring-shaped ones.

5. A magnesium battery tab according to claim 1, characterized in that: The reinforcing ribs are strip-shaped.

6. A magnesium battery tab according to claim 1, characterized in that: The reinforcing ribs are round or wavy.

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