Battery cell and electric device

Abstract

The present application relates to the technical field of batteries. Provided are a battery cell and an electric device. In the present application, the battery cell comprises a cell body and a connecting piece. The cell body is provided with a plurality of stacked tabs, the plurality of tabs forming a pre-welding region by means of ultrasonic welding. The connecting piece comprises a first connecting portion, a bending portion and a second connecting portion which are connected in sequence, wherein the bending portion has at least two separated sub-layers, such that the connecting piece can bend at the bending portion. The pre-welding region is connected to the first connecting portion by means of ultrasonic welding, and the second connecting portion is configured for connecting to the tabs and an external circuit. In this way, the welding quality and welding strength between the tabs and the connecting piece can be improved, thereby improving the quality of the battery cell.

Description

Single battery and electrical device

[0001] This application claims priority to Chinese Patent Application No. 202423152224.2, filed on December 19, 2024, entitled "Single Battery and Electric Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and in particular to a single cell battery and an electrical device. Background Technology

[0003] With the development of new energy technologies, energy storage batteries have developed rapidly. An energy storage battery typically contains one or more individual cells, which supply power to electrical devices.

[0004] To reduce the size of energy storage batteries and improve the user experience of electrical devices equipped with energy storage batteries, the capacity density of individual batteries is constantly being increased.

[0005] However, as the capacity density of individual cells increases, the number of layers of positive and negative electrodes in a single cell gradually increases, and consequently, the number of layers of tabs also increases. When the number of tab layers is large, welding defects are more likely to occur, which in turn affects the quality of the individual cell.

[0006] Utility Model Content

[0007] This application provides a single-cell battery and an electrical device that can reduce the problem of poor welding at the tabs when there are many layers of tabs, thereby improving the quality of the single-cell battery.

[0008] In a first aspect, this application provides a single-cell battery, including a cell body and a connecting piece. The cell body has multiple stacked tabs, which are ultrasonically welded to form a pre-welded area. The connecting piece includes a first connecting portion, a bent portion, and a second connecting portion connected in sequence. The bent portion has at least two mutually separated sub-layers, allowing the connecting piece to be bent at the bent portion.

[0009] The pre-welded area is connected to the first connection part by ultrasonic welding, and the second connection part is used to connect the electrode tab and the external circuit.

[0010] In this embodiment, multiple tabs can be welded together first by ultrasonic welding, and then the connecting piece can be ultrasonically welded to the welded tabs. This can improve the welding quality and welding strength between the tabs and the connecting piece, thereby improving the quality of the single cell.

[0011] Furthermore, the bend in the connector facilitates the connection between the tab and the external circuit, improving the ease of soldering.

[0012] Optionally, the single cell has intersecting first and second directions, and the pre-welded area is welded to the first connection portion to form a final welded area, which covers the pre-welded area.

[0013] In the first direction, the dimensions of the pre-soldering area relative to both ends are L1, and the dimensions of the final soldering area relative to both ends are L2. In the second direction, the dimensions of the pre-soldering area relative to both ends are W1, and the dimensions of the final soldering area relative to both ends are W2.

[0014] Among them, L1, L2, W1, and W2 satisfy: L2≤L1, W2≤W1.

[0015] With the above settings, the welding range of the final welding zone can fall within the pre-welding zone, so that the electrode tab and the first connecting part can be fully connected, improving the reliability of the connection between the electrode tab and the first connecting part.

[0016] Optionally, the single cell also has a third direction. The connecting piece includes multiple metal sheets stacked along the third direction, the multiple metal sheets are compositely connected at the first connecting portion and the second connecting portion, but not composite at the bending portion, and the multiple metal sheets and the portion corresponding to the bending portion form a sub-layer.

[0017] With the above configuration, the connecting piece can be formed from multiple metal sheets. These multiple metal sheets can then be connected at different locations to form a first connecting portion, a second connecting portion, and a bent portion.

[0018] Optionally, in at least part of the first connection portion, multiple metal sheets are connected by ultrasonic welding or molecular diffusion welding.

[0019] This allows multiple metal sheets to form the first connecting part.

[0020] Optionally, the single cell also has a first direction and a second direction, wherein the first direction, the second direction, and the third direction intersect each other, and multiple metal sheets are welded at the first connection to form a first solder area. In the first direction, the dimensions of the pre-soldering area at opposite ends are L1, and the dimensions of the first solder area at opposite ends are L3. In the second direction, the dimensions of the pre-soldering area at opposite ends are W1, and the dimensions of the first solder area at opposite ends are W3.

[0021] Among them, L1, L3, W1, and W3 satisfy: L1≤L3, W1≤W3.

[0022] Thus, the overall size of the first soldering area can be greater than or equal to the overall size of the pre-soldering area.

[0023] When welding the first connecting part and the electrode tab, welding can be carried out in the first soldering area and the pre-welding area to weld the connecting piece after composite connection to the electrode tab part that has been ultrasonically welded into a whole, thereby improving the reliability of the connection between the electrode tab and the first connecting part.

[0024] Optionally, the individual battery cell also includes a terminal post, which is connected to the second connection portion to connect the tab and external circuitry.

[0025] In this way, the connecting piece can connect the tab and the terminal, so that the tab can transmit the current inside the single cell to the external circuit through the connecting piece and the terminal.

[0026] Optionally, in at least part of the second connection, multiple metal sheets are connected by ultrasonic welding or molecular diffusion welding.

[0027] This allows multiple metal sheets to form a second connecting part.

[0028] Optionally, the individual cell also has a first direction and a second direction, with the first direction, the second direction, and the third direction intersecting each other. Multiple metal sheets are welded to the second connection portion to form a second solder area, and the electrode post is welded to the second connection portion to form a third solder area, which covers the second solder area.

[0029] In the first direction, the dimensions of the second solder area relative to its two ends are L4, and the dimensions of the third solder area relative to its two ends are L5. In the second direction, the dimensions of the second solder area relative to its two ends are W4, and the dimensions of the third solder area relative to its two ends are W5.

[0030] Among them, L4, L5, W4, and W5 satisfy: L5 < L4, W5 < W4.

[0031] Thus, when welding the second connecting part and the pole, a third welding area can be formed on the second welding area to weld the composite connecting piece to the pole.

[0032] Optionally, the connecting piece is a single-layer structure, and the part of the connecting piece corresponding to the bending part is provided with at least one hollow area, and the part of the bending part located on both sides of the hollow area forms a sub-layer.

[0033] Thus, the presence of the hollowed-out area at the bending point reduces the material of the connecting piece, making it easier to bend the sub-layer, and thus facilitating the change of the relative position between the first connecting part and the second connecting part.

[0034] Secondly, this application provides an electrical device including any of the single-cell batteries mentioned in the first aspect above.

[0035] The beneficial effects of the electrical device provided in the second aspect and the various possible designs of the second aspect can be found in the first aspect and the various possible implementations of the first aspect, and will not be repeated here. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 is a schematic diagram of a single battery cell according to an embodiment of this application.

[0038] Figure 2 is a magnified view of part A in Figure 2.

[0039] Figure 3 is a schematic diagram of a single battery cell without connecting tabs according to an embodiment of this application.

[0040] Figure 4 is a magnified view of part B in Figure 3.

[0041] Figure 5 is a schematic diagram of a connecting piece according to an embodiment of this application.

[0042] Figure 6 is a schematic diagram of a pre-soldering area formed on a tab according to an embodiment of this application.

[0043] Figure 7 is a schematic diagram of the connection between a tab and a connecting piece according to an embodiment of this application.

[0044] Figure 8 is a top view of a connecting piece according to an embodiment of this application.

[0045] Figure 9 is a schematic diagram of a single cell battery with terminals provided in an embodiment of this application.

[0046] Figure 10 is a magnified view of point C in Figure 9.

[0047] Figure 11 is a schematic diagram of the connection between a pole and a connecting piece according to an embodiment of this application.

[0048] Figure 12 is a cross-sectional view of a single battery cell according to an embodiment of this application.

[0049] Figure 13 is a magnified view of part D in Figure 12.

[0050] Reference numerals: 100: Single cell; 10: Cell body; 20: Tab; 201: Pre-welding area; 202: Final welding area; 30: Connecting piece; 31: First connecting part; 311: First soldering area; 32: Bending part; 33: Second connecting part; 331: Second soldering area; 332: Third soldering area; 40: Terminal post; X: First direction; Y: Second direction; Z: Third direction. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims and drawings of this application are intended to cover non-exclusive inclusion.

[0053] The term "embodiment" as used herein 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 the phrase "embodiment" 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.

[0054] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists, A and B exist simultaneously, or B exists. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0055] The directional terms appearing in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the current limiting module of this application. For example, in the description of this application, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0056] Furthermore, the terms "first," "second," etc., in the specification and claims of this application or in the aforementioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0057] In the description of this application, unless otherwise stated, "multiple" means two or more (including two), and similarly, "multiple groups" means two or more (including two groups).

[0058] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, "connection" or "linkage" in mechanical structures can refer to a physical connection, such as a fixed connection, for example, a connection fixed by a partition, such as a connection fixed by screws, bolts, or other partitions; a physical connection can also be a detachable connection, such as a snap-fit ​​or interlocking connection; a physical connection can also be an integral connection, such as a connection formed by welding, bonding, or integral molding. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. In circuit structures, "connection" or "linkage" can refer not only to a physical connection but also to an electrical connection or a signal connection. For example, it can be a direct connection, i.e., a physical connection, or an indirect connection through at least one intermediate element, as long as the circuit is connected; it can also refer to the internal connection of two elements. A signal connection can refer not only to a signal connection through a circuit but also to a signal connection through a medium, such as radio waves. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0059] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0060] For example, an embodiment of this application proposes an electrical device, which includes a single battery 100 as shown in Figures 1 and 2.

[0061] The electrical device is equipped with a circuit system, and the individual battery 100 can be installed inside the electrical device and connected to the interface of the circuit system.

[0062] Thus, the single cell 100 can serve as an energy source for the electrical device, providing the necessary electrical energy so that the device can operate normally without an external power source.

[0063] In an electrical device equipped with the single battery 100 proposed in this application, the connection between the single battery 100 and the circuit system is more reliable, which can make the power transmission smoother, reduce the possibility of output power and voltage instability of the single battery 100 affecting the normal operation of the electrical device, and reduce the possibility of leakage, short circuit and other problems.

[0064] It should be noted that, in the embodiments of this application, the electrical device can be a new energy vehicle, an electric vehicle, a computer, a mobile phone, etc. The specific type of electrical device is not specifically limited in the embodiments of this application.

[0065] The single-cell battery 100 provided in the embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0066] Referring to Figures 1 to 4, this application provides a single-cell battery 100, including a cell body 10 and a connecting piece 30. The cell body 10 has multiple stacked tabs 20, which are ultrasonically welded to form a pre-welded area 201.

[0067] As shown in Figure 5, the connecting piece 30 includes a first connecting portion 31, a bending portion 32 and a second connecting portion 33 connected in sequence. The bending portion 32 has at least two mutually separated sub-layers so that the connecting piece 30 can be bent at the bending portion 32.

[0068] The pre-welded area 201 is connected to the first connecting part 31 by ultrasonic welding, and the second connecting part 33 is used to connect the tab 20 and the external circuit.

[0069] In this application, the single cell 100 includes a cell body 10 and a connecting piece 30. The connecting piece 30 can serve as an intermediate transmission component for connecting the cell body 10 to an external circuit, allowing the current inside the single cell 100 to be transmitted to the external circuit through the connecting piece 30 to supply power to the external circuit.

[0070] When the single cell 100 is used in an electrical device, the external circuit can be the circuit system in the electrical device.

[0071] In this embodiment, the cell body 10 is provided with tabs 20, and the cell body 10 can be connected to the connecting piece 30 through the tabs 20. In this way, the tabs 20 can guide the current inside the single cell 100 to the connecting piece 30, which in turn facilitates the connecting piece 30 to transmit the current to the external circuit to provide power to the external circuit.

[0072] Multiple tabs 20 are stacked on the battery cell body 10. When connecting the tabs 20 and the connecting piece 30, the multiple tabs 20 can be ultrasonically welded first, so that the welded multiple tabs 20 are connected to each other in the pre-welding area 201 to form a whole, thereby improving the tightness between the multiple tabs 20.

[0073] Afterwards, the pre-welded area 201 of the tab 20 can be ultrasonically welded to the connecting piece 30, which can improve the welding quality and welding strength between the tab 20 and the connecting piece 30, and reduce the possibility that multiple tabs 20 and the connecting piece 30 are not easy to weld, or that defects such as incomplete welding or bursting are likely to occur during welding.

[0074] In this embodiment, the connecting piece 30 includes a first connecting portion 31, a bent portion 32, and a second connecting portion 33. Specifically, the electrode tab 20 can be welded to the first connecting portion 31 by ultrasonic welding.

[0075] The second connecting part 33 is used to connect to an external circuit. The first connecting part 31, the bending part 32 and the second connecting part 33 are connected in sequence. In this way, the first connecting part 31 and the second connecting part 33 can be connected through the bending part 32 to realize the connection between the tab 20 and the external circuit.

[0076] Since the bending portion 32 is connected between the first connecting portion 31 and the second connecting portion 33 and has at least two mutually separate sub-layers, the bending portion 32 has strong bendability.

[0077] With the above configuration, the connecting piece 30 can be bent through the bending portion 32 to change the relative position of the first connecting portion 31 and the second connecting portion 33. When connecting the first connecting portion 31 and the electrode tab 20, the connecting piece 30 can be bent according to welding requirements, improving the convenience of welding.

[0078] In addition, the design of multiple sub-layers in the bending section 32 allows for a high degree of freedom in the bending section 32, reducing the risk of breakage of the connecting piece 30 and ensuring high reliability.

[0079] In summary, in the embodiments of this application, multiple tabs 20 can be welded together by ultrasonic welding. Then, when connecting the tabs 20 and the connecting piece 30, the connecting piece 30 can be directly connected to the welded tabs 20, which can improve the welding quality and welding strength between the tabs 20 and the connecting piece 30, thereby improving the quality of the single cell 100.

[0080] Furthermore, the bend 32 in the connecting piece 30 facilitates the connection between the tab 20 and the external circuit, improving the ease of soldering.

[0081] It should be noted that, in the embodiments of this application, the welding between the multiple tabs 20 and the welding between the tabs 20 and the first connecting part 31 are all completed by ultrasonic welding.

[0082] Ultrasonic welding is a welding technique that uses ultrasonic waves. Ultrasonic waves act on the contact surfaces of the parts to be welded, causing friction and raising the temperature from room temperature to a plastic state. Then, under the high-frequency vibration of the ultrasonic waves, the parts are pressed together, causing the metal molecules to diffuse and interweave, thus completing the weld.

[0083] Compared with laser welding and other methods, ultrasonic welding does not require high temperature and solder, which can reduce the welding of the electrode 20 itself and the molten pool generated during the welding process between the electrode 20 and the first connection part 31. This makes it easier for impurities such as gas and dust to affect the molten pool, thereby reducing the welding quality.

[0084] That is, in the embodiments of this application, setting two ultrasonic welding at the electrode tab 20 can reduce the influence of the external environment on the welding quality and improve the welding quality.

[0085] Furthermore, laser welding primarily utilizes a high-energy-density laser beam, resulting in minimal or no pressure on the workpiece. However, if laser welding is used to weld multiple tabs 20, or to weld the tabs 20 to the first connecting portion 31, the welding of the multiple tabs 20 or the welding of the tabs 20 to the first connecting portion 31 may become unreliable.

[0086] This application uses ultrasonic welding to weld multiple tabs 20 and the tabs 20 to the first connecting part 31. Ultrasonic welding involves pressing the workpiece under pressure, which ensures close contact between the surfaces of the workpieces. Thus, when welding multiple tabs 20 or the tabs 20 to the first connecting part 31, the applied pressure is relatively large, which can further improve the welding quality.

[0087] It should also be noted that, in the embodiments of this application, a single battery cell 100 may be provided with one cell body 10, or multiple cell bodies 10 may be provided. Multiple cell bodies 10 can be connected in series or in parallel, which can effectively utilize the internal space of the single battery cell 100.

[0088] In the single cell 100 proposed in this application, the connection between the tab 20 and the connecting piece 30 is relatively reliable, which can largely avoid the occurrence of defects such as poor soldering and hole bursting.

[0089] Especially for single-cell batteries 100 with a large number of tabs 20, or single-cell batteries 100 with multiple cell bodies 10, the tabs 20 may be stacked in 70 or more layers. This application can reduce the welding difficulty, improve the welding quality, and reduce the possibility of poor welding of ultra-thick tabs 20.

[0090] In some embodiments, as shown in Figures 4, 6, and 7, the pre-soldering area 201 and the first connecting portion 31 can be welded to form the final soldering area 202. Thus, the tab 20 in the pre-soldering area 201 and the first connecting portion 31 can be connected in the final soldering area 202.

[0091] In this embodiment, the single cell 100 has intersecting first direction X and second direction Y. In the first direction X, the dimensions of the pre-welded area 201 at opposite ends are L1, and the dimensions of the final welded area 202 at opposite ends are L2. In the second direction Y, the dimensions of the pre-welded area 201 at opposite ends are W1, and the dimensions of the final welded area 202 at opposite ends are W2.

[0092] In this design, the final soldering area 202 covers the pre-soldering area 201, and L1, L2, W1, and W2 satisfy: L2≤L1, W2≤W1. Thus, the overall size of the pre-soldering area 201 can be larger than the overall size of the final soldering area 202.

[0093] With the above settings, the welding range of the final welding area 202 can fall within the pre-welding area 201, so that the tab 20 and the first connecting part 31 can be fully connected, thereby improving the reliability of the connection between the tab 20 and the first connecting part 31.

[0094] Furthermore, when welding the tab 20 to the first connecting part 31, the welding to the unconnected part of the tab 20 can be reduced, resulting in less connection between the first connecting part 31 and the pre-welded area 201, which may easily cause it to fall off during subsequent assembly or use.

[0095] It should be noted that the cross-sectional shape of the pre-welding area 201 and the final welding area 202 can be various, such as rectangular, trapezoidal, circular, etc., and can be adjusted according to the shape of the welding head.

[0096] It should also be noted that the first direction X can be perpendicular to the second direction Y, or the angle between the first direction X and the second direction Y can be 65°, 78°, 82°, 96° or 99.1°, etc. The specific positional relationship between the first direction X and the second direction Y is not specifically limited in this embodiment of the application.

[0097] In the embodiments of this application, the connecting piece 30 can be configured in different ways, and the following two examples will be used for specific description.

[0098] In the first method, the connecting piece 30 is a single-layer structure, and the part of the connecting piece 30 corresponding to the bending part 32 is provided with at least one hollow area, and the part of the bending part 32 located on both sides of the hollow area forms a sub-layer.

[0099] With the above configuration, a hollow area can be provided in the middle of the connecting piece 30 to form a bent portion 32. On both sides of the bent portion 32, no hollow area is provided, and this part of the connecting piece 30 remains a single-layer structure, which can respectively form the first connecting portion 31 and the second connecting portion 33.

[0100] Thus, the presence of the hollow area at the bending portion 32 reduces the material of the connecting piece 30, making it easier to bend the sublayer, and consequently facilitating changes in the relative positions of the first connecting portion 31 and the second connecting portion 33. This, in turn, facilitates the welding of the tab 20 to the first connecting portion 31.

[0101] It should be noted that the cutout area can be set in different ways.

[0102] For ease of explanation, the different directions of the connecting piece 30 are defined here. The distribution direction of the first connecting part 31 and the second connecting part 33 is the length direction of the connecting piece 30.

[0103] The connecting piece 30 also has a top surface and a bottom surface, and the connecting piece 30 can be welded to the electrode tab 20 through the top surface or the bottom surface. The distribution direction of the top surface and the bottom surface is the thickness direction of the connecting piece 30. The width direction of the connecting piece 30 is perpendicular to both the thickness direction and the length direction of the connecting piece 30.

[0104] When the connecting piece 30 is connected to the tab 20, the length direction of the connecting piece 30 is collinear with the second direction Y, and the width direction of the connecting piece 30 is collinear with the first direction X.

[0105] At the bend 32, the hollow area can penetrate the connecting part along the width direction of the connecting piece 30 to form multiple sub-layers distributed along the thickness direction of the connecting piece 30.

[0106] Alternatively, at the bend 32, the cutout area can extend along the length of the connecting piece 30 to form multiple sub-layers distributed along the width of the connecting piece 30.

[0107] Of course, the hollowed-out area can also be set in other ways. The specific setting of the hollowed-out area is not specifically limited in this embodiment.

[0108] In addition, multiple hollow areas can be set to form more sub-layers, reducing the bending difficulty of the connecting piece 30.

[0109] For example, the number of cutout areas can be two, with two cutout areas spaced apart to form three sub-layers. Alternatively, the number of cutout areas can be three, with three cutout areas spaced apart to form four sub-layers. Of course, the number of cutout areas can also be one, and the specific number of cutout areas is not specifically limited in the embodiments of this application.

[0110] It should also be noted that, in the embodiments of this application, the connecting piece 30 can be a single layer of copper, aluminum or other metal. In order to reduce the possibility of damage to the connecting piece 30 during the welding process, the thickness of the connecting piece 30 can be between 0.8 and 1.5 mm, for example, 0.8 mm, 0.85 mm, 0.9 mm, 1 mm or 1.2 mm, etc. The specific material and thickness of the connecting piece 30 are not specifically limited in the embodiments of this application.

[0111] In the second method, the single cell 100 also has a third direction Z. When the connecting piece 30 is not bent, the direction from the first connecting portion 31 to the second connecting portion 33 intersects with the third direction Z. The connecting piece 30 includes a plurality of metal sheets stacked along the third direction Z. The plurality of metal sheets are compositely connected at the first connecting portion 31 and the second connecting portion 33, but are not composite at the bending portion 32. The portions of the plurality of metal sheets corresponding to the bending portion 32 form a sub-layer.

[0112] With the above configuration, the connecting piece 30 can be formed from multiple metal pieces. In this case, the multiple metal pieces can be connected at different positions to form a first connecting part 31, a second connecting part 33, and a bending part 32.

[0113] Specifically, multiple metal sheets can be compositely connected on opposite sides to form a first connecting portion 31 and a second connecting portion 33, respectively. The middle portion of the multiple metal sheets can remain unprocessed, maintaining a multi-layered design to form a sub-layer.

[0114] Thus, because the middle part of the connecting piece 30 has a multi-layered design, the mutual constraints between the layers in the middle part of the connecting piece 30 are small, making it easy to bend, which in turn facilitates the change of the relative position of the first connecting part 31 and the second connecting part 33. Therefore, it is convenient to weld the electrode tab 20 to the first connecting part 31.

[0115] It should be noted that the plane formed by the first direction X and the second direction Y can intersect with the third direction Z. As a preferred approach, the first direction X, the second direction Y, and the third direction Z can be perpendicular to each other to form a Cartesian coordinate system.

[0116] It should also be noted that, in this embodiment, the plurality of metal sheets forming the connecting piece 30 can be copper foil or aluminum foil. Copper foil and aluminum foil have good conductivity and flexibility, and are easy to process, which can meet the design requirements of the single cell 100.

[0117] Specifically, the connecting piece 30 can be formed of 8 layers of copper or aluminum foil with a thickness of 0.1 mm, or it can be formed of 7 layers of copper or aluminum foil with a thickness of 0.15 mm, or it can be formed of 4 layers of copper or aluminum foil with a thickness of 0.2 mm.

[0118] The specific material, thickness, and number of layers of the metal sheet in the connecting piece 30 are not specifically limited in this embodiment. They can be selected based on the parameters of the single cell 100 and the material of the tab 20.

[0119] Furthermore, when there are many layers of metal sheets, the multiple metal sheets forming the connecting piece 30 can also be different. For example, when there are 8 layers of metal sheets, some of the metal sheets can be copper foil, and the other parts can be aluminum foil.

[0120] At this time, in order to improve the reliability of the welding between the first connecting part 31 and the tab 20, the material of the outermost metal sheet can be the same as the material of the tab 20.

[0121] Thus, when welding the tab 20 and the connecting piece 30, the outermost metal piece has the same melting point as the tab 20, which facilitates welding.

[0122] In some embodiments, at least a portion of the first connection portion 31, multiple metal sheets can be connected by ultrasonic welding or molecular diffusion welding.

[0123] In this embodiment, multiple metal sheets can be joined together by ultrasonic welding or molecular diffusion welding to form a first connection portion 31.

[0124] Molecular diffusion welding is a welding method that uses high temperature and high pressure to allow atoms and molecules of the materials to be welded to permeate and diffuse into each other, forming tight atomic bonds.

[0125] The number of metal sheets in the connecting piece 30 is relatively small (compared to the number of layers in the tab 20), so molecular diffusion welding or ultrasonic welding can be used for welding, both of which can ensure welding quality.

[0126] When welding metal sheets using molecular diffusion welding, fewer layers of metal sheets are required to be welded, which reduces the possibility of insufficient diffusion of materials in multiple layers of metal sheets, thereby reducing the occurrence of problems such as incomplete welding.

[0127] In some embodiments, at least a portion of the second connection portion 33, multiple metal sheets can be connected by ultrasonic welding or molecular diffusion welding.

[0128] In this embodiment, multiple metal sheets can be joined together by ultrasonic welding or molecular diffusion welding to form a second connection portion 33.

[0129] Since the connecting piece 30 has a small number of metal sheets, molecular diffusion welding or ultrasonic welding can be used for welding, both of which can ensure welding quality.

[0130] In addition, in this embodiment of the application, the multilayer metal sheets at the first connecting part 31 can be all compositely connected, or only some of them can be connected.

[0131] That is, the parts corresponding to the multi-layer metal sheets and the first connecting part 31 can be welded together to increase the welding area and welding strength of the first connecting part 31, so as to reduce the possibility of poor welding quality when connecting the electrode tab 20 later.

[0132] Alternatively, a small area can be welded together in the portion of the multi-layered metal sheet corresponding to the first connecting part 31, while the other parts of the first connecting part 31 remain in a multi-layered structure. During subsequent welding of the tab 20, the tab 20 can be ultrasonically welded only to the portion welded together in the first connecting part 31.

[0133] Similarly, the multilayer metal sheets in the second connecting portion 33 can all be compositely connected, or only partially connected. For details, please refer to the above description of the first connecting portion 31; the embodiments of this application will not be repeated here.

[0134] In some embodiments, as shown in FIG5, multiple metal sheets can be welded at the first connecting portion 31 to form a first solder area 311. In this way, some of the metal sheets at the first connecting portion 31 can be connected together in the first solder area 311.

[0135] Referring to Figures 6 and 8, in the first direction X, the dimensions of the pre-soldering area 201 relative to its two ends are L1, and the dimensions of the first solder area 311 relative to its two ends are L3. In the second direction Y, the dimensions of the pre-soldering area 201 relative to its two ends are W1, and the dimensions of the first solder area 311 relative to its two ends are W3.

[0136] In this design, the first solder area 311 covers the pre-soldering area 201, and L1, L3, W1, and W3 can satisfy: L1≤L3, W1≤W3. Thus, the overall size of the first solder area 311 can be greater than or equal to the overall size of the pre-soldering area 201.

[0137] When welding the first connecting part 31 and the tab 20, welding can be performed on the first soldering area 311 and the pre-welding area 201 to weld the composite connecting piece 30 to the part of the tab 20 that has been ultrasonically welded into a whole, thereby improving the reliability of the connection between the tab 20 and the first connecting part 31.

[0138] It should be noted that the cross-sectional shape of the first solder area 311 can also be various, such as rectangular, trapezoidal, circular, etc.

[0139] In the embodiments of this application, as shown in Figures 5, 9 and 10, the single battery cell 100 may further include a terminal post 40, which is connected to the second connection portion 33 to connect the tab 20 and the external circuit through the terminal post 40.

[0140] In this embodiment, the terminal 40 can be connected to the second connecting part 33. In this way, the connecting piece 30 can connect the tab 20 and the terminal 40 so that the tab 20 can transmit the current inside the single cell 100 to the external circuit through the connecting piece 30 and the terminal 40.

[0141] In some embodiments, as shown in Figures 5 and 8, multiple metal sheets can be welded to the second connecting portion 33 to form a second solder area 331, and the electrode post 40 can be welded to the second connecting portion 33 to form a third solder area 332. Thus, some of the metal sheets at the second connecting portion 33 can be connected in the second solder area 331, and the electrode post 40 and the connecting piece 30 can be connected in the third solder area 332.

[0142] Referring to Figures 6, 8, and 11, in the first direction X, the dimensions of the second solder area 331 relative to its two ends are L4, and the dimensions of the third solder area 332 relative to its two ends are L5. In the second direction Y, the dimensions of the second solder area 331 relative to its two ends are W4, and the dimensions of the third solder area 332 relative to its two ends are W5.

[0143] In this design, the third solder area 332 covers the second solder area 331, and L4, L5, W4, and W5 can satisfy the following conditions: L5 < L4, W5 < W4. Thus, the overall size of the second solder area 331 can be larger than the overall size of the third solder area 332.

[0144] When welding the second connecting part 33 and the pole post 40, a third soldering area 332 can be formed on the second soldering area 331 to weld the composite connecting piece 30 to the pole post 40.

[0145] It should be noted that, compared with the tab 20, the pole post 40 generally has a more complex structure and a larger thickness. Therefore, when welding the pole post 40 and the second connecting part 33, laser welding is generally used for connection.

[0146] In actual connection, the pole post 40 is welded to the second solder area 331.

[0147] In this way, the laser welding equipment can initiate an arc and perform welding in the second welding area 331 to form a third welding area 332 that is smaller than the second welding area 331.

[0148] That is, the welding of the pole post 40 and the second connecting part 33 is actually carried out in the second soldering area 331, which makes the welding between the pole post 40 and the second connecting part 33 more reliable, reduces the possibility of the pole post 40 being connected to the non-composite metal sheet, and thus the connection between the pole post 40 and the connecting piece 30 being unreliable.

[0149] It should also be noted that the cross-sectional shape of the second solder area 331 and the third solder area 332 can also be various, such as rectangular, trapezoidal, circular, etc.

[0150] In the above description, this application has constrained the dimensional relationships between the pre-welding area 201, the final welding area 202, the first solder mark area 311, the second solder mark area 331, and the third solder mark area 332 to improve welding quality. To make this application clearer, the following description takes a single cell 100 with an overcurrent capacity of 800A to 1000A as an example.

[0151] The pre-soldering area 201 has a dimension L1 of 8mm in the first direction X and a dimension W1 of 40mm in the second direction Y. The final soldering area 202 has a dimension L2 of 6mm in the first direction X and a dimension W2 of 35mm in the second direction Y. The first solder mark area 311 has a dimension L3 of 10mm in the first direction X and a dimension W3 of 44mm in the second direction Y.

[0152] Thus, the size of the first soldering area 311 is larger than that of the pre-soldering area 201. When welding the tab 20 to the connecting part, the first soldering area 311 and the pre-soldering area 201 can be set opposite to each other, and then the final soldering area 202 can be formed inside the pre-soldering area 201. This allows the tab 20 that is ultrasonically welded to the connecting piece 30 to be a part of the tab 20 that has been ultrasonically welded into a whole.

[0153] The second solder area 331 can have a dimension L4 of 6mm in the first direction X and a dimension W4 of 44mm in the second direction Y. The third solder area 332 can have a dimension L5 of 1.5mm in the first direction X and a dimension W5 of 40mm in the second direction Y.

[0154] It is understood that the specific values ​​of the dimensions in the above embodiments are set for ease of understanding. In actual applications, in addition to current carrying capacity, other factors also affect the dimensions of the pre-soldering area 201, etc., and can be set according to the actual situation.

[0155] That is, in a single cell 100 with a current capacity of 800A to 1000A, the dimensions of the pre-welding area 201, the final welding area 202, the first soldering area 311, the second soldering area 331, and the third soldering area 332 are not limited to the above values, and can be selected according to the manufacturing process, welding parameters, etc.

[0156] For example, the dimension L1 of the pre-soldering area 201 in the first direction X can be 6mm, 8.5mm, 9.5mm, 10mm, etc., and the dimension W2 of the pre-soldering area 201 in the second direction Y can be 35mm, 38mm, 42mm, 45mm, etc.

[0157] For other single-cell batteries 100 with different current carrying capacities, specific settings can be made according to the specific parameters, manufacturing process, and welding parameters of the single-cell battery 100.

[0158] In this embodiment, multiple tabs 20 can be welded together by ultrasonic welding. Then, when connecting the tabs 20 and the connecting piece 30, the connecting piece 30 can be directly connected to the welded tabs 20, which can improve the welding quality and welding strength between the tabs 20 and the connecting piece 30, thereby improving the quality of the single cell 100.

[0159] Furthermore, the bend 32 in the connecting piece 30 facilitates the connection between the tab 20 and the external circuit, improving the ease of soldering.

[0160] Referring to Figures 12 and 13, the figures show the bent state of the connecting piece 30 after it is connected to the tab 20 and the post 40. The bending portion 32 in this application facilitates bending the connecting piece 30 to the illustrated state and avoids damage to the connecting piece 30.

[0161] Finally, it should be noted that the above embodiments are merely specific implementations of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A single-cell battery, characterized in that, The single battery cell includes: The battery cell body has multiple stacked tabs, and the multiple tabs are ultrasonically welded to form a pre-welded area. A connecting piece includes a first connecting portion, a bent portion, and a second connecting portion connected in sequence. The bent portion has at least two mutually separated sub-layers so that the connecting piece can be bent at the bent portion. The pre-welded area is connected to the first connecting part by ultrasonic welding, and the second connecting part is used to connect the electrode tab and the external circuit.

2. The single-cell battery according to claim 1, characterized in that, The single cell has intersecting first and second directions, and the pre-welding area is welded to the first connecting part to form a final welding area, which covers the pre-welding area. In the first direction, the dimensions of the pre-welding area relative to both ends are L1, and the dimensions of the final welding area relative to both ends are L2; In the second direction, the dimensions of the pre-welding area at opposite ends are W1, and the dimensions of the final welding area at opposite ends are W2; Among them, L1, L2, W1, and W2 satisfy: L2≤L1, W2≤W1.

3. The single-cell battery according to claim 1, characterized in that, The single battery cell also has a third orientation; The connecting piece includes a plurality of metal sheets stacked along the third direction. The plurality of metal sheets are compositely connected at the first connecting portion and the second connecting portion, but are not composite at the bending portion. The portions of the plurality of metal sheets corresponding to the bending portion form the sub-layer.

4. The single-cell battery according to claim 3, characterized in that, In at least a portion of the first connecting portion, a plurality of the metal sheets are connected by ultrasonic welding or molecular diffusion welding.

5. The single-cell battery according to claim 4, characterized in that, The single cell also has a first direction and a second direction, the first direction, the second direction and the third direction intersect each other, and multiple metal sheets are welded at the first connecting part to form a first solder area; In the first direction, the dimensions of the pre-welded area at opposite ends are L1, and the dimensions of the first solder area at opposite ends are L3; In the second direction, the dimensions of the pre-welded area at opposite ends are W1, and the dimensions of the first solder area at opposite ends are W3; Among them, L1, L3, W1, and W3 satisfy: L1≤L3, W1≤W3.

6. The single-cell battery according to claim 3, characterized in that, The single battery cell also includes a terminal post, which is connected to the second connection portion to connect the tab and the external circuit via the terminal post.

7. The single-cell battery according to claim 6, characterized in that, In at least a portion of the second connecting portion, a plurality of the metal sheets are connected by ultrasonic welding or molecular diffusion welding.

8. The single-cell battery according to claim 7, characterized in that, The single cell also has a first direction and a second direction, wherein the first direction, the second direction and the third direction intersect each other; Multiple metal sheets are welded together at the second connecting portion to form a second solder mark area, and the pole is welded to the second connecting portion to form a third solder mark area, the third solder mark area covering the second solder mark area; In the first direction, the dimensions of the second solder area at opposite ends are L4, and the dimensions of the third solder area at opposite ends are L5; In the second direction, the dimensions of the second solder area at opposite ends are W4, and the dimensions of the third solder area at opposite ends are W5; Among them, L4, L5, W4, and W5 satisfy: L5 < L4, W5 < W4.

9. The single-cell battery according to claim 1, characterized in that, The connecting piece is a single-layer structure, and at least one hollow area is provided on the part of the connecting piece corresponding to the bending part. The part of the bending part located on both sides of the hollow area forms the sub-layer.

10. An electrical appliance, characterized in that, The electrical device comprises a single battery as described in any one of claims 1-9.

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