Single battery and electric device

Abstract

The utility model provides a single battery and an electric device, and relates to the technical field of batteries. In the invention, the single battery comprises a battery cell body and a connecting piece, wherein a plurality of laminated tabs are arranged on the battery cell body, and the plurality of tabs form a pre-welding area through ultrasonic welding. The connecting piece comprises a first connecting part, a bending part and a second connecting part which are connected in sequence, and the bending part is provided with at least two separated sub-layers, so that the connecting piece can be bent at the bending part. Wherein the pre-welding area is connected with the first connecting part in an ultrasonic welding manner, and the second connecting part is used for connecting the tab and an external circuit. Therefore, the welding quality and the welding strength between the tabs and the connecting pieces can be improved, and the quality of the single battery can be further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a single battery and a power utilization device. BACKGROUND

[0002] With the development of new energy technology, energy storage batteries are developing rapidly. One or more single batteries are generally provided in an energy storage battery, and the single batteries are used to supply power to a power utilization device.

[0003] In order to reduce the volume of the energy storage battery and improve the user experience of the power utilization device installed with the energy storage battery, the capacity density of the single battery is also continuously improved.

[0004] However, with the increase of the capacity density of the single battery, the number of layers of the positive and negative electrode sheets in the single battery gradually increases, and therefore, the number of layers of the tabs also increases. When the number of layers of the tabs is large, the welding of the tabs is prone to poor welding, which affects the quality of the single battery. UTILITY MODEL CONTENT

[0005] The present application provides a single battery and a power utilization device, which can reduce the problem of poor welding at the tabs when the number of layers of the tabs is large, and improve the quality of the single battery.

[0006] In a first aspect, the present application provides a single battery, which comprises a battery core body and a connecting sheet. The battery core body is provided with a plurality of tabs arranged in layers, and the plurality of tabs are connected by ultrasonic welding to form a pre-welding area. The connecting sheet comprises a first connecting portion, a bending portion and a second connecting portion connected in sequence, and the bending portion has at least two sub-layers separated from each other, so that the connecting sheet can be bent at the bending portion.

[0007] The pre-welding area and the first connecting portion are connected by ultrasonic welding, and the second connecting portion is used to connect the tabs and an external circuit.

[0008] In the embodiments of the present application, the plurality of tabs can be first welded by ultrasonic welding, and then the connecting sheet and the welded tabs are ultrasonically welded, which can improve the welding quality and strength between the tabs and the connecting sheet, and thus the quality of the single battery can be improved.

[0009] In addition, the provision of the bending portion in the connecting sheet can also facilitate the connection of the tabs and the external circuit, and improve the convenience of welding.

[0010] Optionally, the single battery has a first direction and a second direction intersecting each other, the pre-welding area and the first connecting portion are welded to form a final welding area, and the final welding area covers the pre-welding area.

[0011] In the first direction, the size of the opposite ends of the pre-welding area is L1, and the size of the opposite ends of the final welding area is L2. In the second direction, the size of the opposite ends of the pre-welding area is W1, and the size of the opposite ends of the final welding area is W2.

[0012] L1, L2, W1, and W2 satisfy: L2≤L1 and W2≤W1.

[0013] Through the above setting, the welding range of the final welding area can fall within the pre-welding area, so that the tab and the first connecting part can be fully connected, improving the reliability of the connection between the tab and the first connecting part.

[0014] Optionally, the single battery also has a third direction. The connecting sheet includes a plurality of metal sheets stacked along the third direction, and the plurality of metal sheets are connected at the first connecting part and the second connecting part, and are not connected at the bending part. The plurality of metal sheets form a sub-layer corresponding to the bending part.

[0015] Through the above setting, the connecting sheet can be formed by a plurality of metal sheets. At this time, the plurality of metal sheets can form the first connecting part, the second connecting part, and the bending part through connection at different positions.

[0016] Optionally, in at least part of the first connecting part, the plurality of metal sheets are connected by ultrasonic welding or molecular diffusion welding.

[0017] In this way, the plurality of metal sheets can form the first connecting part.

[0018] Optionally, the single battery also has a first direction and a second direction, the first direction, the second direction, and the third direction intersect with each other, and the plurality of metal sheets are welded to form a first welding area at the first connecting part. In the first direction, the size of the opposite ends of the pre-welding area is L1, and the size of the opposite ends of the first welding area is L3. In the second direction, the size of the opposite ends of the pre-welding area is W1, and the size of the opposite ends of the first welding area is W3.

[0019] L1, L3, W1, and W3 satisfy: L1≤L3 and W1≤W3.

[0020] In this way, the overall size of the first welding area can be greater than or equal to the overall size of the pre-welding area.

[0021] When welding the first connecting part and the tab, welding can be performed in the first welding area and the pre-welding area to weld the connecting sheet after composite connection and the part of the tab welded by ultrasonic welding as a whole, improving the reliability of the connection between the tab and the first connecting part.

[0022] Optionally, the single battery also includes a pole, and the pole is connected to the second connecting part to connect the tab and an external circuit through the pole.

[0023] In this way, the connecting piece can realize the connection between the tab and the pole, so that the tab can transmit the current inside the single battery to the external circuit through the connecting piece and the pole.

[0024] Optionally, in the at least partial second connecting part, the plurality of metal pieces are connected by ultrasonic welding or molecular diffusion welding.

[0025] In this way, the plurality of metal pieces can form the second connecting part.

[0026] Optionally, the single battery also has a first direction and a second direction, the first direction, the second direction and the third direction intersect with each other. The plurality of metal pieces are welded to form a second welding mark area in the second connecting part, and the pole and the second connecting part are welded to form a third welding mark area, and the third welding mark area covers the second welding mark area.

[0027] In the first direction, the size of the second welding mark area relative to both ends is L4, and the size of the third welding mark area relative to both ends is L5. In the second direction, the size of the second welding mark area relative to both ends is W4, and the size of the third welding mark area relative to both ends is W5.

[0028] Among them, L4, L5, W4, W5 satisfy: L5 < L4, W5 < W4.

[0029] In this way, when welding the second connecting part and the pole, the third welding mark area can be formed on the second welding mark area to weld the connecting piece after composite connection and the pole.

[0030] Optionally, the connecting piece is a single-layer structure, and the connecting piece is provided with at least one hollow area corresponding to the bending part. The part of the bending part located on both sides of the hollow area forms a sub-layer.

[0031] In this way, at the bending part, the existence of the hollow area can reduce the material of the connecting piece, facilitate the bending of the sub-layer, and thus facilitate the change of the relative position of the first connecting part and the second connecting part.

[0032] In a second aspect, the application provides a kind of electric device, comprising the single battery of any one of the above first aspect.

[0033] The electric device provided in the above second aspect and each possible design of the above second aspect has the beneficial effects of the first aspect and each possible embodiment of the first aspect, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a schematic view of a single battery of an embodiment of the application.

[0035] Figure 2 It is Figure 2 It is a local enlarged view of A in the middle.

[0036] Figure 3 A schematic view of a single battery without a connecting piece according to an embodiment of the present application.

[0037] Figure 4 A partial enlarged view of B in the middle. Figure 3

[0038] Figure 5 A schematic view of a connecting piece according to an embodiment of the present application.

[0039] Figure 6 A schematic view of a tab with a pre-welding area according to an embodiment of the present application.

[0040] Figure 7 A schematic view of a tab connected with a connecting piece according to an embodiment of the present application.

[0041] Figure 8 A top view of a connecting piece according to an embodiment of the present application.

[0042] Figure 9 A schematic view of a single battery with a pole according to an embodiment of the present application.

[0043] Figure 10 A partial enlarged view of C in the middle. Figure 9

[0044] A schematic view of a pole connected with a connecting piece according to an embodiment of the present application. Figure 11

[0045] A sectional view of a single battery according to an embodiment of the present application. Figure 12

[0046] A partial enlarged view of D in the middle. Figure 13 Figure 12 BRIEF DESCRIPTION OF THE DRAWINGS

[0047] 100: single battery; 10: battery core body; 20: tab; 201: pre-welding area; 202: final welding area; 30: connecting piece; 31: first connecting part; 311: first welding mark area; 32: bending part; 33: second connecting part; 331: second welding mark area; 332: third welding mark area; 40: pole; X: first direction; Y: second direction; Z: third direction.

[0048] DETAILED DESCRIPTION

[0049] ​​​In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of the present application.

[0050] 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 belongs; the terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the use of the terms "including," "comprising," "having" and variations thereof herein is meant to encompass the inclusion of the recited elements but not the exclusion of others.

[0051] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. Those skilled in the art will appreciate that embodiments described herein can be combined with other embodiments.

[0052] The term "and / or", merely used as a description of associated objects, means that there can be three kinds of relations, for example, A and / or B, can mean that A exists, A and B exist, and B exists. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0053] The orientation words appearing in the following description are the directions shown in the drawings, and do not limit the specific structure of the flow limiting module of the present application. For example, in the description of the present application, the terms "center", "longitudinal", "transverse", "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 drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0054] In addition, the terms "first", "second", etc. in the specification and claims of the present application or the above drawings are used to distinguish different objects, and are not used to describe a specific order, and can explicitly or implicitly include one or more of the features.

[0055] In the description of the present application, the meaning of "a plurality of" is two or more (including two), and the meaning of "a plurality of groups" is two or more groups (including two groups).

[0056] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connection" and "connection" should be understood in a broad sense. For example, the "connection" or "connection" of the mechanical structure can mean a physical connection, such as a fixed connection, for example, a fixed connection by a spacer, such as a fixed connection by a screw, bolt or other spacer; the physical connection can also be a detachable connection, such as a mutual clamping or clamping connection; the physical connection can also be integrally connected, such as welding, bonding or integrally formed connection. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. The "connection" or "connection" of the circuit structure can mean electrical connection or signal connection, such as direct connection, that is, physical connection, or indirect connection through at least one intermediate element, as long as the circuit is connected, and the internal connection of two elements; signal connection can be signal connection through circuit, or signal connection through media medium, such as radio wave. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0057] It should be understood that the "one embodiment" or "an embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner.

[0058] For example, the present application provides a power consuming device, which comprises a single battery 100 as shown in Figure 1 and Figure 2 .

[0059] The power consuming device is provided with a circuit system, and the single battery 100 can be arranged inside the power consuming device and connected to the interface of the circuit system.

[0060] In this way, the single battery 100 can serve as the energy source of the power consuming device, providing the required power for the power consuming device to work normally without external power supply.

[0061] In the power consuming device provided with the single battery 100, the single battery 100 is reliably connected with the circuit system, the power transmission is smooth, the output power and voltage instability of the single battery 100 are reduced, the normal operation of the power consuming device is not affected, and the possibility of leakage and short circuit is reduced.

[0062] It should be noted that in the embodiments of the present application, the power consuming device can be a new energy vehicle, an electric vehicle, a computer, a mobile phone, etc. The specific type of the power consuming device is not limited in the embodiments of the present application.

[0063] The single battery 100 provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0064] Referring to Figures 1 to 4 The present application provides a single battery 100, which comprises a battery core body 10 and a connecting sheet 30. The battery core body 10 is provided with a plurality of tab ears 20 arranged in layers, and the plurality of tab ears 20 form a pre-welding area 201 through ultrasonic welding.

[0065] As shown in Figure 5 The connecting sheet 30 comprises a first connecting part 31, a bending part 32 and a second connecting part 33 connected in sequence. The bending part 32 has at least two sub-layers separated from each other, so that the connecting sheet 30 can be bent at the bending part 32.

[0066] The pre-welding area 201 is connected with the first connecting part 31 through ultrasonic welding, and the second connecting part 33 is used to connect the tab ear 20 and the external circuit.

[0067] In the present application, the single battery 100 comprises the battery core body 10 and the connecting sheet 30. The connecting sheet 30 can be used as an intermediate transmission component for connecting the battery core body 10 and the external circuit, so that the current in the single battery 100 can be transmitted to the external circuit through the connecting sheet 30 to supply power to the external circuit.

[0068] In the case of the single battery 100 applied in the power consuming device, the external circuit can be the circuit system in the power consuming device.

[0069] In the embodiments of the present application, the battery core body 10 is provided with the tab ear 20, and the battery core body 10 can be connected with the connecting sheet 30 through the tab ear 20. In this way, the tab ear 20 can guide the current in the single battery 100 to be transmitted to the connecting sheet 30, and then the connecting sheet 30 can transmit the current to the external circuit to realize power supply to the external circuit.

[0070] The plurality of tabs 20 are stacked on the battery cell body 10, and the plurality of tabs 20 can be ultrasonically welded first to form a whole in the pre-welding area 201, thereby improving the tightness between the plurality of tabs 20.

[0071] Then, the part of the pre-welding area 201 of the tab 20 can be ultrasonically welded with the connecting piece 30, which can improve the welding quality and strength between the tab 20 and the connecting piece 30, and reduce the phenomenon of false welding, hole blasting, etc. when the plurality of tabs 20 are welded with the connecting piece 30.

[0072] In the embodiment, the connecting piece 30 includes a first connecting part 31, a bending part 32, and a second connecting part 33. The tab 20 can be ultrasonically welded with the first connecting part 31.

[0073] The second connecting part 33 is used to connect the external circuit. The first connecting part 31, the bending part 32, and the second connecting part 33 are connected in sequence, so that 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.

[0074] Since the bending part 32 is connected between the first connecting part 31 and the second connecting part 33 and has at least two sub-layers separated from each other, the bending part 32 has strong bendability.

[0075] Through the above arrangement, the connecting piece 30 can be bent through the bending part 32 to change the relative position of the first connecting part 31 and the second connecting part 33. When the first connecting part 31 and the tab 20 are connected, the connecting piece 30 can be bent according to the welding needs to improve the convenience of welding.

[0076] In addition, the design of the plurality of sub-layers in the bending part 32 can also make the bending part 32 have high freedom, reduce the risk of fracture of the connecting piece 30, and have high reliability.

[0077] In summary, in the embodiment, the plurality of tabs 20 can be welded first by ultrasonic welding, and then the connecting piece 30 can be directly connected with the welded tabs 20 when the tabs 20 are connected with the connecting piece 30, which can improve the welding quality and strength between the tab 20 and the connecting piece 30, and further improve the quality of the single battery 100.

[0078] In addition, the arrangement of the bending part 32 in the connecting piece 30 can also facilitate the connection between the tab 20 and the external circuit, and improve the convenience of welding.

[0079] It should be noted that in the embodiments of the present application, the welding between the plurality of tabs 20 and the welding of the tabs 20 and the first connecting portion 31 are both completed by ultrasonic welding.

[0080] Ultrasonic welding is a welding technology using ultrasonic waves. The ultrasonic waves can act on the contact surface of the to-be-welded parts, causing the contact surface of the to-be-welded parts to generate friction and heat up from room temperature to a plastic state. Then, under the high-frequency vibration of the ultrasonic waves, the to-be-welded parts are pressed together, causing the metal molecules to diffuse and interleave, thus completing the welding.

[0081] Compared with laser welding and other methods, ultrasonic welding does not require high temperature and solder, which can reduce the molten pool in the welding process of the tabs 20 themselves and the welding of the tabs 20 and the first connecting portion 31, so that impurities such as gas and dust can easily affect the molten pool, thereby reducing the possibility of reducing the welding quality.

[0082] That is, in the embodiments of the present application, the two ultrasonic weldings at the tabs 20 can reduce the influence of the external environment on the welding quality and improve the welding quality.

[0083] In addition, laser welding mainly realizes welding through a high-energy-density laser beam, so the pressure on the to-be-welded parts is small or non-existent, which also makes the welding of the plurality of tabs 20 or the welding of the tabs 20 and the first connecting portion 31 unreliable.

[0084] However, the present application uses ultrasonic welding to weld the plurality of tabs 20 and the tabs 20 and the first connecting portion 31. Ultrasonic welding is to press the to-be-welded parts by pressure, which can make the surfaces of the to-be-welded parts tightly contact. In this way, when welding the plurality of tabs 20 or the tabs 20 and the first connecting portion 31, a larger pressure is applied, which can further improve the welding quality.

[0085] It should be further noted that in the embodiments of the present application, one battery cell body 10 can be arranged in the single battery 100, or a plurality of battery cell bodies 10 can be arranged. The plurality of battery cell bodies 10 can be connected in series or in parallel, which can effectively utilize the space inside the single battery 100.

[0086] In the single battery 100 proposed in the present application, the connection of the tabs 20 and the connecting pieces 30 is reliable, which can greatly avoid the occurrence of poor phenomena such as virtual welding and hole blasting.

[0087] Especially for the single battery 100 with a large number of tabs 20 or the single battery 100 with a plurality of battery cell bodies 10, the tabs 20 can be stacked to have 70 or more layers. The present application can reduce the welding difficulty, improve the welding quality, and reduce the possibility of poor welding of the ultrathick tabs 20.

[0088] In some embodiments, as shown in FIGS. 1-3, the first connecting part 31 can be welded to the tab 20 to form a terminal welding area 202. In this way, the tab 20 and the first connecting part 31 can be connected in the terminal welding area 202. Figure 4 、 Figure 6 and Figure 7 The tab 20 in the pre-welding area 201 and the first connecting part 31 can be welded to form a terminal welding area 202. In this way, the tab 20 in the pre-welding area 201 and the first connecting part 31 can be connected in the terminal welding area 202.

[0089] In the embodiments of the present application, the single battery 100 has a first direction X and a second direction Y intersecting each other. In the first direction X, the size of the pre-welding area 201 relative to both ends is L1, and the size of the terminal welding area 202 relative to both ends is L2. In the second direction Y, the size of the pre-welding area 201 relative to both ends is W1, and the size of the terminal welding area 202 relative to both ends is W2.

[0090] Wherein, the terminal welding area 202 covers the pre-welding area 201, and L1, L2, W1, W2 satisfy: L2≤L1, W2≤W1. In this way, the overall size of the pre-welding area 201 can be greater than the overall size of the terminal welding area 202.

[0091] Through the above setting, the welding range of the terminal 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, and the reliability of the connection between the tab 20 and the first connecting part 31 can be improved.

[0092] And when welding the tab 20 and the first connecting part 31, the possibility of welding to the unconnected part of the tab 20, which leads to less connection between the first connecting part 31 and the pre-welding area 201, can be reduced, and the first connecting part 31 is easy to fall off in the subsequent assembly or use process.

[0093] It should be noted that the cross-sectional shape of the pre-welding area 201 and the terminal welding area 202 can be various, for example, it can be rectangular, trapezoidal, circular, etc., which can be adjusted according to the shape of the welding head.

[0094] It should also be noted that the first direction X can be perpendicular to the second direction Y, or the included 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 limited in the embodiments of the present application.

[0095] In the embodiments of the present application, the connecting piece 30 can have different setting modes, which are specifically illustrated as follows.

[0096] Mode one, 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.

[0097] Through the above setting, the bending part 32 can be formed by setting the hollow region in the middle of the connecting sheet 30. On both sides of the bending part 32, no hollow region is set, and this part of the connecting sheet 30 is still a single-layer structure, and the first connecting part 31 and the second connecting part 33 can be formed respectively.

[0098] In this way, at the bending part 32, the presence of the hollow region can reduce the material of the connecting sheet 30, facilitate the bending of the sub-layers, and thus facilitate the change of the relative position of the first connecting part 31 and the second connecting part 33. Thus, the welding of the tab 20 and the first connecting part 31 can be facilitated.

[0099] It should be noted that the hollow region can be set in different ways.

[0100] For the convenience of description, different directions of the connecting sheet 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 sheet 30.

[0101] The connecting sheet 30 also has a top surface and a bottom surface, and the connecting sheet 30 can be welded with the 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 sheet 30. The width direction of the connecting sheet 30 is perpendicular to the thickness direction and the length direction of the connecting sheet 30.

[0102] In the case of connecting the connecting sheet 30 and the tab 20, the length direction of the connecting sheet 30 is collinear with the second direction Y, and the width direction of the connecting sheet 30 is collinear with the first direction X.

[0103] At the bending part 32, the hollow region can penetrate the connecting part along the width direction of the connecting sheet 30 to form a plurality of sub-layers distributed along the thickness direction of the connecting sheet 30.

[0104] Alternatively, at the bending part 32, the hollow region can extend along the length direction of the connecting sheet 30 to form a plurality of sub-layers distributed along the width direction of the connecting sheet 30.

[0105] Of course, the hollow region can also be set in other ways. The specific setting of the hollow region is not specifically limited in the embodiments of the present application.

[0106] In addition, the hollow region can be provided with a plurality of hollow regions to form more sub-layers and reduce the bending difficulty of the connecting sheet 30.

[0107] For example, the number of hollow regions can be 2, and the 2 hollow regions are distributed at intervals to form 3 sub-layers. Alternatively, the number of hollow regions can be 3, and the 3 hollow regions are distributed at intervals to form 4 sub-layers. Of course, the number of hollow regions can also be 1, and the specific number of hollow regions is not specifically limited in the embodiments of the present application.

[0108] It should be noted that, in the embodiments of the present application, the connecting piece 30 can be single-layer copper or aluminum or other metal, in order to reduce the possibility of damage to the connecting piece 30 in the welding process, the thickness of the connecting piece 30 can be between 0.8 to 1.5 mm, for example, 0.8 mm, 0.85 mm, 0.9 mm, 1 mm or 1.2 mm, etc. For the specific material and thickness of the connecting piece 30, the embodiments of the present application are not limited here.

[0109] Second, the single battery 100 also has a third direction Z, in the case where the connecting piece 30 is not bent, the direction of the first connecting part 31 to the second connecting part 33 intersects 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 connected in the first connecting part 31 and the second connecting part 33, and are not connected in the bending part 32. The part corresponding to the bending part 32 forms a sub-layer.

[0110] Through the above setting, the connecting piece 30 can be formed by a plurality of metal sheets. At this time, the plurality of metal sheets can form the first connecting part 31, the second connecting part 33 and the bending part 32 by connection at different positions.

[0111] Specifically, the two opposite sides of the plurality of metal sheets can be connected to form the first connecting part 31 and the second connecting part 33, respectively. The middle part of the plurality of metal sheets can not be processed and still maintain the multi-layer design to form a sub-layer.

[0112] In this way, since the middle part of the connecting piece 30 is designed as a multi-layer, the mutual constraint between the layers of the middle part of the connecting piece 30 is small, which is easy to bend, and thus the relative position of the first connecting part 31 and the second connecting part 33 can be changed. Thus, the welding of the tab 20 and the first connecting part 31 can be facilitated.

[0113] It should be noted that the plane formed by the first direction X and the second direction Y can intersect the third direction Z. As a preferred way, the first direction X, the second direction Y and the third direction Z can be perpendicular to each other to form a rectangular coordinate system.

[0114] It should be noted that, in the embodiments of the present application, the plurality of metal sheets forming the connecting piece 30 can be copper foil or aluminum foil. The copper foil and the aluminum foil have good electrical conductivity and softness, and are easy to process, which can meet the design requirements of the single battery 100.

[0115] Specifically, the connecting piece 30 can be formed by 8 layers of copper foil or aluminum foil with a thickness of 0.1 mm, or can be formed by 7 layers of copper foil or aluminum foil with a thickness of 0.15 mm, or can be formed by 4 layers of copper foil or aluminum foil with a thickness of 0.2 mm.

[0116] The specific material, thickness, and number of layers of the metal sheets in the connecting sheet 30 are not limited herein, and can be selected according to the parameters of the single battery 100 and the material of the tab 20.

[0117] In addition, when the number of layers of the metal sheets is large, the plurality of metal sheets forming the connecting sheet 30 can also be different. For example, when the number of layers of the metal sheets is 8, some of the metal sheets can be copper foil, and the other metal sheets can be aluminum foil.

[0118] At this time, in order to improve the reliability of the welding of the first connecting portion 31 and the tab 20, the material of the outermost metal sheet can be the same as that of the tab 20.

[0119] In this way, when the tab 20 and the connecting sheet 30 are welded, the outermost metal sheet and the tab 20 have the same melting point, which can facilitate welding.

[0120] In some embodiments, in at least part of the first connecting portion 31, the plurality of metal sheets can be connected by ultrasonic welding or molecular diffusion welding.

[0121] In the embodiments of the present application, the plurality of metal sheets can be connected by ultrasonic welding or molecular diffusion welding to form the first connecting portion 31.

[0122] The molecular diffusion welding is a welding method in which atoms and molecules of the materials to be welded penetrate and diffuse into each other under high temperature and high pressure to form a tight atomic bond.

[0123] The number of layers of the metal sheets in the connecting sheet 30 is small (compared to the number of layers of the tab 20), and therefore, molecular diffusion welding or ultrasonic welding can be selected for welding, both of which can ensure the welding quality.

[0124] For the welding of the metal sheets by molecular diffusion welding, the number of layers of the metal sheets to be welded is small, which can reduce the possibility that the materials of the plurality of metal sheets do not diffuse sufficiently, and in turn, reduce the occurrence of problems such as false welding.

[0125] In some embodiments, in at least part of the second connecting portion 33, the plurality of metal sheets can be connected by ultrasonic welding or molecular diffusion welding.

[0126] In the embodiments of the present application, the plurality of metal sheets can be connected by ultrasonic welding or molecular diffusion welding to form the second connecting portion 33.

[0127] The number of layers of the metal sheets in the connecting sheet 30 is small, and therefore, molecular diffusion welding or ultrasonic welding can be selected for welding, both of which can ensure the welding quality.

[0128] In addition, in the embodiment of the present application, the multi-layer metal sheet at the first connecting portion 31 can be connected in a composite manner, or only a part of the multi-layer metal sheet can be connected.

[0129] That is, the multi-layer metal sheet can be welded in a composite manner at the part corresponding to the first connecting portion 31, so as to increase the welding area and welding strength of the first connecting portion 31, so as to reduce the possibility of poor welding quality when the subsequent connecting tab 20 is welded.

[0130] Alternatively, a small area of the multi-layer metal sheet corresponding to the first connecting portion 31 can be welded, and other parts of the first connecting portion 31 still have a multi-layer structure. When the tab 20 is welded subsequently, the tab 20 can be ultrasonically welded only with the part of the first connecting portion 31 that is welded.

[0131] Similarly, the multi-layer metal sheet in the second connecting portion 33 can also be connected in a composite manner, or only a part of the multi-layer metal sheet can be connected. For details, reference can be made to the above description of the first connecting portion 31, and the embodiment of the present application will not be described herein.

[0132] In some embodiments, as shown in Figure 5 , a plurality of metal sheets can be welded to form a first welding mark area 311 at the first connecting portion 31. In this way, a part of the metal sheets at the first connecting portion 31 can be connected at the first welding mark area 311.

[0133] In combination with Figure 6 and Figure 8 , in the first direction X, the size of the pre-welding area 201 relative to both ends is L1, and the size of the first welding mark area 311 relative to both ends is L3. In the second direction Y, the size of the pre-welding area 201 relative to both ends is W1, and the size of the first welding mark area 311 relative to both ends is W3.

[0134] Wherein, the first welding mark area 311 covers the pre-welding area 201, and L1, L3, W1, W3 can satisfy: L1≤L3, W1≤W3. In this way, the overall size of the first welding mark area 311 can be greater than or equal to the overall size of the pre-welding area 201.

[0135] When welding the first connecting portion 31 and the tab 20, the first welding mark area 311 and the pre-welding area 201 can be welded in particular, so as to weld the composite-connected connecting sheet 30 and the part of the tab 20 that is welded as a whole by ultrasonic welding, and improve the reliability of the connection between the tab 20 and the first connecting portion 31.

[0136] It should be noted that the cross-sectional shape of the first welding mark area 311 can also be various, for example, it can be rectangular, trapezoidal, circular, etc.

[0137] In the embodiment of the present application, as shown in Figure 5 , Figure 9 andFigure 10 As shown, the single battery 100 can further include a pole 40 connected with the second connecting part 33 to connect the tab 20 and the external circuit through the pole 40.

[0138] In the embodiment of the present application, the pole 40 can be connected with the second connecting part 33, so that the connecting sheet 30 can realize the connection between the tab 20 and the pole 40, so that the tab 20 can transmit the current inside the single battery 100 to the external circuit through the connecting sheet 30 and the pole 40.

[0139] In some embodiments, as shown in Figure 5 and Figure 8 , a plurality of metal sheets can be welded to form a second welding area 331 at the second connecting part 33, and the pole 40 and the second connecting part 33 are welded to form a third welding area 332. In this way, part of the metal sheets at the second connecting part 33 can be connected at the second welding area 331, and the pole 40 and the connecting sheet 30 can be connected at the third welding area 332.

[0140] As shown in Figure 6 , Figure 8 and Figure 11 , in the first direction X, the size of the second welding area 331 relative to both ends is L4, and the size of the third welding area 332 relative to both ends is L5. In the second direction Y, the size of the second welding area 331 relative to both ends is W4, and the size of the third welding area 332 relative to both ends is W5.

[0141] Wherein the third welding area 332 covers the second welding area 331, L4, L5, W4, W5 can satisfy: L5 < L4, W5 < W4. In this way, the overall size of the second welding area 331 can be greater than the overall size of the third welding area 332.

[0142] When welding the second connecting part 33 and the pole 40, the third welding area 332 can be formed on the second welding area 331 to weld the connecting sheet 30 after composite connection and the pole 40.

[0143] It should be noted that compared with the tab 20, the pole 40 generally has a more complex structure and a larger thickness, so when welding the pole 40 and the second connecting part 33, a laser welding method is generally used for connection.

[0144] In actual connection, the pole 40 is welded to the second welding area 331.

[0145] In this way, the laser welding device can arc and weld at the second welding area 331 to form a third welding area 332 smaller than the second welding area 331.

[0146] That is, the welding between the pole piece 40 and the second connecting portion 33 is actually performed in the second welding area 331, which can make the welding between the pole piece 40 and the second connecting portion 33 more reliable, and reduce the possibility that the pole piece 40 and the un-combined connecting metal sheet are connected, resulting in unreliable connection between the pole piece 40 and the connecting sheet 30.

[0147] It should be further noted that the cross-sectional shape of the second welding area 331 and the third welding area 332 can also be various, for example, rectangular, trapezoidal, circular, and the like.

[0148] In the above description, the size relationship between the pre-welding area 201, the final welding area 202, the first welding area 311, the second welding area 331, and the third welding area 332 is constrained to improve the welding quality. In order to make the application clearer, the following description is taken as an example of a single battery 100 with an overcurrent capacity of 800A to 1000A.

[0149] The size L1 of the pre-welding area 201 in the first direction X can be 8mm, and the size W1 in the second direction Y can be 40mm. The size L2 of the final welding area 202 in the first direction X can be 6mm, and the size W2 in the second direction Y can be 35mm. The size L3 of the first welding area 311 in the first direction X can be 10mm, and the size W3 in the second direction Y can be 44mm.

[0150] In this way, the size of the first welding area 311 is larger than that of the pre-welding area 201, and when welding the pole piece 20 and the connecting portion, the first welding area 311 can be arranged opposite to the pre-welding area 201, and the final welding area 202 can be formed inside the pre-welding area 201, so that the pole piece 20 for ultrasonic welding with the connecting sheet 30 is part of the pole piece 20 that has been integrally formed by ultrasonic welding.

[0151] The size L4 of the second welding area 331 in the first direction X can be 6mm, and the size W4 in the second direction Y can be 44mm. The size L5 of the third welding area 332 in the first direction X can be 1.5mm, and the size W5 in the second direction Y can be 40mm.

[0152] It can be understood that the specific values of the dimensions in the above embodiments are specifically set for ease of understanding, and in actual application, in addition to the overcurrent capacity, other factors also affect the size of the pre-welding area 201 and the like, which can be set according to the actual situation.

[0153] That is, in the single battery 100 with an overcurrent capacity of 800A to 1000A, the sizes of the pre-welding area 201, the final welding area 202, the first welding area 311, the second welding area 331, and the third welding area 332 are not limited to the above values, and can be selected according to the manufacturing process, welding parameters, and the like.

[0154] For example, the size L1 of the pre-welding area 201 in the first direction X can also be 6 mm, 8.5 mm, 9.5 mm, 10 mm, etc., and the size W2 of the pre-welding area 201 in the second direction Y can be 35 mm, 38 mm, 42 mm, 45 mm, etc.

[0155] For other over-current capacity single batteries 100, specific parameters, manufacturing processes, and welding parameters of the single battery 100 can also be set according to the specific parameters, manufacturing processes, and welding parameters of the single battery 100.

[0156] In the embodiments of the present application, the plurality of tabs 20 can be welded together by ultrasonic welding first, and then when connecting the tabs 20 and the connecting piece 30, the connecting piece 30 can be directly connected with the welded tabs 20, which can improve the welding quality and strength between the tabs 20 and the connecting piece 30, and thus the quality of the single battery 100 can be improved.

[0157] In addition, the provision of the bending part 32 in the connecting piece 30 can also facilitate the connection of the tabs 20 and the external circuit, and improve the convenience of welding.

[0158] Referring to Figure 12 and Figure 13 , the bending state of the connecting piece 30 after connecting the tabs 20 and the pole 40 is shown. The provision of the bending part 32 in the present application can facilitate the bending of the connecting piece 30 to the state shown in the figure, and avoid the damage to the connecting piece 30.

[0159] Finally, it should be noted that the above embodiments are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A single cell, characterized by, The monomer battery comprises: a battery core body, a plurality of tabs are arranged on the battery core body in a stacked manner, and the plurality of tabs form a pre-welding area through ultrasonic welding; a connecting sheet comprising a first connecting portion, a bending portion, and a second connecting portion connected in sequence, the bending portion has at least two sub-layers separated from each other, so that the connecting sheet can be bent at the bending portion; the pre-welding area and the first connecting portion are connected through ultrasonic welding, and the second connecting portion is used for connecting the tabs and an external circuit.

2. The cell according to claim 1, wherein The monomer battery has a first direction and a second direction intersecting with each other, the pre-welding area and the first connecting portion are welded to form a final welding area, and the final welding area covers the pre-welding area; in the first direction, the size of the opposite ends of the pre-welding area is L1, and the size of the opposite ends of the final welding area is L2; in the second direction, the size of the opposite ends of the pre-welding area is W1, and the size of the opposite ends of the final welding area is W2; wherein L1, L2, W1, and W2 satisfy L2≤L1 and W2≤W1.

3. The cell according to claim 1, wherein The monomer battery also has a third direction; the connecting sheet comprises a plurality of metal sheets arranged in a stacked manner along the third direction, the plurality of metal sheets are connected at the first connecting portion and the second connecting portion, and are not connected at the bending portion, and the portions of the plurality of metal sheets corresponding to the bending portion form the sub-layers.

4. The cell according to claim 3, wherein In at least part of the first connecting portion, the plurality of metal sheets are connected through ultrasonic welding or molecular diffusion welding.

5. The cell according to claim 4, wherein The monomer battery also has a first direction and a second direction, the first direction, the second direction, and the third direction intersect with each other in pairs, and a plurality of metal sheets are welded at the first connecting portion to form a first welding mark area; in the first direction, the size of the opposite ends of the pre-welding area is L1, and the size of the opposite ends of the first welding mark area is L3; in the second direction, the size of the opposite ends of the pre-welding area is W1, and the size of the opposite ends of the first welding mark area is W3; wherein L1, L3, W1, and W3 satisfy L1≤L3 and W1≤W3.

6. The cell according to claim 3, wherein The monomer battery also comprises a pole, the pole is connected with the second connecting portion, so as to connect the tabs and the external circuit through the pole.

7. The cell according to claim 6, wherein In at least part of the second connecting portion, the plurality of metal sheets are connected through ultrasonic welding or molecular diffusion welding.

8. The cell according to claim 7, wherein The monomer battery also has a first direction and a second direction, the first direction, the second direction, and the third direction intersect with each other in pairs; a plurality of metal sheets are welded at the second connecting portion to form a second welding mark area, the pole and the second connecting portion are welded to form a third welding mark area, and the third welding mark area covers the second welding mark area; in the first direction, the size of the opposite ends of the second welding mark area is L4, and the size of the opposite ends of the third welding mark area is L5; in the second direction, the size of the opposite ends of the second welding mark area is W4, and the size of the opposite ends of the third welding mark area is W5; wherein L4, L5, W4, and W5 satisfy L5<L4 and W5<W4.

9. The cell according to claim 1, wherein The connecting piece is a single-layer structure, and at least one hollow area is arranged on the connecting piece at a position corresponding to the bending part.

10. An electrical device, characterized by The electric device comprises the single battery of any one of claims 1-9.

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