Battery with spliced tabs and power utilization device

Abstract

The battery comprises a pole piece and a pole column, the pole piece comprises a multi-layer current collector and an active material layer arranged on the surface of the multi-layer current collector, and the multi-layer current collector comprises a polymer high-molecular base membrane and an aluminum layer arranged on at least one side surface of the polymer high-molecular base membrane; the aluminum layer is connected with the pole through the tab; one end, connected with the aluminum layer, of the tab is an aluminum section, one end, connected with the pole, of the tab is a copper section, and the aluminum section and the copper section are connected to form a spliced tab. According to the utility model, the aluminum layer in the multi-layer current collector is connected with the pole through the copper-aluminum spliced tab, so that the welding reliability of the multi-layer current collector and the battery pole is improved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a battery and power-consuming device with spliced ​​tabs. Background Technology

[0002] Multilayer current collectors have a "sandwich" structure, with an inner polymer layer (such as PET, PP, or PI) and two outer metal conductive layers (such as Al or Cu). Multilayer current collectors integrate the characteristics of lightweight, thin, and highly safe current collectors. The polymer layer in the middle provides effective resistance to puncture and short circuits, improving the battery's resistance to puncture and impact, and effectively reducing the risk of thermal runaway caused by external impacts. Furthermore, because polymers are significantly lighter and cheaper than metals, using multilayer current collectors as battery electrode raw materials can effectively reduce costs and weight. However, the presence of the polymer layer makes current conduction impossible in the thickness direction of the multilayer current collector, making electrode tab welding more difficult.

[0003] Currently, the tab welding of multilayer current collectors involves welding two pure metal foils onto the metal layers on both sides of the multilayer current collector using ultrasonic roll welding. Then, the other end of the pure metal foil welded to each multilayer current collector is welded to the battery terminal to achieve current output. This results in twice the number of metal foil layers actually welded to the battery terminal compared to traditional metal current collector electrode layers, requiring longer welding power, temperature, and time during the welding process.

[0004] Especially for positive electrode aluminum current collectors, aluminum has a low melting point. Excessive welding power, temperature and time can easily lead to aluminum explosion or over-welding, affecting the reliability of electrode tab welding. Moreover, with the increasing demand for improving the overall energy density of battery packs, the more electrode sheets or electrode coils and electrode tab layers there are in a single battery, the more difficult it is to weld. Utility Model Content

[0005] The purpose of this invention is to provide a battery and power device with spliced ​​tabs to improve the reliability of welding multilayer current collectors and battery terminals.

[0006] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0007] A battery with spliced ​​tabs includes an electrode sheet and a terminal post. The electrode sheet includes a multilayer current collector and an active material layer disposed on the surface of the multilayer current collector. The multilayer current collector includes a polymer base film and an aluminum layer disposed on at least one side surface of the polymer base film.

[0008] The aluminum layer is connected to the electrode post via a tab; the end of the tab connected to the aluminum layer is an aluminum segment, and the end of the tab connected to the electrode post is a copper segment. The aluminum segment and the copper segment are connected to form a spliced ​​tab.

[0009] To optimize the above technical solution, the specific measures also include:

[0010] The polymer base film has aluminum layers on both sides. The aluminum layer on one side is connected by a first aluminum segment and a first copper segment, and the aluminum layer on the other side is connected by a second aluminum segment and a second copper segment. The ends of the first copper segment and the second copper segment that are away from the aluminum segment are connected to each other.

[0011] In a direction perpendicular to the plane of the electrode, the electrode tab and the aluminum layer at least partially overlap to form an overlapping area, and a first welding area for connecting with the aluminum segment is provided in the overlapping area; the copper segment does not overlap with the first welding area.

[0012] No active material layer is provided on the aluminum layer in the overlapping area.

[0013] Furthermore, the copper segment does not overlap with the overlapping region.

[0014] Furthermore, the minimum distance between the copper segment and the overlapping area is greater than 2 cm.

[0015] The electrode post is provided with a second welding area for connecting with the copper segment, and the plane of the second welding area is set at an angle to the plane of the electrode sheet.

[0016] As a preferred embodiment, the tab has a bend, and the bend does not overlap with the splicing position of the tab.

[0017] As a preferred embodiment, the electrode post is a copper electrode post.

[0018] This utility model also protects an electrical device, including the aforementioned battery with spliced ​​tabs, wherein the battery terminals extend in the opposite direction to the direction of gravity in the electrical device.

[0019] Compared with the prior art, the beneficial effects of this utility model are:

[0020] This invention improves the welding reliability of the multilayer current collector and the battery terminal by connecting the aluminum layer in the multilayer current collector to the terminal via copper-aluminum splicing tabs. The aluminum layer of the multilayer current collector and the aluminum segment of the tab can be welded easily and efficiently, and the copper segment of the terminal and the tab can have better current carrying capacity, thus improving the welding effect between the tab and the terminal.

[0021] This invention also ensures battery effectiveness and avoids potential risks during use by adjusting the structure and position of the copper-aluminum spliced ​​tabs. Attached Figure Description

[0022] Figure 1 : A schematic diagram of the structure of a battery including spliced ​​tabs.

[0023] Figure 2 : A schematic diagram of the non-bending spliced ​​electrode tabs.

[0024] Figure 3 : A schematic diagram of the structure of the bent spliced ​​electrode tab.

[0025] In the diagram: 1-Electrode, 2-Electrode post, 3-Polymer base film, 4-Aluminum layer, 5-Aluminum segment, 6-Copper segment, 7-Overlapping area, 8-First welding area, 9-Second welding area, 10-Bend, 11-Copper-aluminum splice, 12-First aluminum segment, 13-Second aluminum segment, 14-First copper segment, 15-Second copper segment, 16-Active material layer. Detailed Implementation

[0026] The present invention will be further described in detail below through embodiments, but it should not be construed as the scope of the present invention being limited to the following embodiments. All technologies implemented based on the present invention fall within the scope of the present invention.

[0027] In the description of this utility model, it should also be noted that:

[0028] The orientations or positional relationships described herein are based on the relationships shown in the accompanying drawings and are used solely for the purpose of facilitating and simplifying the description of this utility model. They are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this utility model. Furthermore, terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0029] This utility model provides a battery with spliced ​​tabs, such as Figure 1 As shown, it includes an electrode 1 and an electrode post 2. The electrode 1 includes a multilayer current collector and an active material layer disposed on the surface of the multilayer current collector. The multilayer current collector includes a polymer base film 3 and an aluminum layer 4 disposed on at least one side surface of the polymer base film 3.

[0030] Aluminum layer 4 is connected to electrode post 2 via a tab; the end of the tab connected to aluminum layer 4 is aluminum segment 5, and the end of the tab connected to electrode post 2 is copper segment 6. Aluminum segment 5 and copper segment 6 are connected to form a spliced ​​tab, such as... Figure 2 As shown.

[0031] Specifically, aluminum segment 5 is welded to aluminum layer 4, and copper segment 6 is welded to pole post 2, which can be done using the following welding method:

[0032] The aluminum segment 5 and the aluminum layer 4 of the multi-layer current collector can be welded by ultrasonic roll welding. Since the same metal has the same melting point, the welding can be completed quickly and effectively during high-speed roll welding. The copper segment 6 is used to weld with the battery terminal 2. Copper has a high melting point and good conductivity. When multiple copper layers are stacked together and welded at high power, it is not easy to cause weld explosion or weld penetration.

[0033] The reason why this invention does not directly use pure copper tabs to weld with multilayer current collectors is that copper and aluminum have a large difference in melting point. If the welding temperature is low, only aluminum melts and the melting point of copper is not reached, resulting in low welding strength and failure to meet reliability standards. If the welding temperature is high, aluminum is very likely to explode when copper melts.

[0034] The preparation of the splicing tabs in this utility model can refer to the preparation method of copper and aluminum composite splicing parts in the prior art, such as the method mentioned in Chinese Patent No. CN107971339A. First, copper plates and aluminum plates are stacked in the thickness direction and rolled into composite copper-aluminum plates. Then, they are cut into strips and then rolled again after being placed upright. This yields copper-aluminum splicing foil with aluminum segment 5 and copper segment 6 connected. The splicing foil obtained in this way has reliable connection strength, good fusion effect at the copper-aluminum splice 11, and low interface resistance at the splice, which can meet the overcurrent requirements in the battery.

[0035] In most embodiments, aluminum layers 4 are provided on both sides of the polymer base film 3. The aluminum layer 4 on one side is connected by a first aluminum segment 12 and a first copper segment 14, and the aluminum layer 4 on the other side is connected by a second aluminum segment 13 and a second copper segment 15. The ends of the first copper segment 14 and the second copper segment 15 that are away from the aluminum segment 5 are connected to each other.

[0036] In the direction perpendicular to the plane of electrode 1, the electrode tab and the aluminum layer 4 at least partially overlap to form an overlapping region 7. The overlapping region 7 does not have an active material layer, and a first welding area 8 for connecting with the aluminum segment 5 is provided in the overlapping region 7; the copper segment 6 does not overlap with the first welding area 8.

[0037] Furthermore, copper segment 6 does not overlap with overlapping region 7. Even further, the minimum distance between copper segment 6 and overlapping region 7 is greater than 2 cm.

[0038] The reason why this invention avoids the overlap between the copper segment 6 and the aluminum layer 4 is that, in the battery, the surface of the aluminum layer 4 has an active material layer, which fully wets the electrolyte. If the copper segment 6 overlaps or is close to this area, the contact point is very likely to be covered with electrolyte as well. Since copper and aluminum have different electrode potentials in the electrochemical series, when the two metals come into contact and are in an electrolyte environment, a miniature galvanic cell will be formed. In this galvanic cell, the metal with the lower electrode potential (aluminum) will dissolve as the anode. Therefore, in order to ensure the effective life of the battery, it is necessary to avoid the contact point between the two metals being in an electrolyte environment.

[0039] The reason why this invention also avoids the copper segment 6 of the electrode tab from getting close to the aluminum layer 4 is that an insulating membrane is sandwiched between the battery electrodes 1. The insulating membrane also has good electrolyte wettability. In order to avoid short circuits between the positive and negative electrodes at the edges, the edge of the insulating membrane is usually set to protrude beyond the edge of the electrode 1, i.e., an overhang design. Therefore, the copper segment 6 and the overlapping area 7 must also maintain a certain distance to avoid the copper segment 6 from contacting the insulating membrane, which would lead to the formation of a micro battery, thereby reducing the risk of internal short circuit.

[0040] The electrode post 2 is provided with a second welding area 9 for connecting with the copper segment 6. In some embodiments, the plane of the second welding area 9 is set at an angle to the plane of the electrode 1, which can avoid stress concentration during the welding process and ensure welding quality.

[0041] In some embodiments, the electrode tab is provided with a bend 10, such as Figure 3 As shown, the bending point 10 does not overlap with the splicing position of the tab; the tab on the electrode plate 1 extends in a direction perpendicular to the welding surface of the tab on the electrode post 2, that is, the tab is welded to the electrode post 2 after bending.

[0042] This invention avoids the copper-aluminum splicing tabs from being spliced ​​at the bend 10. Bending may cause stress concentration at the splicing point, which may lead to damage or performance degradation of the tabs. Such damage may be breakage, deformation, or poor connection between the tabs and the electrode 1, thereby affecting the overall performance and safety of the battery.

[0043] In the embodiments of this utility model, the bending point 10 is mainly located in the copper segment 6. In order to ensure the structural strength of the spliced ​​electrode tab, the distance between the copper segment 6 and the aluminum layer 4 can be made longer.

[0044] In some implementations, the electrode post 2 is a copper electrode post, which can improve the welding effect between the copper segment 6 and the electrode post 2, and copper has better current carrying capacity.

[0045] In other embodiments, the present invention also provides an electrical device including the battery with spliced ​​tabs as described above. In some embodiments, it includes an outer casing and batteries with spliced ​​tabs arranged inside the casing. The battery terminals 2 in the electrical device extend in the opposite direction to the direction of gravity, which ensures that the battery is upright in the battery pack or battery module, rather than upside down or flat. This can prevent electrolyte from seeping into the splicing area of ​​the copper-aluminum spliced ​​tabs and prevent the formation of micro-batteries.

[0046] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications, equivalent substitutions, and improvements made by those skilled in the art to the above embodiments without departing from the scope of the present utility model's technical solution and based on the technical essence of the present utility model shall still fall within the protection scope of the present utility model's technical solution.

Claims

1. A battery with spliced ​​tabs, comprising electrode plates and terminals, characterized in that: The electrode includes a multilayer current collector and an active material layer disposed on the surface of the multilayer current collector. The multilayer current collector includes a polymer base film and an aluminum layer disposed on at least one side surface of the polymer base film. The aluminum layer is connected to the electrode post via a tab; the end of the tab connected to the aluminum layer is an aluminum segment, and the end of the tab connected to the electrode post is a copper segment. The aluminum segment and the copper segment are connected to form a spliced ​​tab.

2. The battery with spliced ​​tabs according to claim 1, characterized in that: The polymer base film has aluminum layers on both sides. The aluminum layer on one side is connected by a first aluminum segment and a first copper segment, and the aluminum layer on the other side is connected by a second aluminum segment and a second copper segment. The ends of the first copper segment and the second copper segment that are away from the aluminum segment are connected to each other.

3. The battery with spliced ​​tabs according to claim 1, characterized in that: In a direction perpendicular to the plane of the electrode, the electrode tab and the aluminum layer at least partially overlap to form an overlapping area, and a first welding area for connecting with the aluminum segment is provided in the overlapping area; the copper segment does not overlap with the first welding area.

4. The battery with spliced ​​tabs according to claim 3, characterized in that: No active material layer is provided on the aluminum layer in the overlapping area.

5. The battery with spliced ​​tabs according to claim 3, characterized in that: The copper segment does not overlap with the overlapping area.

6. The battery with spliced ​​tabs according to claim 5, characterized in that: The minimum distance between the copper segment and the overlapping area is greater than 2 cm.

7. The battery with spliced ​​tabs according to claim 1, characterized in that: The electrode post is provided with a second welding area for connecting with the copper segment, and the plane of the second welding area is set at an angle to the plane of the electrode sheet.

8. The battery with spliced ​​tabs according to claim 7, characterized in that: The electrode tab has a bend, and the bend does not overlap with the splicing position of the electrode tab.

9. The battery with spliced ​​tabs according to claim 1, characterized in that: The electrode is a copper electrode.

10. An electrical device, characterized in that: The battery with spliced ​​tabs as described in any one of claims 1-9, wherein the battery terminals in the power-consuming device are arranged in the opposite direction to the direction of gravity.

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