Battery cell, battery and electric device

Abstract

The utility model discloses a kind of battery cell, battery and electric equipment, including at least 2 pole piece units sequentially laminated along the thickness direction of battery cell, each pole piece unit includes multiple layers of positive pole piece, multiple layers of negative pole piece and multiple layers of diaphragm sequentially laminated along the thickness direction of battery cell according to preset order, positive pole piece has positive lug, positive lug has the orthographic projection of the thickness direction of vertical battery cell, the orthographic projection of the positive lug of same pole piece unit mutually coincides, the orthographic projection of the positive lug of different pole piece unit is completely staggered;Negative pole piece has negative lug, negative lug has the orthographic projection of the thickness direction of vertical battery cell, the orthographic projection of the negative lug of same pole piece unit mutually coincides, the orthographic projection of the negative lug of different pole piece unit is completely staggered.The utility model, reduce the difficulty of lug bending and welding difficulty, improve heat dissipation efficiency, to solve the problem of poor heat dissipation and welding not firm caused by lug superposition, with the advantage of improving rate performance and cycle life.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery technology, and in particular to a battery cell, a battery and an electrical device. Background Technology

[0002] Lithium-ion batteries are increasingly used in electric vehicles and large power tools, and their performance directly affects the range and efficiency of these devices. Traditional battery cells typically consist of multiple layers of positive and negative electrode sheets stacked together, each layer with tabs for external connection. In existing technology, the tabs of the multiple positive electrode sheets are usually stacked together, bent, and then welded to external conductive components; similarly, the tabs of the multiple negative electrode sheets are also stacked together, bent, and then welded to external conductive components. However, this design has technical drawbacks: First, due to the large number of tab layers, bending is difficult, easily leading to tab deformation or breakage; second, during welding, the thickness of the multiple tab layers is significant, making it difficult for welding energy to fully penetrate, easily resulting in incomplete welds or weak welds; furthermore, the limited heat dissipation area after stacking multiple tabs leads to heat accumulation, severely affecting the battery's rate performance and cycle life. Utility Model Content

[0003] Therefore, this utility model provides a battery cell, battery and electrical equipment, which has the advantages of reducing the difficulty of bending and welding the tabs, improving heat dissipation efficiency and improving rate performance and cycle life.

[0004] To address the aforementioned technical problems, this utility model provides a battery cell comprising at least two electrode units stacked sequentially along the thickness direction of the cell. Each electrode unit includes multiple layers of positive electrode sheets, multiple layers of negative electrode sheets, and multiple layers of separator stacked in a predetermined order. The positive electrode sheet has a positive electrode tab, and the positive electrode tab has an orthographic projection perpendicular to the thickness direction of the cell. The orthographic projections of the positive electrode tabs of the same electrode sheet unit overlap with each other, and the orthographic projections of the positive electrode tabs of different electrode sheet units are completely offset. The negative electrode sheet has a negative electrode tab, and the negative electrode tab has an orthographic projection perpendicular to the thickness direction of the cell. The orthographic projections of the negative electrode tabs of the same electrode sheet unit overlap with each other, while the orthographic projections of the negative electrode tabs of different electrode sheet units are completely offset.

[0005] Furthermore, one end of the positive electrode tab along its first side length direction is connected to the positive electrode sheet, and the positive electrode tab has a first conductive connection area for connecting to an external conductive component. The dimension of the first conductive connection area along the first side length direction of the positive electrode tab is greater than the thickness of a single electrode sheet unit and less than the thickness of the battery cell.

[0006] Furthermore, one end of the negative electrode tab along its first side length direction is connected to the negative electrode sheet, and the negative electrode tab has a second conductive connection area for connecting to an external conductive component. The dimension of the second conductive connection area along the first side length direction of the negative electrode tab is greater than the thickness of a single electrode sheet unit and less than the thickness of the battery cell.

[0007] Furthermore, the positive electrode tabs of different electrode units are close to each other and connected to the same external conductive component.

[0008] Furthermore, the negative electrode tabs of different electrode units are close to each other and connected to the same external conductive component.

[0009] Furthermore, the negative electrode tab is trapezoidal, and the base of the trapezoidal negative electrode tab is connected to the negative electrode sheet.

[0010] Furthermore, the battery cell includes two electrode units, with the positive and negative tabs of each electrode unit bent toward the side where the other electrode unit is located.

[0011] Furthermore, the outermost layer of the battery cell is the separator, and the next outermost layer of the battery cell is the negative electrode sheet.

[0012] This utility model also provides a battery, including the aforementioned battery cell.

[0013] This utility model also provides an electrical device, including the aforementioned battery.

[0014] Compared with the prior art, the above-mentioned technical solution of this utility model has the following advantages: The battery cell, battery and electrical device of this utility model divide the battery cell into multiple electrode units located at different positions in the thickness direction. Each electrode unit has a set of positive electrode tabs and a set of negative electrode tabs, so that the tabs of different electrode units are completely staggered, reducing the thickness of each set of tabs, reducing the bending and welding difficulty of each set of tabs, and improving heat dissipation efficiency. This solves the problems of weak welding and poor heat dissipation caused by the overlapping of tabs in the prior art, and has the advantages of improving rate performance and cycle life. Attached Figure Description

[0015] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0016] Figure 1 This is a schematic diagram of the battery cell disclosed in Embodiment 1 of this utility model; Figure 2 This is a schematic diagram of the battery disclosed in Embodiment 1 of this utility model; Figure 3 This is a schematic diagram of the battery cell disclosed in Embodiment 2 of this utility model.

[0017] Explanation of reference numerals in the accompanying drawings: 1. Electrode unit; 11. Positive electrode tab; 111. First conductive connection area; 12. Negative electrode tab; 121. Second conductive connection area; 2. Housing; 3. Cover plate; 31. Positive electrode post; 32. Negative electrode post. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention.

[0019] Example 1: See Figure 1 As shown, this utility model provides an embodiment of a battery cell.

[0020] The battery cell includes at least two electrode units 1 stacked sequentially along its thickness direction. Each electrode unit 1 includes multiple positive electrode sheets (not shown in the figure), multiple negative electrode sheets (not shown in the figure), and multiple separators (not shown in the figure) stacked in a preset order. The aforementioned positive electrode sheet has a positive electrode tab 11, and the aforementioned positive electrode tab 11 has an orthographic projection perpendicular to the thickness direction of the battery cell. The orthographic projections of the positive electrode tabs 11 of the same electrode sheet unit 1 overlap with each other, and the orthographic projections of the positive electrode tabs 11 of different electrode sheet units 1 are completely offset. The aforementioned negative electrode sheet has a negative electrode tab 12, and the aforementioned negative electrode tab 12 has an orthographic projection perpendicular to the thickness direction of the battery cell. The orthographic projections of the negative electrode tab 12 of the same electrode sheet unit 1 coincide with each other, while the orthographic projections of the negative electrode tab 12 of different electrode sheet units 1 are completely offset.

[0021] In the above text, the positive electrode, negative electrode, and separator are the three key components constituting the core electrochemical system. They work together to store and release electrical energy and ensure the safe and stable operation of the battery cell. The positive electrode is the crucial site for oxidation (charging) and reduction (discharging) reactions within the battery cell. It functions to carry active materials, participate in electrochemical reactions, conduct current, and form a circuit. The negative electrode, corresponding to the positive electrode, is the core of ion reception and storage, storing ions, participating in reversible reactions, conducting current, and balancing charges. The separator is a porous thin film located between the positive and negative electrodes. It physically isolates the positive and negative electrodes, prevents short circuits, allows ions to pass through, and ensures the reaction proceeds.

[0022] The positive and negative electrodes of the battery cell are arranged alternately, with a separator between adjacent positive and negative electrodes. The orthographic projection of the positive electrode tab 11 coincides, meaning that the projected areas of all positive electrode tabs 11 within the same electrode unit 1 overlap on the plane perpendicular to the cell thickness. The orthographic projection of the negative electrode tab 12 coincides, meaning that the projected areas of all negative electrode tabs 12 within the same electrode unit 1 overlap on the plane perpendicular to the cell thickness. The orthographic projection of the positive electrode tab 11 is staggered, meaning that the projected areas of the positive electrode tabs 11 of different electrode units 1 do not overlap on the plane perpendicular to the cell thickness. The orthographic projection of the negative electrode tab 12 is staggered, meaning that the projected areas of the negative electrode tabs 12 of different electrode units 1 do not overlap on the plane perpendicular to the cell thickness.

[0023] Specifically, the battery cell is divided into multiple electrode units 1 stacked along the thickness direction, with the positive and negative tabs within each electrode unit forming independent connection points. When the tabs are bent, each electrode unit only needs to process its own internal tab layers, significantly reducing bending resistance. During the welding process, the tab groups of different electrode units can be welded to different areas of the externally conductive components due to their staggered projections, avoiding interlayer interference. In terms of heat dissipation, the staggered tab groups form multiple independent heat dissipation surfaces, and heat is conducted outward through the tabs in different projection areas.

[0024] Through the above technical solution, the positive electrode tabs 11 of the same electrode unit 1 overlap with each other, and the negative electrode tabs 12 overlap with each other. The positive electrode tabs 11 of different electrode units 1 are completely staggered, and the negative electrode tabs 12 are completely staggered. This effectively reduces the mechanical stress when the tabs are bent and avoids the problem of insufficient welding caused by the stacking of multiple electrode tabs. The staggered distribution of the tab groups forms multiple independent heat dissipation channels, significantly increasing the heat dissipation surface area and improving the thermal management performance under high-rate charge and discharge conditions.

[0025] In this embodiment, the positive electrode tab 11 is connected to the positive electrode sheet at one end along its first side length direction. The positive electrode tab 11 has a first conductive connection area 111 for connecting to an external conductive component. The size of the first conductive connection area 111 along the first side length direction of the positive electrode tab 11 is greater than the thickness of a single electrode sheet unit 1 and less than the thickness of the battery cell.

[0026] The negative electrode tab 12 is connected to the negative electrode sheet at one end along its first side length direction. The negative electrode tab 12 has a second conductive connection area 121 for connecting to an external conductive component. The dimension of the second conductive connection area 121 along the first side length direction of the negative electrode tab 12 is greater than the thickness of a single electrode sheet unit 1 and less than the thickness of the battery cell.

[0027] In the above description, both the positive and negative electrode tabs have a first side and a second side. The length of the first side is the first side length, and the length of the second side is the second side length. The positive electrode tab 11 is connected to the positive electrode plate at one end along its first side length, and the negative electrode tab 12 is connected to the negative electrode plate at one end along its first side length. The first conductive connection area 111 refers to the area on the positive electrode tab 11 used for physical connection with external conductive components. The dimension of the first conductive connection area 111 in the first side length direction is L1. The second conductive connection area 121 refers to the area on the negative electrode tab 12 used for physical connection with external conductive components. The dimension of the second conductive connection area 121 in the first side length direction is L2. By setting L1 and L2 to be greater than the thickness of a single electrode unit 1, the area of ​​the first conductive connection area 111 and the second conductive connection area 121 is larger than that of the prior art.

[0028] With the above technical solution, the areas of the first conductive connection area 111 and the second conductive connection area 121 are relatively large. On the one hand, this reduces the contact resistance between the electrode and the external conductive component and improves the conductivity. On the other hand, it disperses the current load and reduces the risk of local overheating. Moreover, it can increase the mechanical connection strength between the electrode and the external conductive component and improve the structural reliability.

[0029] In this embodiment, the positive electrode tabs 11 of different electrode units 1 are close to each other and connected to the same external conductive component, and the negative electrode tabs 12 of different electrode units 1 are close to each other and connected to the same external conductive component.

[0030] In the above text, "positive electrode tabs 11 are close to each other" means that the positive electrode tabs 11 of different electrode units 1 are spatially adjacent but not overlapping. "Connected to the same external conductive component" means that the positive electrode tabs 11 of different electrode units 1 are soldered to different areas of the same conductive component. "Negative electrode tabs 12 are close to each other" means that the negative electrode tabs 12 of different electrode units 1 are spatially adjacent but not overlapping. "Connected to the same external conductive component" means that the negative electrode tabs 12 of different electrode units 1 are soldered to different areas of the same conductive component.

[0031] The above scheme connects all the positive electrode tabs 11 to the same external conductive component and all the negative electrode tabs 12 to the same external conductive component, which facilitates subsequent external connections.

[0032] In this embodiment, the battery cell includes two electrode units 1, and the positive electrode tab 11 and the negative electrode tab 12 of each electrode unit 1 are bent toward the side where the other electrode unit 1 is located.

[0033] In the above text, the two electrode units 1 are the first electrode unit and the second electrode unit, respectively. The positive and negative electrode tabs of the first electrode unit are bent toward the side where the second electrode unit is located, and the positive and negative electrode tabs of the second electrode unit are bent toward the side where the first electrode unit is located.

[0034] With the above technical solution, the positive electrode tab 11 and negative electrode tab 12 of each electrode unit 1 are bent toward the side where the other electrode unit 1 is located, and the tabs are more easily bent to the top of the cell.

[0035] In this embodiment, the outermost layer of the battery cell is the separator, and the next outermost layer of the battery cell is the negative electrode sheet.

[0036] In the above description, the battery cell includes multiple first electrode assemblies and a second electrode assembly stacked sequentially. Each first electrode assembly includes a separator-negative electrode-separator-positive electrode stacked sequentially, and the second electrode assembly includes a separator-negative electrode-separator. Thus, the outermost layer of the battery cell is the separator, and the next outermost layer is the negative electrode.

[0037] With the above technical solution, the outermost layer of the battery cell is a separator, and the next outermost layer of the battery cell is the negative electrode sheet, which helps to protect the electrode sheet and ensure insulation safety.

[0038] See Figure 2 The image shows a battery that includes the aforementioned battery cell.

[0039] As described above, the battery includes a casing 2, the aforementioned battery cell, and a cover plate 3. The battery cell is housed within the casing 2. The cover plate 3 closes the opening of the casing 2. The cover plate 3 has a positive terminal 31 and a negative terminal 32. The positive terminal 31 is directly connected to the positive electrode tab or via an adapter, and the negative terminal 32 is directly connected to the negative electrode tab or via an adapter. The positive terminal 31 and the negative terminal 32 are connected to the external circuitry to provide power.

[0040] The following section describes the electrical equipment, including the batteries mentioned above.

[0041] The aforementioned electrical equipment can include automobiles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Automobiles can be gasoline-powered vehicles, natural gas-powered vehicles, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the aforementioned electrical equipment.

[0042] Example 2: See Figure 3 This embodiment discloses another embodiment of the battery cell.

[0043] In this embodiment, the negative electrode tab 12 is trapezoidal, and the bottom edge of the trapezoidal negative electrode tab 12 is connected to the negative electrode sheet.

[0044] The negative electrode tab is typically made of copper foil. Copper foil is relatively soft, resulting in poor mechanical properties at the root of the negative electrode tab, making it prone to breakage. The trapezoidal shape of the negative electrode tab mentioned above refers to its overall geometric shape, narrower at the top and wider at the bottom. This can be achieved using an isosceles trapezoid or a right trapezoid, with the base longer than the top. The base connection refers to welding the base of the trapezoidal structure to the edge of the negative electrode plate, thus increasing the contact line length between the tab root and the electrode plate to form a stable mechanical connection interface.

[0045] By using the above technical solution, the negative electrode tab 12 is set in a trapezoidal shape to improve the support force at the root of the negative electrode tab and prevent the root of the tab from breaking.

[0046] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A battery cell, characterized in that, The battery cell comprises at least two electrode units stacked sequentially along its thickness direction. Each electrode unit includes multiple layers of positive electrode sheets, multiple layers of negative electrode sheets, and multiple layers of separator stacked in a predetermined order along the thickness direction of the battery cell. The positive electrode sheet has a positive electrode tab, and the positive electrode tab has an orthographic projection perpendicular to the thickness direction of the cell. The orthographic projections of the positive electrode tabs of the same electrode sheet unit overlap with each other, and the orthographic projections of the positive electrode tabs of different electrode sheet units are completely offset. The negative electrode sheet has a negative electrode tab, and the negative electrode tab has an orthographic projection perpendicular to the thickness direction of the cell. The orthographic projections of the negative electrode tabs of the same electrode sheet unit overlap with each other, while the orthographic projections of the negative electrode tabs of different electrode sheet units are completely offset.

2. The battery cell according to claim 1, characterized in that, The positive electrode tab is connected to the positive electrode sheet at one end along its first side length direction. The positive electrode tab has a first conductive connection area for connection with an external conductive component. The dimension of the first conductive connection area along the first side length direction of the positive electrode tab is greater than the thickness of a single electrode sheet unit and less than the thickness of the battery cell.

3. The battery cell according to claim 1, characterized in that, The negative electrode tab is connected to the negative electrode sheet at one end along its first side length direction. The negative electrode tab has a second conductive connection area for connecting to an external conductive component. The dimension of the second conductive connection area along the first side length direction of the negative electrode tab is greater than the thickness of a single electrode sheet unit and less than the thickness of the battery cell.

4. The battery cell according to claim 1, characterized in that, The positive electrode tabs of different electrode units are close to each other and connected to the same external conductive component.

5. The battery cell according to claim 1, characterized in that, The negative electrode tabs of different electrode units are close to each other and connected to the same external conductive component.

6. The battery cell according to claim 1, characterized in that, The negative electrode tab is trapezoidal, and the base of the trapezoidal negative electrode tab is connected to the negative electrode sheet.

7. The battery cell according to claim 1, characterized in that, The battery cell includes two electrode units, and the positive and negative tabs of each electrode unit are bent toward the side where the other electrode unit is located.

8. The battery cell according to claim 1, characterized in that, The outermost layer of the battery cell is the separator, and the next outermost layer of the battery cell is the negative electrode plate.

9. A battery, characterized in that, Includes the battery cell described in any one of claims 1 to 8.

10. An electrical appliance, characterized in that, Includes the battery as described in claim 9.

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