Battery unit and battery module
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Utility models
- Current Assignee / Owner
- CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED
- Filing Date
- 2020-04-17
- Publication Date
- 2026-07-02
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
CROSS-REFERENCE TO RELATED REGISTRATION The present application claims priority from Chinese application no. 201910437844.5, which was filed on May 24, 2019. The disclosed content of the Chinese application is hereby incorporated in its entirety into the present disclosure. AREA OF REVELATION The present disclosure relates to the technical field of batteries, in particular to a battery unit and a battery module. BACKGROUND OF THE REVELATION In recent years, rechargeable batteries have been widely used to power high-performance devices such as electric vehicles. Rechargeable batteries achieve higher capacity or power output by connecting multiple battery units in series or parallel. The existing battery unit is provided with an electrode assembly in the housing. The electrode assembly is formed by layering and winding a positive electrode, a separator, and a negative electrode. Both the positive electrode and the negative electrode comprise a coated section and an uncoated section. The uncoated section forms a tab. The tabs on both sides of the electrode assembly are each connected to positive and negative terminals on the top of the housing by means of current collectors. In the related prior art known to the inventors, the current collectors on both sides of the electrode assembly are provided with support plates to facilitate welding. These support plates are connected to the tabs, and the unit is bent after the tabs have been welded to the support plates. However, this type of connection of the current collectors to the tabs on both sides of the electrode assembly requires more space, and with a constant volume of the battery unit, the winding space is reduced, thus lowering the energy density of the battery. SUMMARY OF THE REVELATION The present disclosure provides a battery unit and an unclaimed manufacturing method for the same, as well as a battery module, with which the energy density of a battery can be effectively improved. According to one aspect of the present disclosure, a battery unit is provided comprising: an electrode assembly comprising a main body part, a negative tab and a positive tab, wherein the negative tab and the positive tab each extend outwards from both ends of the main body part along a longitudinal direction of the electrode assembly; a negative terminal and a positive terminal arranged on the top of the electrode assembly; and a first current collector and a second current collector, wherein the first current collector electrically connects the negative tab to the negative terminal and the second current collector electrically connects the positive tab to the positive terminal;and wherein the first current collector includes a first guide plate, the first guide plate has a flat plate structure, the first guide plate is arranged on one side of the main body part adjacent to the negative terminal along the longitudinal direction and extends along a width direction of the electrode assembly, and the negative tab is bent away from the main body part to one side of the first guide plate and is connected to the first guide plate. In some embodiments, the battery unit comprises two electrode assemblies, wherein the negative tab of one electrode assembly extends from one side of the main body part away from the other electrode assembly along the width direction, and the negative tabs of the two electrode assemblies are bent towards each other along the width direction. In some embodiments, the second current collector includes a second guide plate, the second guide plate has a flat plate structure, the second guide plate is located on one side of the main body part next to the positive terminal along the longitudinal direction and extends along the width direction, and the positive tab is bent to one side of the second guide plate away from the main body part and is connected to the second guide plate. In some embodiments, the second current collector comprises a second guide plate and a support plate, wherein the second guide plate is arranged on one side of the main body part adjacent to the positive terminal along the longitudinal direction and extends along the width direction, the support plate is connected to one end of the second guide plate along the width direction, and the positive tab is connected to the support plate from the outside and is bent completely to one side of the second guide plate away from the main body part. In some embodiments, support plates are arranged at both ends of the second guide plate along the width direction, and the two support plates are bent towards each other. In some embodiments, the support plate is offset inwards by a predetermined distance with respect to the edge of the end of the second guide plate along the width direction; and / or the edge of a free end of at least one of the first guide plates and the second guide plate is offset inwards by a predetermined distance on at least one partial height to form a first recess, and the negative tab or the positive tab passes through the first recess. In some embodiments, the second current collector further comprises a second adapter plate, the positive terminal is attached to the second adapter plate, a side of the support plate adjacent to the second adapter plate and the second adapter plate are spaced apart, and a second recess is formed at one end of a connecting section of the second guide plate and the support plate adjacent to the second adapter plate. In some embodiments, both the negative tab and the positive tab are made of layered structures; and the negative tab comprises a first connecting section and a first collecting section, wherein the first connecting section is arranged on one side of the first guide plate along the longitudinal direction away from the main body part and is connected to the first guide plate, the first collecting section is arranged on one side of the first guide plate along the longitudinal direction next to the main body part and the first guide plate is attached to the first collecting section; wherein the first guide plate contains a substrate layer and the substrate layer is attached to the first collecting section;or the first guide plate contains a substrate layer and an insulating layer, the insulating layer being attached to one side of the substrate layer next to the first collecting section, and the insulating layer being attached to the first collecting section. In some embodiments, each layer of the first connection section is integrally formed by ultrasonic welding and forms a first weld area; the first connection section and the first guide plate are attached by laser welding and form a second weld area; in a plane perpendicular to the longitudinal direction, the projection of the second weld area lies completely within a projection area of the first weld area. In some embodiments, the hardness of the first current collector is greater than the hardness of the second current collector. According to another aspect of the present disclosure, a battery module is provided comprising: a mounting frame; and a plurality of battery units in the above embodiments arranged in the mounting frame and arranged side by side along the width direction. According to a further aspect of the present disclosure, an unclaimed manufacturing method for the battery unit based on the above embodiment is provided, comprising: preparing the electrode unit; attaching the negative terminal to the first current collector and the positive terminal to the second current collector; bending the negative tab and connecting it to the first guide plate; and bending the positive tab and connecting it to the second current collector. In some embodiments, the step of bending the negative tab and joining it to the first guide plate comprises: forming each piece of the negative tabs into a whole by ultrasonic welding; bending the welded negative tab to one side of the first guide plate away from the main body part and attaching the negative tabs to the first guide plate; and performing laser welding on the negative tab and the first guide plate from the outside of the negative tab; or the step of bending the negative tab and joining it to the first guide plate comprises: attaching one side of the main body part perpendicular to the width direction and parallel to the first guide plate and attaching an inside of the negative tab to an outside of the first guide plate; attaching a support element to the inside of the first guide plate;Performing ultrasonic welding on the negative tab and the first guide plate from the outside of the negative tab; and rotating the main body part 90° around the base of the negative tab to bend the negative tab after welding. In some embodiments, the second current collector comprises a second guide plate and a support plate, the support plate being connected to the end of the second guide plate along the width direction, and the step of bending the positive tab and connecting it to the second current collector comprises: attaching a support element to the inside of the support plate; performing ultrasonic welding on the positive tab and the support plate from the outside of the positive tab; and bending the entire welded positive tab and the support plate to one side of the second guide plate away from the main body part. In some embodiments, the negative tab and the first guide plate are ultrasonically welded, and the welding step of the negative tab is performed before the welding step of the positive tab.In some embodiments, the second current collector comprises a second guide plate, the positive tab has a flat plate structure, and the positive tab is bent away from the main body part to one side of the second guide plate and is firmly connected to the second guide plate; laser welding is performed between the negative tab and the first guide plate and between the positive tab and the second guide plate; or laser welding is performed at one of the locations between the negative tab and the first guide plate and between the positive tab and the second guide plate, ultrasonic welding is performed at the other location, and ultrasonic welding is performed before laser welding. According to the above technical solutions, in the battery unit of some embodiments of the present disclosure, the first guide plate of the first current collector has a flat plate structure, and the negative tab is connected to the first guide plate after bending, so that the space occupied by a connecting section of the negative tab and the first current collector on one side of the main body part along the longitudinal direction can be reduced, the winding space can be increased, and the energy density of the battery unit can be improved;Furthermore, the lower-hardness negative tab is individually folded back and connected to the first guide plate, thus reducing the external force exerted on the negative tab in a bending process, reducing the deformation of the first guide plate, ensuring the electrochemical performance and safety performance of the battery unit, and allowing the electrode assembly to be smoothly assembled in a housing. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The drawings shown herein serve to further understand the present disclosure and are part of the present application, and the illustrative embodiments of the present disclosure and their descriptions serve to explain the present disclosure and do not constitute an unreasonable limitation of the present disclosure. In the drawings: Fig. 1 is a schematic representation of the internal structure of some embodiments of a battery unit of the present disclosure; Fig. 2 is a schematic structure diagram of some embodiments of an upper cover assembly in the battery unit of the present disclosure; Fig. 3 is a front view of some embodiments of the battery unit of the present disclosure; Fig. 4 is a sectional view AA of Fig. 3; Figs. 5A and 5B are enlarged views of location B and location C, respectively, in Fig. 4; Fig.Figure 6 is a schematic representation of a welding area for welding a tab in the battery unit of the present disclosure; Figure 7 is a schematic flowchart of some embodiments of an unclaimed manufacturing process for the battery unit of the present disclosure; Figure 8 is a schematic flowchart of other embodiments of the manufacturing process of the battery unit of the present disclosure; Figure 9 is a schematic flowchart of other embodiments of the manufacturing process of the battery unit of the present disclosure; Figure 10 is a schematic flowchart of other embodiments of the manufacturing process of the battery unit of the present disclosure; Figure 11 is a structural diagram of some embodiments of the second current collector in the battery unit of the present disclosure; FigureFigure 12 is a structural diagram of the connection of the first current collector and the negative tab in the battery unit of the present disclosure; Figures 13A and 13B are each structural diagrams of some embodiments of the second current collector and the first current collector in the battery unit of the present disclosure. Reference symbol: 1, Electrode assembly; 11, Main body part; 12, Negative tab; 121, First connecting section; 122, First collecting section; 13, Positive tab; 131, Second connecting section; 132, Second collecting section; 2, First current collector; 21, First guide plate; 211, Substrate layer; 212, Insulating layer; 213, First recess; 3, Second collector; 31, Second guide plate; 311, Second recess; 32, Support plate; 33, Second adapter plate; 4, Negative terminal; 5, Positive terminal; 6, Cover plate; 61, Outlet element; 62, Liquid injection port; 7, Insulating plate; 8, Protective film. DETAILED DESCRIPTION OF PREFERRED EXECUTION FORMS The present disclosure is described in detail below. Various aspects of the embodiments are explained in more detail in the following sections. The aspects thus defined can be combined with any other aspect or aspects unless it is clearly indicated that they are not combinable. In particular, any feature considered preferred or advantageous can be combined with one or more other features considered preferred or advantageous. The terms “first”, “second” and the like, which appear in the present revelation, serve only for the simpler description in order to distinguish different components with the same name, and do not indicate a sequential or primary and secondary relationship. When an element is described as "standing on" another element, it can either stand directly on top of the other element or stand indirectly on top of it with one or more intermediate elements inserted between them. When an element is described as "connected" to another element, it can stand directly on top of it or stand indirectly on top of it with one or more intermediate elements inserted between them. The same reference sign refers to the same element in subsequent references. To clearly describe different orientations in the following embodiments, various directions of a battery unit are defined in a coordinate system in Fig. 1, where an x-direction represents the longitudinal direction of the battery unit; a y-direction is perpendicular to the x-direction in the horizontal plane and represents the width direction of the battery unit; a z-direction is perpendicular to a plane formed by the x- and y-directions and represents the height direction of the battery unit. The direction definition of the electrode assembly 1 is the same as that of the battery unit.Based on this definition of orientation, the description of the orientation or positional relationships by "top", "bottom", "front", "back", "inside" and "outside" merely serves to simplify the description of the present disclosure and does not mean that the device in question must have a particular orientation or be designed and operated in a particular orientation, and is therefore not to be understood as a limitation of the scope of protection of the present disclosure. In order for the person skilled in the art to better understand the improvements of the present disclosure, the overall structure of the battery module and the battery unit will first be described. If the battery module is formed by a plurality of battery units, the battery module comprises a mounting frame and a plurality of battery units. The battery units are arranged in the mounting frame, side by side along the width direction, and can be connected at least in parallel or in series. Each battery unit can be separately enclosed in a casing, or the casing can be omitted. The battery units can also be used individually. Fig. 1 schematically shows a structural diagram of some embodiments of a battery unit of the present disclosure. The battery unit can comprise an electrode assembly 1, a cover plate 6, two terminals, and two current collectors. When the battery unit is used alone, a housing connected to the cover plate 6 and filled with electrolyte is also arranged on the outside of the electrode assembly 1. There is either only one electrode assembly 1 in the lateral direction of the battery unit, or a plurality of electrode assemblies 1 are arranged one above the other, and the electrode assembly 1 comprises a main body part 11, a negative tab 12, and a positive tab 13, the negative tab 12 and the positive tab 13 each extending from both ends of the main body part 11 along the longitudinal direction. Specifically, the main body part 11 is a coated part containing a first electrode and a second electrode with opposite polarities; for example, the first electrode is a positive electrode and the second electrode is a negative electrode. The negative tab 12 and the positive tab 13 are uncoated parts; both the negative tab 12 and the positive tab 13 are made of aluminum and are layered structures. The battery unit contains only a single electrode assembly 1, which is suitable for situations where the lamination thickness of the electrode layers is relatively small. Alternatively, as shown in Fig. 1, if the lamination thickness of the electrode layers is relatively large, two or more independently wound electrode assemblies 1 can be arranged in the battery unit, with all tabs of the electrode assemblies 1 extending from both sides of the current collector along the width direction. The cover plate 6 is arranged on the top side of the electrode assembly 1 and is provided with an outlet element 61 and a liquid injection port 62. The outlet element 61 is used to release a gas into the battery unit to achieve a safety function, and the liquid injection port is used to inject electrolyte into the battery unit and is sealed by a sealing element. The two terminals are arranged longitudinally at both ends of the top side of the cover plate 6 and comprise a negative terminal 4 and a positive terminal 5. An insulating plate 7 is arranged on the underside of the cover plate 6 to insulate the cover plate 6 from the electrode assembly 1 and thus improve the insulation performance in the battery unit. The two current collectors comprise a first current collector 2 and a second current collector 3. The first current collector 2 electrically connects the negative tab 12 to the negative terminal 4, and the second current collector 3 electrically connects the positive tab 13 to the positive terminal 5. Based on the overall structure of the battery unit shown above, the improvements of the present disclosure will be explained in more detail below. In some embodiments, as shown in Fig. 1 and Fig. 2, the first current collector 2 comprises a first guide plate 21 and a first adapter plate, wherein the first adapter plate is connected to an upper end of the first guide plate 21, so that the first current collector 2 integrally forms an L-shaped structure, and the negative terminal 4 is attached to the first adapter plate.The first guide plate 21 has a flat plate structure. It is located on one side of the main body part 11 next to the negative terminal 4 along the longitudinal direction and extends along the width direction. The negative tab 12 is bent away from the main body part 11 to one side of the first guide plate 21. An outer side surface of the first guide plate 21 is in contact with a folded-back section of the negative tab 12, and the negative tab 12 is connected to the first guide plate 21, for example, by welding. To prevent damage to the tabs during welding, a protective film 8 can be applied to the outer surface of the outermost tab. In the embodiment of the present disclosure, the first current collector 2 has a flat plate structure, and the negative tab 12 is connected to the first guide plate 21 after bending. This reduces the space occupied by the connecting section of the negative tab 12 and the first current collector 2 on one side of the main body part 11 along the longitudinal direction, thereby increasing the winding space and effectively improving the energy density and performance of the battery unit. Alternatively, the overall size of the battery unit can be reduced if the size of the electrode assembly 1 remains constant. If several flat plates are cut and bent from a single plate to form the first current collector 2, the plate utilization rate can be improved and costs reduced. Since the first current collector 2 is generally made of the same material as the negative terminal 4, such as...In the copper-based structure, its material hardness is relatively high compared to the prior art structure in which support plates are arranged at both ends of the first guide plate of the current collector with negative electrode along the width direction. When the negative tabs on both sides are bent together with the support plates, if the first guide plate is deformed concavely towards the main body part, pressure is transferred to at least part of the electrodes in the main body part. This causes slight demolding or powder shedding of the active substance-coated electrodes due to mechanical force, thereby impairing the electrochemical performance and safety of the battery unit. Furthermore, if the first guide plate is deformed convexly away from the main body part, the assembly of the battery unit is impaired. In the embodiment of the present disclosure, when bending the negative tab 12, the negative tab 12 with lower hardness is directly folded back and connected to the first guide plate 21, and the bending of the support plate is not involved, so that the external force to be applied during the bending process can be reduced, the deformation of the first guide plate 21 of the first current collector 2 is reduced, the electrochemical performance and the safety performance of the battery unit are ensured, furthermore the first guide plate 21 is prevented from protruding outwards, and the electrode assembly can be smoothly installed in the housing. As shown in Fig. 1, the battery unit comprises two electrode assemblies 1, wherein the negative tab 12 of one electrode assembly 1 is led away from the other electrode assembly 1 from one side of the main body part 11 along the width direction and the negative tabs 12 of the two electrode assemblies 1 are bent towards each other along the width direction. If the winding thickness of the electrode assembly 1 is relatively large, the size of the circular arc at the base is also relatively large, resulting in a low space utilization rate for the electrode assembly 1 on the outer sides of the circular arcs on both sides of the base. Dividing the electrode assembly into two electrode assemblies 1 reduces the size of the circular arc, fully utilizes the base space of the battery unit, reduces wasted space, and increases the energy density of the battery core. Furthermore, the overall thickness of the tabs is reduced, which also facilitates welding and bending, and the length of a single tab can be decreased. Additionally, the risk of the innermost tab being inserted into the main body part 11 due to the long path it takes can also be reduced. In some embodiments, as shown in Fig. 11, the second current collector 3 comprises a second guide plate 31 and a second adapter plate 33. The second adapter plate 33 is connected to the upper end of the second guide plate 31 to form an L-shaped structure, and the positive terminal 5 is attached to the second adapter plate 33. The second guide plate 31 also has a plate structure. The second guide plate 31 is located on one side of the main body part 11 next to the positive terminal 5 along the longitudinal direction and extends along the width direction. The positive tab 13 is bent away from the main body part 11 on one side of the second guide plate 31 and is connected to the second guide plate 31, for example, by welding. In the embodiment of the present disclosure, the second current collector 3 is also of the flat plate structure, so that the space occupied by the connecting section of the positive tab 13 and the second current collector 3 on the other side of the main body part 11 along the longitudinal direction can be reduced, and the reduced thickness is the thickness of the support plate. By designing both the first current collector 2 and the second current collector 3 as flat plate structures, the winding space can be further increased, thereby effectively improving the energy density of the battery unit. Furthermore, the second current collector 3 is usually made of the same material as the positive terminal 5, such as aluminum, although the material hardness is relatively low, so that slight deformation may occur when bending the positive tabs on both sides together with the support plate; or the second current collector 3 can also be made of a material with higher hardness.In the present embodiments, when the positive tab 13 is bent, the positive tab 13 can be folded back individually without having to bend the support plate, thus reducing the requirements for the hardness of the material of the second current collector 3, reducing the deformation of the second guide plate 31 of the second current collector 3, ensuring the continued electrochemical performance and safety performance of the battery unit, preventing the second guide plate 31 from protruding outwards, and allowing the electrode assembly 1 to be smoothly mounted in the casing. Furthermore, the first current collector 2 and the second current collector 3 adopt the same structure, and the same procedure can be used for bending the tab and attaching it to the guide plate. For example, if the tab and the guide plate are attached by welding, the same procedure can be used, thus simplifying the process flow and reducing the manufacturing difficulties of the battery unit. In some other embodiments, where the hardness of the second current collector 3 is lower than the hardness of the first current collector 2, as shown in Fig. 2 and Fig. 11, the second current collector 3 comprises a second guide plate 31, a second adapter plate and a support plate 32, wherein the second guide plate 31 is arranged on one side of the main body part 11 adjacent to the positive terminal 5 along the longitudinal direction and extends along the width direction, the support plate 32 is connected to the end of the second guide plate 31 along the width direction and the positive tab 13 is connected to the support plate 32 from the outside and is bent completely to one side of the second guide plate 31 away from the main body part 11.After the positive tab 13 is folded back, the positive tab 13 covers the support plate 32 in the width direction, and the two ends of the support plate 32 in the height direction can extend beyond the positive tab 13 or be flush with it. The second guide plate 31, the second adapter plate 33 and the support plate 32 are formed in one piece, and this structure can reduce processing difficulties and improve structural strength. Since the hardness of the material of the second current collector 3 is relatively low, the deformation when bending the positive tab 13 together with the support plate 32 is relatively small, and the impact on the electrochemical performance, safety performance, and assembly of the battery unit is also relatively small. Therefore, the second current collector 3 with the support plate 32 continues to be used. The advantage of this structure is that a support element can be easily arranged on the inside of the support plate 32, and the support plate 32 and the positive tabs 13 can be ultrasonically welded by applying a pre-pressure before bending, thus improving the strength of the connection between the support plate 32 and the positive tabs 13. As shown in Fig. 3 and the sectional view AA in Fig. 4, support plates 32 are arranged at both ends of the second guide plate 31 in the lateral direction, and the two support plates 32 are bent towards each other. With this structure, the positive tabs 13 on both sides along the lateral direction and the second current collector 3 can employ the same joining and bending procedures, thus simplifying the process flow and reducing the manufacturing difficulties of the battery unit. As shown in Fig. 2, the support plate 32 can be arranged so that, in an unfolded state, it forms an enclosed angle with the second guide plate 31, for example, an angle of 90°, and the positive tabs 13, corresponding to two electrode assemblies 1, are attached to the outer sides of the support plate 32. The positive tabs 13 and the support plates 32 must first be firmly connected to each other by welding or other means and are then fully folded back so that the support plates 32 are joined with the second guide plate 31. When bending the positive tabs 13 on both sides together with the support plates 32, forces must first be applied to the outer sides of the support plates 32 via rollers to gradually bend them back.After the support plates 32 have been essentially bent back into place, one side of the second guide plate 31, which faces away from the main body part 11 of the electrode assembly, is placed upwards, and the positive tabs 13 on both sides are flattened by a flat plate tool, and the flat plate tool covers the area corresponding to the two positive tabs 13. Fig. 3 is a front view of the battery unit shown in Fig. 1, and Fig. 4 is a sectional view of Fig. 3, showing a schematic structural diagram after the flap has been folded back. The battery unit comprises two electrode assemblies 1, and the tabs of the two electrode assemblies 1 extend as a whole from both sides of the two main body parts 11 along the width direction. The first guide plate 21 of the first current collector 2 adopts a flat plate structure and has no support plate. The negative tabs 12 on both sides are bent away from the main body part 11 on one side of the first guide plate 21 and are bent towards each other, and the negative tabs 12 are connected to the first guide plate 21.The support plates 32 are arranged at the two ends of the second guide plate 31 of the second current collector 3 along the width direction, the positive tabs 13 on both sides are connected to the corresponding support plates 32 from the outside, and the positive tabs 13 on both sides are bent away from the main body part 11 and towards each other on one side of the first guide plate 21. The tabs on the same side of the main body part 11 along the longitudinal direction have no overlapping portion in the lateral direction after being folded back, and the ends of the two tabs may touch each other or have a gap after being folded back. This structure allows the tabs on both sides of the main body part 11 to be independent of each other along the lateral direction, and the space occupied by the connecting section of the tab and the current collector in the longitudinal direction can be further reduced to increase the winding space and improve the energy density of the battery. In some embodiments, one end of the second guide plate 31 is provided with the support plate 32 along the width direction, the positive tab 13 on the side provided with the support plate 32 is attached to the outside of the support plate 32, and the positive tab 13 and the support plate 32 are completely folded back after being joined together by welding or otherwise, so that the support plate 32 is attached to the second guide plate 31; the positive tab 13 on the side without the support plate 32 is bent directly to one side of the second guide plate 31 away from the main body part 11 and is connected to the second guide plate 31.This structure allows the partial space occupied in the longitudinal direction by the connecting structure of the positive tab 13 and the second current collector 3 to be reduced, and the electrode assembly 1 can be defined as a partially protruding structure along the longitudinal direction to further improve the energy density of the battery unit. As shown in Fig. 13A, if the tab is relatively thick and the second current collector 3 includes the support plate 32, the projection of the support plate 32 is offset inwards by a predetermined distance relative to the edge of the end part of the second guide plate 31 along the width direction. This structure is suitable for battery units with one or more electrode assemblies 1. In the present embodiments, if the lamination thickness of the positive tabs 13 is relatively large, the positive tabs 13 can be easily bent, and the cover length, where the positive tabs 13 circumvent the support plates 32, can be reduced, thereby reducing the overall length of the positive tabs 13 and saving material. Furthermore, the positive tabs 13 can be attached to the support plates 32, further reducing the size of the battery unit in the longitudinal direction. As shown in Fig. 13B, if the tab is relatively thick, with respect to the end of the first guide plate 21 and the second guide plate 31, which is not provided with a support plate 32, the edge of a free end of at least one of the first guide plate 21 and the second guide plate 31 is offset inwards along the width direction by a predetermined distance over at least one partial height to form a first recess 213, and the negative tab 12 or the positive tab 13 passes through the first recess 213. The first recess 213 can, for example, be rectangular. In the present embodiments, when the lamination thickness of the tab layers is relatively large, the tabs can be easily bent, and the cover length, where the tabs circumvent the guide plates, can be reduced. The tab ends do not need to be bent to form a circular arc structure; instead, an obliquely shaped structure is formed, thus reducing the overall length of the tabs and saving material. Furthermore, it is advantageous to connect the tabs to the guide plate, thereby further reducing the size of the battery unit in the longitudinal direction. As shown in Fig. 2, the second current collector 3 further comprises a second adapter plate 33. The positive terminal 5 is attached to the second adapter plate 33. The top of the support plate 32 and the second adapter plate 33 are spaced apart. A second recess 311 is formed at one end of a connecting section between the second guide plate 31 and the support plate 32. This second recess 311 allows the positive tab 13 and the support plate 32 to be easily folded back after welding, thus preventing stress concentration on the bent part in the folded-back state and avoiding cracking. The second recess 311 could, for example, be a process hole formed by punching. In some embodiments, shown in an enlarged view of location B as in Fig. 5A, the negative tab 12 has a layered structure. The negative tab 12 comprises a first connecting section 121 and a first collecting section 122. The first connecting section 121 is located on one side of the first guide plate 21 that is away from the main body part 11 along the longitudinal direction and is firmly connected to the first guide plate 21. The first collecting section 122 is located on one side of the first guide plate 21 that is adjacent to the main body part 11 along the longitudinal direction, and the first guide plate 21 is attached to the first collecting section 122. This structure can further reduce the space occupied by the connecting section of the tab and the current collector on the side of the main body part 11 and increase the winding space, thereby effectively improving the energy density of the battery unit. As shown in Fig. 12, the negative tab 12 extends from an intermediate position of the main body part 11 of the individual electrode assembly 1 along the width direction. Since the first guide plate 21 is attached to the first manifold section 122, in order to improve the insulation between the first guide plate 21 and the main body part 11, the first guide plate 21 comprises a substrate layer 211 and an insulating layer 212. The insulating layer 212 is attached to the substrate layer 211 on one side adjacent to the first manifold section 122 and is also attached to the first manifold section 122. The insulating layer 212 can be bonded to the substrate layer, for example, by adhesive bonding. As shown in Fig. 5A, the first guide plate 21 includes a substrate layer 211 to ensure insulation between the first guide plate 21 and the main body part 11, wherein no insulating layer is attached to the substrate layer 211 and the substrate layer 211 is attached directly to the first collecting section 122. In some embodiments, in the enlarged view of location C, as in Fig. 5B, the positive tab 13 of the layered structure includes a second connecting section 131 and a second collecting section 132. The second connecting section 131 is arranged on one side of the second guide plate 31 away from the main body part 11 along the longitudinal direction and is firmly connected to the support plate 32. The second collecting section 132 is arranged on one side of the second guide plate 31 adjacent to the main body part 11 along the longitudinal direction, and the second guide plate 31 is attached to the second collecting section 132. To improve the insulation between the second guide plate 31 and the main body part 11, the second guide plate 31 comprises a substrate layer and an insulating layer, the insulating layer being attached to the side of the substrate layer that borders the second collecting section 132 and being fixed to the second collecting section 132. The insulating layer can be bonded to the substrate layer, for example, by adhesive bonding. The substrate layer and the insulating layer of the second guide plate 31 can have a structure similar to that shown in Fig. 12. To ensure insulation between the second guide plate 31 and the main body part 11, the second guide plate 31 can contain a substrate layer, with no insulating layer attached to the substrate layer and the substrate layer being attached directly to the second collecting section 132. In practice, gaps may exist between the inner surface of the first guide plate 21 and the first collecting section 122, and between the inner surface of the second guide plate 31 and the second collecting section 132. However, after the tabs have been bent into place, the outer surfaces of the tabs on both sides of the main body part 11 are clamped along the longitudinal direction using tools. This ensures that both sides of the first guide plate 21 are attached to the negative tab 12 and the first collecting section 122, and both sides of the second guide plate 31 are attached to the positive tab 13 and the second collecting section 132. Simultaneously, the support plate 32 is also in contact with the second guide plate 31 under the influence of a compressive force. The support plate 32 can be fully attached to the second guide plate 31, or its free end can be attached to the second guide plate 31. For the structure that is connected to the guide plate by individually bending the tab, if laser welding is performed directly on each layer of the tabs and the guide plate after folding back, because pressure cannot be applied, the tab layers are difficult to press, resulting in hollow welding, and also, impurities are easily generated during the laser welding process; furthermore, after folding back the tab layers, the support element cannot be provided, and then ultrasonic welding cannot be used. For this reason, the welding mode used in the present disclosure is as follows: First, the support element is arranged on the inside of the tab, and the tab layers are welded together by ultrasound; second, the tab formed into a whole is bent away from the main body part 11 to one side of the guide plate; and third, the tab is firmly connected to the guide plate by laser welding. In the present embodiments, ultrasonic welding is first used to apply pressure and compress the tab layers, thus preventing hollow welding and improving the strength of the tab layers after welding. After the tabs have been bent, laser welding is performed between the tabs and the guide plate to overcome the problem of not being able to position the support element. Since the tabs are formed entirely by welding, the reliability of the weld is ensured and the formation of impurities is reduced. This type of welding combines the advantages of ultrasonic and laser welding. In some embodiments, as shown in Fig. 6, the projection of a second weld area W2, formed by laser welding, lies entirely within the projection area of a first weld area W1, formed by ultrasonic welding, in a plane perpendicular to the longitudinal direction. The weld area can have a rectangular or rectangular annular structure, or a circular, triangular, or other polygonal structure. This structure largely prevents the formation of rosin deposits and reduces impurities generated during laser welding. Furthermore, it is advantageous that the first weld area W1 is located entirely outside the bending area of the tab, thus facilitating tab bending. In the case of the negative tab 12, as shown in Fig. 6, each layer of the first connecting section 121 is integrally formed by ultrasonic welding and forms the first weld area W1. The first connecting section 121 and the first guide plate 21 are joined by laser welding and form the second weld area W2, and the first weld area W1 completely covers the second weld area W2. In the case of the positive tab 13, each layer of the second connecting section 131 is integrally formed by ultrasonic welding and forms the first weld area W1. The second connecting section 131 and the second guide plate 31 are joined by laser welding and form the second weld area W2, and in the plane perpendicular to the longitudinal direction, the projection of the second weld area W2 lies completely within the projection area of the first weld area W1. Furthermore, the present disclosure provides an unclaimed manufacturing method for the battery unit based on the embodiments mentioned above. In some embodiments, as shown in the schematic flowchart in Fig. 7, the manufacturing method comprises: Step 101: Preparing the electrode assembly 1; Step 102: Attaching the negative terminal 4 and the positive terminal 5 to the first current collector 2 and the second current collector 3, respectively; Step 103: Bending the negative tab 12 and connecting it to the first guide plate 21, e.g., by welding or the like; and Step 104: Bending the positive tab 13 and connecting it to the second current collector 3, e.g., by welding or the like. Steps 101 and 102 are performed sequentially, steps 103 and 104 are performed after step 102, and the order in which steps 103 and 104 are performed is not limited. In the embodiments of the present disclosure, when bending the negative tab 12, the negative tab 12 with lower hardness is directly folded back and connected to the first guide plate 21, and the bending of the support plate is not involved, so that the external force to be applied during the bending process can be reduced, the deformation of the first guide plate 21 of the first current collector 2 is reduced, the electrochemical performance and the safety performance of the battery unit are ensured, furthermore the first guide plate 21 is prevented from protruding outwards, and the electrode assembly can be smoothly installed in the housing. In some embodiments, as shown in the schematic flowchart in Fig. 8, step 103 of bending the negative tab 12 and joining it to the first guide plate 21 comprises in particular: step 201, wherein each piece of the negative tabs 12 is pre-assembled by ultrasonic welding on partial areas of the negative tabs 12 to form the first weld area W1, wherein during welding the support element can be placed on the inner sides of the negative tabs 12 to exert pressure during ultrasonic welding; step 202, then bending the welded negative tab 12 to one side of the first guide plate 21 away from the main body part 11 and attaching the negative tab 12 to the first guide plate 21;and step 203, performing laser welding on the negative tab 12 and the first guide plate 21 from the outside of the negative tab 12 to form a second welding area W2, wherein, for example, the first welding area W1 completely covers the second welding area W2. Steps 201 to 203 are performed sequentially. In the present embodiments, ultrasonic welding is first used to apply pressure to compress the tab layers, thus preventing hollow welding and improving the strength of the tab layers after welding. After the tabs have been bent, laser welding is performed between the tabs and the guide plate to solve the problem of not being able to position the support element. Furthermore, since the tabs are welded as a whole, post-weld reliability can be ensured, the generation of contaminants can be reduced, and the weld quality is optimized. In some other embodiments, as shown in the schematic flowchart in Fig. 9, step 103 of bending the negative tab 12 and joining it to the first guide plate 21 comprises, in particular: step 301, attaching a side of the main body part 11 perpendicular to the width direction and parallel to the first guide plate 21, and attaching an inside of the negative tab 12 to an outside of the first guide plate 21, the first guide plate 21 being, for example, in a vertical state; step 302, attaching a support element to the inside of the first guide plate 21, e.g., a padding block or the like; step 303, performing ultrasonic welding on the negative tab 12 and the first guide plate 21 from the outside of the negative tab 12; and step 304, after welding, rotate the main body part 11 by 90° around the base of the negative tab 12 to bend the negative tab 12. Steps 301 to 304 are performed sequentially. During the welding process in step 303, a supporting restraint of the main body part 11 can be applied to prevent the main body part 11 from shifting and impairing the welding effect. In the present embodiment, the negative tab 12 and the first guide plate 21 can be directly ultrasonically welded. The negative tab 12 is bent by rotating the main body part 11. The weld strength can be improved by applying pressure, thus preventing hollow welding and reducing the formation of impurities. In Fig. 2, all tabs are ultrasonically welded, reducing the requirements for the type of welding equipment, simplifying the process flow, and improving welding efficiency. In some embodiments, as shown in Fig. 2, the second current collector 3 comprises a second guide plate 31 and a support plate 32, and the support plate 32 is connected to the end of the second guide plate 31 along the width direction. As shown in the schematic flow diagram in Fig. 10, step 104 of bending the positive tab 13 and connecting it to the second current collector 3 includes, in particular: step 401: attaching a support element to the inside of the support plate 32 to generate a support force for ultrasonic welding; step 402: performing ultrasonic welding on the positive tab 13 and the support plate 32 from the outside of the positive tab 13; and step 403: bending the entire welded positive tab 13 and the support plate 32 to one side of the second guide plate 31 away from the main body part 11. Steps 401 to 403 are carried out sequentially. The present embodiment is suitable for welding the positive tab 13 provided with the support plate 32. The support plate 32 and the second guide plate 31 form an L-shaped structure. Before bending, a space is created for placing the support element, making it suitable for ultrasonic welding. Applying pressure improves weld strength, prevents hollow welding, and reduces the generation of impurities. In the structure shown in Fig. 2, when the negative tab 12 and the first guide plate 21 are ultrasonically welded, the positive tab 13 and the support plate 32 are also ultrasonically welded, since the rotation of the main body part 11 is involved in the ultrasonic welding process of the negative tab 12 and the first guide plate 21, the ultrasonic welding process of the negative tab 12 should be carried out before the welding step of the positive tab 13. If the layers of the negative tab 12 are integrally formed by ultrasonic welding and then bent and laser-welded to the first guide plate 21, and the positive tab 13 and the support plate 32 are also ultrasonically welded, then the welding sequence of the negative tab 12 and the positive tab 13 is not limited. In the present application, by adopting a direct welding structure of the tab and the guide plate, the welding flexibility of the tabs can be improved, and the main body part 11 does not need to be rotated during the welding process, thus reducing operational difficulties. In some other embodiments, the second current collector 3 includes a second guide plate 31, the positive tab 13 has a flat plate structure, the positive tab 13 is bent to one side of the second guide plate 31 away from the main body part 11 and is firmly connected to the second guide plate 31, i.e. neither the first collector 2 nor the second collector 3 is provided with the support plate. There are two welding modes for this structure: First, laser welding is carried out between the negative tab 12 and the first guide plate 21 and between the positive tab 13 and the second guide plate 31, and the negative tabs 12 or positive tabs 13 must be welded together to form a whole before laser welding. Secondly, laser welding is performed at one of the points between the negative tab 12 and the first guide plate 21 and between the positive tab 13 and the second guide plate 31, while ultrasonic welding is performed at the other point. Since ultrasonic welding requires rotation of the main body part 11, it is performed before laser welding. The battery unit, its manufacturing process, and the battery module provided by the present disclosure are described in detail above. The principles and embodiments of the present disclosure have been described here with reference to specific embodiments, and the description of the embodiments above serves only to facilitate understanding of the method of the present disclosure and its core idea. It should be noted that the person skilled in the art may make various improvements and modifications to the present disclosure without departing from the principles of the present disclosure, and that these improvements and modifications also fall within the scope of protection of the claims of the present disclosure. QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature CN 201910437844.5
[0001]
Claims
A battery unit comprising: an electrode assembly (1) comprising a main body part (11), a negative tab (12) and a positive tab (13), wherein the negative tab (12) and the positive tab (13) each extend outwards from both ends of the main body part (11) along a longitudinal direction of the electrode assembly (1); a negative terminal (4) and a positive terminal (5) arranged on the top of the electrode assembly (1); and a first current collector (2) and a second current collector (3), wherein the first current collector (2) electrically connects the negative tab (12) to the negative terminal (4) and the second current collector (3) electrically connects the positive tab (13) to the positive terminal (5); and wherein the first current collector (2) comprises a first guide plate (21), the first guide plate (21) having a flat plate structure.The first guide plate (21) is arranged on one side of the main body part (11) adjacent to the negative terminal (4) along the longitudinal direction and extends along a lateral direction of the electrode assembly (1), and the negative tab (12) is bent separately to one side of the first guide plate (21) away from the main body part (11) and is connected to the first guide plate (21), wherein each layer of the negative tab (12) is integrally welded by ultrasonic welding and forms a first weld area (W1), the negative tab (12) and the first guide plate (21) are fixed by laser welding and form a second weld area (W2), wherein in a plane perpendicular to the longitudinal direction the projection of the second weld area (W2) is completely arranged within a projection area of the first weld area (W1). The battery unit according to claim 1, comprising two electrode assemblies (1), wherein the negative tab (12) of one electrode assembly (1) extends from one side of the main body part (11) away from the other electrode assembly (1) along the width direction and the negative tabs (12) of the two electrode assemblies (1) are bent towards each other along the width direction. The battery unit according to claim 1 or 2, wherein the second current collector (3) comprises a second guide plate (31), the second guide plate (31) has a flat plate structure, the second guide plate (31) is arranged on one side of the main body part (11) adjacent to the positive terminal (5) along the longitudinal direction and extends along the width direction, and the positive tab (13) is bent to one side of the second guide plate (31) away from the main body part (11) and is connected to the second guide plate (31). The battery unit according to claim 1 or 2, wherein the second current collector (3) comprises a second guide plate (31) and a support plate (32), wherein the second guide plate (31) is arranged on one side of the main body part (11) adjacent to the positive terminal (5) along the longitudinal direction and extends along the width direction, the support plate (32) is connected to one end of the second guide plate (31) along the width direction, and the positive tab (13) is connected to the support plate (32) from the outside and is bent completely to one side of the second guide plate (31) away from the main body part (11). The battery unit according to claim 4, wherein support plates (32) are arranged at the two ends of the second guide plate (31) in the width direction and the two support plates (32) are bent towards each other. The battery unit according to claim 4 or 5, wherein the support plate (32) is offset inwards along the width direction by a predetermined distance with respect to the edge of the end of the second guide plate (31); and / or the edge of a free end of at least one of the first guide plate (21) and the second guide plate (31) is offset inwards along the width direction by a predetermined distance on at least one partial height to form a first recess (213), and the negative tab (12) or the positive tab (13) passes through the first recess (213). The battery unit according to any one of claims 1 to 6, wherein both the negative tab (12) and the positive tab (13) consist of layered structures; and the negative tab (12) comprises a first connecting section (121) and a first collecting section (122), wherein the first connecting section (121) is arranged on one side of the first guide plate (21) remotely from the main body part (11) along the longitudinal direction and is connected to the first guide plate (21), wherein the first collecting section (122) is arranged on one side of the first guide plate (21) adjacent to the main body part (11) along the longitudinal direction, and wherein the first guide plate (21) is attached to the first collecting section (122); wherein the first guide plate (21) comprises a substrate layer (211) and the substrate layer (211) is attached to the first collecting section (122);or the first guide plate (21) comprises a substrate layer (211) and an insulating layer (212), the insulating layer (212) being attached to one side of the substrate layer (211) adjacent to the first collecting section (122) and the insulating layer (212) being attached to the first collecting section (122). The battery unit according to claim 7, wherein each layer of the first connecting section (121) is formed in one piece by ultrasonic welding and forms the first welding area (W1), the first connecting section (121) and the first guide plate (21) are attached by laser welding and form the second welding area (W2). The battery unit according to one of claims 1-8, wherein the hardness of the first current collector (2) is greater than the hardness of the second current collector (3). A battery module comprising: a mounting frame; and a plurality of battery units according to any one of claims 1 to 9, arranged in the mounting frame and arranged side by side along the width direction.