Composite current collector, electrode, and battery module

Abstract

The utility model discloses a kind of composite current collector, electrode and battery module, comprising: substrate layer, including main part and from the main part side extension tab portion;First conductive layer, deposit in the main part and the one side of tab portion;Second conductive layer, deposit in the main part and the other side of tab portion;Wherein, the tab portion is opened with hollow structure along the thickness direction of the substrate layer, in the deposition process of the first conductive layer and the second conductive layer, the hollow structure is suitable for depositing conductive substance, to make the first conductive layer and the second conductive layer mutual conduction. By using the above structure, process is simple, processing is efficient, high yield, good performance, effectively improve the bonding force between conductive layer and substrate layer.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a composite current collector, electrode and battery module. Background Technology

[0002] As a crucial component of ion batteries, the current collector collects the current generated by the active materials in the battery to form a larger output current. The use of composite current collector structures can further improve energy density, toughness, and elongation, thereby optimizing production processes, increasing energy density per unit mass, and enhancing safety.

[0003] Existing composite current collectors use a polymer substrate layer in the middle, with metal conductive layers attached to both sides. Active materials are coated on the outer surface of each conductive layer to form electrodes, and the uncoated areas form tabs. Because the substrate layer is a polymer that is relatively insulated from the metal, the conductive layers on both sides of the substrate layer cannot directly conduct electricity after different tabs are welded together. This results in higher internal resistance and uneven current density distribution in actual use.

[0004] To avoid the above issues, during battery manufacturing, metal adapter plates are placed at the tabs of the composite current collector. These metal adapter plates are welded to the conductive layers on both sides of the tab, enabling conductivity between the two conductive layers. Multiple composite current collectors are then stacked, and the metal adapter plates are welded to the terminals. This structure has at least the following disadvantages: 1. It is cumbersome, inefficient, and costly; 2. The metal adapter plates facilitate current flow between the tabs and terminals, and the tabs are heavy, making them prone to folding into the battery during stacking, causing short circuits and reducing yield; 3. Existing composite current collectors also suffer from insufficient bonding between the conductive layer and the substrate layer.

[0005] Therefore, it is necessary to improve the existing technology to overcome the aforementioned defects. Utility Model Content

[0006] The purpose of this invention is to provide a composite current collector, electrode, and battery module.

[0007] The purpose of this utility model is achieved through the following technical solution: a composite current collector, comprising:

[0008] The substrate layer includes a main body portion and an electrode tab portion extending from the side of the main body portion;

[0009] A first conductive layer is deposited on one side of the main body and the tab.

[0010] A second conductive layer is deposited on the other side of the main body and the tab.

[0011] The tab portion has a perforated structure extending through the thickness direction of the substrate layer. During the deposition of the first conductive layer and the second conductive layer, conductive material is deposited within the perforated structure to enable the first conductive layer and the second conductive layer to conduct to each other.

[0012] Furthermore, the hollow structure includes multiple sets of holes, which are arranged side by side along the extension direction of the tab portion.

[0013] Furthermore, a boundary line is formed between the main body and the tab, the tab includes a first side away from the boundary line, each hole group includes a plurality of through holes arranged at equal intervals along a direction parallel to the boundary line, and there is a first spacing L1 between two adjacent through holes in the same hole group. In the direction from the boundary line to the first side, the first spacing L1 of each hole group decreases in a gradient.

[0014] Furthermore, in any two adjacent groups of holes, the first spacing L1 of the group of holes farther from the boundary line is reduced by 5%-10% relative to the first spacing L1 of the group of holes closer to the boundary line.

[0015] Furthermore, a boundary line is formed between the main body and the tab, the tab includes a first side away from the boundary line, and a second spacing L2 is provided between two adjacent hole groups. In the direction from the boundary line to the first side, each second spacing L2 decreases in a gradient.

[0016] Furthermore, in any two adjacent second spacings L2, the second spacing L2 farther from the boundary line is reduced by 5%-10% relative to the second spacing L2 closer to the boundary line.

[0017] Furthermore, a boundary line is formed between the main body and the electrode tab, the electrode tab includes a first side away from the boundary line, the distance between the hole group adjacent to the first side and the first side is 5mm to 40mm; and / or, the distance between the hole group adjacent to the boundary line and the boundary line is 2mm to 5mm.

[0018] Furthermore, each of the hole groups includes a plurality of through holes arranged at equal intervals along a direction parallel to the boundary line, and the diameter of each through hole is the same, with the diameter of the through hole being 15μm to 50μm.

[0019] This utility model provides an electrode, comprising:

[0020] The aforementioned composite current collector;

[0021] Active materials are respectively disposed on the outer surfaces of the first conductive layer and the second conductive layer of the composite current collector, and correspond to the main body.

[0022] In addition, this utility model also provides a battery module, including the aforementioned electrodes, wherein the number of electrodes is several and they are stacked.

[0023] Compared with the prior art, this utility model has the following beneficial effects: By creating a hollow structure through the tab, conductive material is deposited within the hollow structure while the first and second conductive layers are being deposited, achieving conductivity between the first and second conductive layers at the tab. Therefore, when manufacturing the battery, there is no need to set additional metal sheets to weld to the first and second conductive layers on both sides of the tab. The process is simple, efficient, and low-cost, and it greatly reduces sheet resistance and improves the rate performance of the battery. After eliminating the metal sheets, the tab does not need to conduct electricity through metal sheets. Its own weight is light, and it is not easy to fold into the battery during the stacking process, avoiding short circuits and improving the yield rate in the battery production process. Since conductive material is formed in the hollow structure, the first and second conductive layers are connected. The conductive material in the hollow structure forms anchor points, which improves the bonding force between the conductive layer and the substrate layer to a certain extent. Attached Figure Description

[0024] Figure 1 This is a cross-sectional schematic diagram of the stacked state of multiple composite current collectors of this utility model.

[0025] Figure 2 This is a top view of the substrate layer in this utility model.

[0026] Explanation of reference numerals in the attached figures:

[0027] 100, Substrate layer; 110, Main body; 120, Tab; 130, Boundary line; 140, First side; 150, Second side; 200, First conductive layer; 300, Second conductive layer; 400, Hollow structure; 410, Hole group; 411, Through hole; 500, Conductive material; 600, Active material. Detailed Implementation

[0028] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0029] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0030] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0031] Please see Figure 1 and Figure 2 As shown, a composite current collector corresponding to a preferred embodiment of the present invention includes a substrate layer 100, a first conductive layer 200, and a second conductive layer 300. The substrate layer 100 includes a main body portion 110 and a tab portion 120 extending from the side of the main body portion 110. The first conductive layer 200 is deposited on one side of the main body portion 110 and the tab portion 120, preferably on the entire surface. The second conductive layer 300 is deposited on the other side of the main body portion 110 and the tab portion 120, preferably on the entire surface.

[0032] In this embodiment, the tab portion 120 is provided with a hollow structure 400 through the thickness direction of the substrate layer 100. During the deposition of the first conductive layer 200 and the second conductive layer 300, the hollow structure 400 is suitable for depositing conductive material 500 so that the first conductive layer 200 and the second conductive layer 300 are interconnected.

[0033] This invention utilizes a perforated structure 400 at the tab 120. Simultaneously with the deposition of the first conductive layer 200 and the second conductive layer 300, a conductive material 500 is deposited within the perforated structure 400, achieving conductivity between the first conductive layer 200 and the second conductive layer 300 at the tab 120. Therefore, during battery manufacturing, there is no need for additional metal sheets to be welded to the first conductive layer 200 and the second conductive layer 300 on both sides of the tab 120. This process is simple, efficient, and low-cost, significantly reducing sheet resistance and improving the battery's rate performance. Eliminating the metal sheets eliminates the need for current collection in the tab 120, making it lightweight and less prone to folding into the battery during stacking, thus preventing short circuits and improving the yield rate in battery production. Furthermore, the conductive material 500 within the perforated structure 400 facilitates conductivity between the first conductive layer 200 and the second conductive layer 300, forming anchor points that enhance the bonding strength between the conductive layer and the substrate layer 100.

[0034] Furthermore, the substrate layer 100 is a polymer layer, specifically made from PET, PP, PI, or other thin films. The perforated structure 400 can be formed on the thin film using a pulsed laser, and the pulsed laser is not limited to infrared, green, and ultraviolet lasers. The first conductive layer 200 and the second conductive layer 300 can be made of conductive metals, preferably copper.

[0035] During processing, a perforated structure 400 can be first made on the thin film, and then a first conductive layer 200 and a second conductive layer 300 can be deposited on both sides of the thin film by magnetron sputtering and water plating respectively. When depositing the conductive layer, a continuous conductive material 500 will be deposited on the inner wall of the perforated structure 400, so that the first conductive layer 200 and the second conductive layer 300 are interconnected. Then, the thin film is cut by a cutting device to form a composite current collector with a main body 110 and an electrode 120.

[0036] Furthermore, the hollow structure 400 includes at least one group of holes 410, each group of holes 410 including at least one through hole 411, the axial direction of the through hole 411 being parallel to the thickness direction of the tab portion 120. The through hole 411 is preferably a circular hole to reduce dead angles and facilitate the deposition of the conductive material 500 at various locations on the inner wall of the through hole 411. Preferably, there are multiple groups of holes 410, arranged side-by-side along the extension direction of the tab portion 120. By providing multiple groups of holes 410, the number of through holes 411 can be increased, further improving the interconnectivity between the first conductive layer 200 and the second conductive layer 300, reducing sheet resistance, and simultaneously improving the bonding strength between the conductive layer and the substrate layer 100 through the conductive material 500 within the multiple groups of holes 410.

[0037] Furthermore, a boundary line 130 is formed between the main body 110 and the tab 120, and the tab 120 includes a first side 140 away from the boundary line 130. Two sets of holes 410 located on both sides of the tab 120 in the extending direction are respectively adjacent to the boundary line 130 and the first side 140. Each set of holes 410 includes a plurality of through holes 411 arranged at equal intervals along a direction parallel to the boundary line 130. The tab 120 has two second sides 150 parallel to the extending direction, arranged opposite to each other, and the through holes 411 at both ends of each set of holes 410 are respectively adjacent to different second sides 150. This makes the through holes 411 evenly distributed at various positions of the tab 120.

[0038] Preferably, adjacent through holes 411 of the same hole group 410 have a first spacing L1, and the first spacing L1 of each hole group 410 decreases in a gradient direction from the boundary line 130 to the first side 140. That is, in the direction from the boundary line 130 to the first side 140, among any two adjacent hole groups 410, the first spacing L1 of the hole group 410 farther from the boundary line 130 is smaller than the first spacing L1 of the hole group 410 closer to the boundary line 130. In this embodiment, the first spacing L1 specifically refers to the shortest straight-line distance between the axes of two adjacent through holes 411, which is parallel to the boundary line 130.

[0039] By adopting the above-mentioned progressively decreasing design, the first spacing L1 of the hole group 410 adjacent to the boundary line 130 is the largest, which ensures the strength requirements of the tab 120, prevents stress abrupt change between the tab 120 and the main body 110, and reduces the probability of crack formation. The further away from the boundary line 130 the hole group 410 is, the smaller its first spacing L1 is, and the more numerous and dense the number of through holes 411 are. The more conductive points are formed by the conductive material 500, the better the current carrying capacity between the first conductive layer 200 and the second conductive layer 300, the lower the sheet resistance, and the better the bonding force.

[0040] When the reduction in the first spacing L1 is small, the number of through holes 411 will be small, which is not conducive to the conduction of the first conductive layer 200 and the second conductive layer 300, and the conductivity will be reduced. If the reduction in the first spacing L1 is large, the through holes 411 near the boundary line 130 will be denser, and the through holes 411 further away from the boundary line 130 will become increasingly dense, which is not conducive to stress diffusion and will easily cause the tab 120 to crack under pressure.

[0041] Preferably, in this embodiment, in the direction from the boundary line 130 to the first side 140, the first spacing L1 decreases by 5%-10% step by step. That is, in any two adjacent hole groups 410, the first spacing L1 of the hole group 410 farther from the boundary line 130 is reduced by 5%-10% relative to the first spacing L1 of the hole group 410 closer to the boundary line 130. By limiting the above parameters, the reasonable arrangement of the through holes 411 can be ensured, while the conductivity and stress diffusion can be optimized.

[0042] Furthermore, a second spacing L2 exists between two adjacent hole groups 410, and the second spacing L2 decreases gradually in the direction from the boundary line 130 to the first side 140. That is, in the direction from the boundary line 130 to the first side 140, among any two adjacent hole groups 410, the second spacing L2 between the hole groups 410 farther from the boundary line 130 is smaller than the second spacing L2 between the hole groups 410 closer to the boundary line 130. In this embodiment, the hole group 410 has a center line that intersects perpendicularly with the axis of the through hole 411, and the center line is parallel to the boundary line 130. The second spacing L2 specifically refers to the shortest straight-line distance between the center lines of two adjacent hole groups 410, and this straight line is parallel to the extension direction of the tab portion 120.

[0043] Through the above design, the second spacing L2 between the two hole groups 410 adjacent to the boundary line 130 is maximized, which further ensures the strength requirements of the electrode tab 120, prevents stress changes, and reduces crack generation. The further away the hole group 410 is from the boundary line 130, the smaller the spacing between the hole groups 410 and the denser the through holes 411, which further ensures the number of through holes 411, improves the current carrying capacity, and enhances the bonding force.

[0044] When the second spacing L2 decreases significantly, the holes 410 become more densely packed, and the number of through holes 411 increases, resulting in insufficient anchoring force during welding, making it easy to fall off and affecting the overcurrent capability. If the second spacing L2 decreases slightly, the number of through holes 411 is less, which is not conducive to the conduction of the conductive layers on both sides, reducing the conductivity and resulting in a lower bonding strength.

[0045] Preferably, in this embodiment, in the direction from the boundary line 130 to the first side 140, the second spacing L2 decreases by 5%-10% in stages. That is, in any two adjacent second spacings L2, the second spacing L2 farther from the boundary line 130 decreases by 5%-10% compared to the second spacing L2 closer to the boundary line 130. By limiting the above parameters, the through holes 411 can be reasonably arranged, while the anchoring force, conductivity, and bonding force can be optimized.

[0046] Furthermore, if the distance between the hole group 410 adjacent to the first side 140 and the first side 140 is too large, it will lead to a reduction in the number of through holes 411, which is not conducive to improving the flow capacity. Since the through holes 411 of the hole group 410 at the first side 140 are relatively dense, if the distance is too small, the load-bearing capacity will be poor, which will easily lead to cracking at the first side 140 under pressure during welding.

[0047] Preferably, in this embodiment, the distance between the hole group 410 adjacent to the first side 140 and the first side 140 is 5mm to 40mm, specifically the minimum straight-line distance between the centerline of the hole group 410 and the first side 140. By limiting the above parameters, the current carrying capacity is ensured to be in the optimal state, while the tab 120 is not prone to cracking at the first side 140.

[0048] Furthermore, if the distance between the hole group 410 adjacent to the boundary line 130 and the boundary line 130 is too large, it will lead to a reduction in the number of through holes 411, which is not conducive to improving the overcurrent capability; if the distance is too small, stress differences will easily form at the boundary line 130 during welding or subsequent roll coating of active material 600, resulting in cracks or even breakage.

[0049] Preferably, in this embodiment, the distance between the hole group 410 adjacent to the boundary line 130 and the boundary line 130 is 2mm to 5mm, specifically the minimum straight-line distance between the center line of the hole group 410 and the boundary line 130. By limiting the above parameters, the current carrying capacity is ensured to reach the optimal state, while the tab 120 is less likely to crack at the boundary line 130.

[0050] Furthermore, if the diameter of the through hole 411 is too large, the through holes 411 of the hole group 410 adjacent to the first side 140 will be too large and relatively dense, resulting in insufficient anchoring force during welding, making them easy to fall off and affecting the overcurrent capacity. If the diameter of the through hole 411 is too small, it is not conducive to the deposition of metal into the through hole 411 when the conductive layer is plated, and the continuous metal cannot be formed in the hole wall, resulting in the metal in the through hole 411 being broken, affecting the conductivity of the upper and lower conductive layers.

[0051] Preferably, in this embodiment, the diameter of the through holes 411 in each hole group 410 is the same, and the diameter of the through holes 411 is 15μm to 50μm. By limiting the above parameters, it is possible to avoid the diameter of the through holes 411 being too large or too small, so as to ensure the welding anchoring force while ensuring reliable conductivity between the upper and lower conductive layers.

[0052] Furthermore, the present invention provides an electrode comprising an active material 600 and the aforementioned composite current collector, wherein the active material 600 is disposed on the outer surfaces of the first conductive layer 200 and the second conductive layer 300 of the composite current collector, and corresponds to the main body 110.

[0053] In addition, this utility model also provides a battery module, including the aforementioned electrodes, with a number of electrodes arranged in a stacked manner, and the tabs 120 of each electrode are welded together to form a battery cell.

[0054] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A composite current collector, characterized by, include: The substrate layer (100) includes a main body (110) and a tab (120) extending from the side of the main body (110). A first conductive layer (200) is deposited on one side of the main body (110) and the tab (120); A second conductive layer (300) is deposited on the other side of the main body (110) and the tab (120); The tab portion (120) has a perforated structure (400) extending through the thickness direction of the substrate layer (100). During the deposition of the first conductive layer (200) and the second conductive layer (300), the perforated structure (400) is suitable for depositing conductive material (500) so that the first conductive layer (200) and the second conductive layer (300) are interconnected.

2. The composite current collector as described in claim 1, characterized in that, The hollow structure (400) includes multiple hole groups (410), which are arranged side by side along the extension direction of the tab portion (120).

3. The composite current collector as described in claim 2, characterized in that, A boundary line (130) is formed between the main body (110) and the tab (120). The tab (120) includes a first side (140) away from the boundary line (130). Each hole group (410) includes a plurality of through holes (411) arranged at equal intervals along a direction parallel to the boundary line (130). There is a first spacing L1 between two adjacent through holes (411) in the same hole group (410). In the direction from the boundary line (130) to the first side (140), the first spacing L1 of each hole group (410) decreases in a gradient.

4. The composite current collector as described in claim 3, characterized in that, In any two adjacent hole groups (410), the first spacing L1 of the hole group (410) farther from the boundary line (130) is reduced by 5%-10% relative to the first spacing L1 of the hole group (410) closer to the boundary line (130).

5. The composite current collector as described in claim 2, characterized in that, A boundary line (130) is formed between the main body (110) and the tab (120). The tab (120) includes a first side (140) away from the boundary line (130). A second spacing L2 is provided between two adjacent hole groups (410). In the direction from the boundary line (130) to the first side (140), each second spacing L2 decreases in a gradient.

6. The composite current collector as described in claim 5, characterized in that, In any two adjacent second spacings L2, the second spacing L2 farther from the boundary line (130) is reduced by 5%-10% relative to the second spacing L2 closer to the boundary line (130).

7. The composite current collector as described in claim 2, characterized in that, A boundary line (130) is formed between the main body (110) and the electrode (120). The electrode (120) includes a first side (140) away from the boundary line (130). The distance between the hole group (410) adjacent to the first side (140) and the first side (140) is 5mm to 40mm; and / or, the distance between the hole group (410) adjacent to the boundary line (130) and the boundary line (130) is 2mm to 5mm.

8. The composite current collector as described in claim 3, characterized in that, Each of the hole groups (410) includes a plurality of through holes (411) arranged at equal intervals along a direction parallel to the boundary line (130). The diameter of each through hole (411) is the same, and the diameter of the through hole (411) is 15μm~50μm.

9. An electrode, characterized in that, include: The composite current collector as described in any one of claims 1 to 8; An active material (600) is disposed on the outer surface of the first conductive layer (200) and the second conductive layer (300) of the composite current collector, and corresponds to the main body (110).

10. A battery module comprising the electrodes as described in claim 9, wherein the number of electrodes is plurality and they are stacked.

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