Busbar assembly and cylindrical power battery module

Abstract

A bus bar assembly and a cylindrical power battery module are provided. [Solution] The present application discloses a busbar assembly and a cylindrical power battery module, the busbar assembly is used for circuit connection of the cylindrical power battery module, and includes an input copper bar, an output copper bar and a number of cell contact system assemblies corresponding to the sub-modules, the input copper bar is connected to the cell unit at the input end of the cylindrical power battery module, the output copper bar is connected to the cell unit at the output end of the cylindrical power battery module, and the cell contact system assemblies connect the cell units of the sub-modules in series and in parallel.

Description

[Technical field]

[0001] This disclosure claims priority to Chinese patent application having application number 202210088580.9, filed with the China Patent Office on January 25, 2022, and to Chinese patent application having application number 202220207020.6, filed with the China Patent Office on January 25, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the field of batteries, for example, busbar assemblies and cylindrical power battery modules. [Background technology]

[0003] Most of the large cylindrical power battery modules (e.g., cylindrical batteries with poles on the same side) complete the collection of voltage and temperature signals of the large cylindrical power battery module by connecting a flexible printed circuit (FPC), a negative temperature coefficient thermistor (NTC thermistor), and a battery management system (BMS) through a harness. However, the method of collecting voltage and temperature signals using a harness requires a large number of harnesses, a large amount of space, and a temperature sensor is usually required to be crimped to the harness, which complicates the assembly process of the large cylindrical power battery module, relatively increases labor costs, and is disadvantageous to efficient industrial production. In addition, when the large cylindrical power battery module needs to be fast-charged at a high rate, there is a high requirement for the overcurrent capacity of the busbar in the large cylindrical power battery module. In order to meet the requirement of overcurrent capacity, the busbar in the related art is made thick, which results in a large amount of space being occupied. Summary of the Invention [Problem to be solved by the invention]

[0004] The present application provides a busbar assembly and a cylindrical power battery module to solve the problems in the related art that the busbar occupies a large space in the cylindrical power battery module and the busbar has low reliability in connecting multiple cell units. [Means for solving the problem]

[0005] In a first aspect, an embodiment of the present application provides a busbar assembly for circuit connection of a cylindrical power battery module including at least one sub-module including a plurality of cell units, the busbar assembly comprising: an input copper bar connected to the cell unit at the input end of the cylindrical power battery module; an output copper bar connected to the cell unit at the output end of the cylindrical power battery module; a cell contact system assembly having a number corresponding to the sub-modules; A busbar assembly is provided in which one of the sub-modules is connected to one of the cell contact system assemblies to form an electrical unit set, the cell contact system assembly having at least one connection sheet, the connection sheet having a plurality of conductive units and a plurality of connection portions, the conductive units arranged adjacent to each other and spaced apart along a first direction are connected by the connection portions, the conductive units are parallel to the cell units arranged adjacent to each other along the first direction, and the conductive units are in series with the cell units arranged adjacent to each other along a second direction.

[0006] In one embodiment, the conductive unit is provided with a protrusion forming a first buffer portion.

[0007] In one embodiment, the first buffer portion is provided with a first fusing structure.

[0008] In an embodiment, the conductive unit is provided with a first fusing structure, or the first buffer part of the conductive unit is provided with a first fusing structure.

[0009] In one embodiment, the thickness of the connection sheet is between 0.2 mm and 0.4 mm.

[0010] In one embodiment, the connection sheet comprises a first insulating layer provided on one side of the connection sheet close to the cell unit.

[0011] In one embodiment, the cell unit comprises a positive electrode and a negative electrode, the negative electrode is provided on an end face of the cell unit, the positive electrode is provided on the same side as the negative electrode, the positive electrode has a cylindrical protrusion, and the conductive unit is provided with a first escape groove capable of avoiding the cylindrical protrusion.

[0012] In one embodiment, the connection portion has a planar structure, or the connection portion has a protruding structure and includes a second buffer portion.

[0013] In an embodiment, the connection portion is provided with a second fusing structure, or the second buffer portion is provided with a second fusing structure.

[0014] In one embodiment, the conductive unit includes a first connection region and a second connection region each connected to two of the cell units disposed adjacent to each other along the first direction.

[0015] In one embodiment, the first connection region and the second connection region have different heights in a third direction.

[0016] In one embodiment, the first connection region includes a second insulating layer configured to isolate portions of the first connection region other than those connected to the cell unit, and the second connection region includes a third insulating layer configured to isolate portions of the second connection region other than those connected to the cell unit.

[0017] In one embodiment, at least one of the input copper bar and the output copper bar is a variable cross-section copper bar, and both the input copper bar and the output copper bar have a first end and a second end, the first end of the input copper bar is connected to the cell unit at the input end of the cylindrical power battery module, and the first end of the output copper bar is connected to the cell unit at the output end of the cylindrical power battery module.

[0018] In one embodiment, the thickness of the first end is less than the thickness of the second end, the thickness of the first end being between 0.2 mm and 0.4 mm, and the thickness of the second end being between 3 mm and 5 mm.

[0019] In one embodiment, the first end has a number of input connection portions corresponding to the number of conductive units on the same connection sheet.

[0020] In an embodiment, the first end has a planar structure, or the first end has a protruding structure and includes a third buffer portion.

[0021] In an embodiment, the first end of the output copper bar is provided with a third fusing structure, or the third buffer portion is provided with a third fusing structure.

[0022] In one embodiment, there is one sub-module, the input end of the cylindrical power battery module is the cell unit at the first end of the sub-module, and the output end of the cylindrical power battery module is the cell unit at the second end of the sub-module.

[0023] In one embodiment, the sub-module is multiple, and the cell contact system assembly further includes a connecting copper bar connecting adjacent sub-modules except for the input end of the cylindrical power battery module and the output end of the cylindrical power battery module.

[0024] In one embodiment, the plurality of sub-modules are spaced apart along the first direction, an input end of the cylindrical power battery module is a cell unit at one end of a first sub-module along the first direction, and an output end of the cylindrical power battery module is a cell unit at one end of a last sub-module along the first direction.

[0025] In one embodiment, the plurality of sub-modules are spaced apart along the second direction, an input end of the cylindrical power battery module is a cell unit at one end of a first sub-module along the second direction, and an output end of the cylindrical power battery module is a cell unit at one end of a last sub-module along the second direction.

[0026] In one embodiment, the plurality of sub-modules are spaced apart along a third direction, an input end of the cylindrical power battery module is a cell unit at one end of a first sub-module along the third direction, and an output end of the cylindrical power battery module is a cell unit at one end of a last sub-module along the third direction.

[0027] In one embodiment, the connecting copper bar comprises a copper bar body, a third end and a fourth end connected to the copper bar body and each connected to the cell unit of the adjacent submodule.

[0028] In one embodiment, the thickness of the third end and the fourth end are both less than the thickness of the copper bar body.

[0029] In one embodiment, the third end and the fourth end each have a thickness of 0.2 mm to 0.4 mm, and the copper bar body has a thickness of 3 mm to 5 mm.

[0030] In one embodiment, the third end has a number of third end connection portions corresponding to the conductive units on the same connection sheet, and the fourth end has a number of fourth end connection portions corresponding to the conductive units on the same connection sheet.

[0031] In one embodiment, at least one of the third end and the fourth end has a planar structure, or at least one of the third end and the fourth end has a protruding structure and includes a fourth buffer portion.

[0032] In an embodiment, the third end is provided with a fourth fusing structure, or the fourth buffer portion is provided with a fourth fusing structure.

[0033] In a second aspect, an embodiment of the present application further provides a cylindrical power battery module comprising the busbar assembly of any one of the above aspects and at least one sub-module, the sub-module comprising a plurality of cell units, and the busbar assembly configured to connect the cell units.

[0034] In one embodiment, the cylindrical power battery module includes a flexible circuit board connected to the cell contact system assembly and having an output plug, and a battery management system, the output plug being inserted into the battery management system.

[0035] In one embodiment, the cylindrical power battery module further comprises a negative temperature coefficient thermistor disposed in the cell unit and connected to the flexible circuit board.

[0036] In one embodiment, the cylindrical power battery module further comprises a plastic bracket disposed between the cell contact system assembly and the cell unit, and used to fix an input copper bar, an output copper bar and the cell contact system assembly. Effect of the Invention

[0037] The beneficial effects of the present application are as follows: The present application provides a busbar assembly for circuit connection of a cylindrical power battery module having at least one submodule having a plurality of cell units, the busbar assembly comprising an input copper bar, an output copper bar and a number of cell contact system assemblies corresponding to the submodules, the input copper bar is connected to the cell unit at the input end of the cylindrical power battery module, the output copper bar is connected to the cell unit at the output end of the cylindrical power battery module, and one submodule is connected corresponding to one cell contact system assembly to form an electric unit set, the cell contact system assembly comprises at least one connection sheet, the connection sheet comprises a plurality of conductive units and a plurality of connection parts, the conductive units arranged adjacent to each other at intervals along a first direction are connected by the connection parts, the conductive units are parallel to the cell units arranged adjacent to each other along the first direction, and the conductive units are serial to the cell units arranged adjacent to each other along the second direction.

[0038] The connecting sheet aligns the cell units arranged adjacent to each other along the first direction in one sub-module in parallel, distributes the current passing through the cell units arranged adjacent to each other along the first direction evenly, and reduces the current value passing through each cell unit. This ensures that the cell contact system assembly of the cylindrical power battery module can meet the overcurrent requirements when high-rate fast charging is performed, and ensures the reliability of the connection between the cell units. At the same time, since the current value passing through each cell unit is small, the thickness of the connecting sheet can be reduced to save space, thereby increasing the energy density of the cylindrical power battery module and reducing the manufacturing cost of the connecting sheet.

[0039] The present application further provides a cylindrical power battery module comprising the busbar assembly in the above embodiment and at least one sub-module, the sub-module comprising a plurality of cell units, and the busbar assembly configured to connect the cell units.

[0040] This cylindrical power battery module has a simple internal structure, and the circuit connection between the multiple cell units in the cylindrical power battery module can be completed by the input copper bars, the output copper bars and a number of cell contact system assemblies corresponding to the sub-modules. The connection by the cell contact system assemblies is highly reliable, and the space utilization rate is high, so that the energy density of the cylindrical power battery module is high. [Brief description of the drawings]

[0041] [Figure 1] FIG. 2 is a structural schematic diagram of a busbar assembly and a cell unit connected together according to an embodiment of the present application. [Diagram 2] 1 is a plan view showing a busbar assembly and a cell unit connected to each other according to an embodiment of the present application. FIG. [Diagram 3] 1 is a structural schematic diagram of a connection sheet according to an embodiment of the present application. [Figure 4] FIG. 2 is a partial enlarged view of a portion A in FIG. [Diagram 5] FIG. 2 is a partial enlarged view of a portion B in FIG. [Figure 6] FIG. 2 is a partial enlarged view of a portion C in FIG. [Figure 7] FIG. 2 is a structural schematic diagram of a cylindrical power battery module according to an embodiment of the present application. [Figure 8] FIG. 2 is a structural schematic diagram of a cell unit according to an embodiment of the present application. [Explanation of symbols]

[0042] 10···Submodule, 20···Cell contact system assembly, 30···Electric unit set, 100···Cell unit, 110···Positive electrode, 1100···Cylindrical protrusion, 120···Negative electrode, 200···Input copper bar, 201···First end of input copper bar, 202···Second end of input copper bar, 300···Output copper bar, 301···First end of output copper bar, 302···Second end of output copper bar, 2301···Input connection part, 303···Third buffer part, 400···Connection sheet, 410···Conductive unit, 4100···Protrusion, 411···First buffer part, 4000···Third buffer part 1 insulating layer, 4110···first fusing structure, 412···first connection area, 4120···second insulating layer, 413···second connection area, 4130···third insulating layer, 414···first relief groove, 420···connection portion, 4200···second buffer portion, 500···connection copper bar, 501···copper bar body, 502···third end, 5020···third end connection portion, 503···fourth end, 5030···fourth end connection portion, 504···fourth buffer portion, 600···flexible circuit board, 601···output plug, 602···nickel sheet, 700···NTC sampling point, 800···plastic bracket. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] In the description of this application, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, may be a fixed connection, a removable connection, or may be integrated, may be a mechanical connection, may be an electrical connection, may be a direct connection, may be an indirect connection via an intermediate medium, may be an internal communication between two elements, or may be an interaction relationship between two elements. A person skilled in the art can understand the meaning of the above terms in the present application depending on the situation.

[0044] In this application, unless otherwise expressly specified and limited, a first feature being "above" or "below" a second feature may include direct contact between the first feature and the second feature, or may include contact between the first feature and the second feature through another feature between them without direct contact. Furthermore, a first feature being "above," "upper," and "on the upper surface" of a second feature may include the first feature being directly above and diagonally above the second feature, or may simply indicate that the horizontal height of the first feature is higher than that of the second feature. A first feature being "below," "below," and "on the lower surface" of a second feature may include the first feature being directly below and diagonally below the second feature, or may simply indicate that the horizontal height of the first feature is smaller than that of the second feature.

[0045] In the description of the present embodiment, the orientations or positional relationships of the terms "upper", "lower", "left", "right" and the like are based on the orientations or positional relationships shown in the drawings, and are merely for ease of explanation and simplification of explanation, and do not indicate or imply that such devices or elements have a specific orientation, or must be configured and operated in a specific orientation. In addition, the terms "first" and "second" are merely used for distinction in the description, and do not have any special meaning.

[0046] 1 and 2, this embodiment provides a busbar assembly for circuit connection of a cylindrical power battery module (e.g., the cylindrical power battery module is a large cylindrical power battery module), the cylindrical power battery module includes at least one sub-module 10, each sub-module 10 includes a plurality of cell units 100 arranged adjacent to each other, the plurality of cell units 100 are arranged along a first direction and a second direction, and there is a gap between the plurality of cell units 100. The first direction is the X-axis direction in FIG. 1, and the second direction is the Y-axis direction in FIG. 1.

[0047] In one embodiment, the first direction and the second direction are different, and preferably, the first direction and the second direction are perpendicular.

[0048] In some embodiments, one sub-module 10 is provided, the input end of the cylindrical power battery module is the cell unit 100 at the first end of the sub-module 10, and the output end of the cylindrical power battery module is the cell unit 100 at the second end of the sub-module 10. The bus bar assembly provided in the cylindrical power battery module includes an input copper bar 200, an output copper bar 300, and a number of cell contact systems corresponding to the number of sub-modules 10. The CCS (Converter Copper Assembly) assembly 20 includes an input copper bar 200 connected to the cell unit 100 at the input end of the cylindrical power battery module, and when the input copper bar 200 is connected to the positive electrode 110 of the cell unit 100 at the input end of the submodule 10, the output copper bar 300 is connected to the negative electrode 120 of the cell unit 100 at the output end of the submodule 10, and when the input copper bar 200 is connected to the negative electrode 120 of the cell unit 100 at the input end of the submodule 10, the output copper bar 300 is connected to the positive electrode 110 of the cell unit 100 at the output end of the submodule 10. For the sake of convenience, the following embodiments are unified so that the input copper bar 200 is connected to the negative electrode 120 of the cell unit 100 at the input end and the output copper bar 300 is connected to the positive electrode 110 of the cell unit 100 at the output end. The output copper bar 300 is connected to the cell unit 100 at the output end of the cylindrical power battery module. Each CCS assembly 20 comprises at least one connection sheet 400, the connection sheet 400 comprising a plurality of conductive units 410 and a plurality of connection portions 420, the conductive units 410 arranged adjacent to each other at intervals along a first direction being connected by the connection portions 420, the conductive units 410 being parallel to the cell units 100 arranged adjacent to each other along the first direction, and at the same time, the conductive units 410 being in series with the cell units 100 arranged adjacent to each other along the second direction.

[0049] As a result, the connection sheet 400 allows the cell units 100 arranged adjacent to each other along the second direction in the submodule 10 to be connected in series in the same row via the conductive units 410 arranged adjacent to each other along the second direction; at the same time, the connection sheet 400 allows the cell units 100 arranged adjacent to each other along the first direction in the submodule 10 to be connected in parallel, so as to distribute the current of the multiple cell units 100 arranged in parallel along the first direction evenly, and reduce the current value passing through each cell unit 100, thereby ensuring that the CCS assembly 20 can meet the overcurrent requirements when high-rate fast charging is performed, and ensuring the reliability of the connection between the cell units 100; at the same time, because the current value passing through each cell unit 100 is small, the thickness of the connection sheet 400 can be reduced to save space, and the energy density of the cylindrical power battery module can be increased.

[0050] In a preferred embodiment, the number of the connection sheets 400 in the CCS assembly 20 and the number of the conductive units 410 in each connection sheet 400 are adapted to the number of the cell units 100 in the sub-module 10 .

[0051] 3, the conductive unit 410 in this embodiment preferably includes a first connection region 412 and a second connection region 413, and the first connection region 412 and the second connection region 413 are respectively connected to two adjacent cell units 100 arranged along the first direction, and for convenience of description, the two adjacent cell units 100 are defined as a first cell and a second cell, and the positive electrodes 110 and negative electrodes 120 of the first cell and the second cell are both arranged on the same side. Exemplarily, the first connection region 412 is connected to the positive electrode 110 of the first cell, and the second connection region 413 is connected to the negative electrode 120 of the second cell, thus completing a series connection between a plurality of cell units 100 arranged along the second direction.

[0052] 8, the cell unit 100 includes a positive electrode 110 and a negative electrode 120. The negative electrode 120 is provided on an end face of the cell unit 100. A cylindrical protrusion 1100 is provided at a position located at the center of the end face. The cylindrical protrusion 1100 is a part of the positive electrode 110. Since the height of the positive electrode 110 of the cell unit 100 is higher than the height of the negative electrode 120 of the cell unit 100, in this embodiment, the first connection region 412 and the second connection region 413 are provided at different heights in the third direction. 1 , and the height of the first connection area 412 along the Z-axis direction is higher than the height of the second connection area 413 to accommodate the height difference between the positive electrode 110 and the negative electrode 120, thereby preventing the cylindrical power battery module from being loose in the cell units 100 during use, which may cause the connection sheet 400 to be subjected to tensile or pressure for a long time, resulting in wrinkles and even breakage, thereby reducing the reliability of the connection between the cell units 100 of the cylindrical power battery module.

[0053] In one embodiment, the third direction is different from both the first direction and the second direction, and preferably, both the first direction and the second direction are perpendicular to the third direction.

[0054] Preferably, in order to avoid the positive electrode 110 of the cell unit 100, the conductive unit 410 in this embodiment is further provided with a first escape groove 414, which is an arc-shaped notch that matches the cylindrical protrusion 1100 of the positive electrode 110. The provision of the first escape groove 414, on the one hand, increases the connection area between the second connection region 413 and the negative electrode 120, improves the reliability of the connection between the second connection region 413 and the negative electrode 120, and makes it less likely that a temporary connection will occur; on the other hand, the first escape groove 414 can also play a role in regulating position, so as to prevent the connection sheet 400 from falling off or becoming misaligned.

[0055] In some embodiments, the conductive unit 410 may be provided as a planar structure, and the connection sheet 400 is cut to produce a preset shape, such a processing method is easy, efficient, and low cost. Of course, in other embodiments, the conductive unit 410 may be cast by a mold, as long as it can achieve a preset shape. The conductive unit 410 is provided with a first fusing structure 4110, which is provided at the connection between the first connection region 412 and the second connection region 413. The first fusing structure 4110 has a first current-limiting hole opened at the connection point between the first connection region 412 and the second connection region 413, and at least one first current-limiting hole may be provided according to actual needs. The installation of the first current-limiting hole reduces the cross-sectional area of ​​the connection point between the first connection region 412 and the second connection region 413 of the conductive unit 410, so that when the circuit is overloaded, the first connection region 412 and the second connection region 413 will be disconnected, thereby playing a protective role for the circuit and improving the safety performance of the cylindrical power battery.

[0056] Preferably, the first fusing structure 4110 further comprises a low melting point metal, such as tin, applied to the connection point between the first connection region 412 and the second connection region 413. When an extreme situation such as a short circuit occurs in the circuit, the current in the circuit will increase rapidly, and the increase in current will cause the temperature of the circuit to increase, and the temperature will rise until it causes the low melting point metal to melt. When the low melting point metal melts, the substrate of the conductive unit 410 will become brittle and prone to breakage, allowing the first connection region 412 and the second connection region 413 to be quickly disconnected, with a fast response speed, and the circuit along the second direction will be quickly cut off, thereby avoiding damage to the cell units 100 arranged adjacent to each other along the second direction.

[0057] Of course, in other embodiments, the conductive unit 410 is provided with a protrusion 4100, which forms a first buffering part 411, and both ends of the first buffering part 411 are respectively connected to a first connection region 412 and a second connection region 413, and the provision of the first buffering part 411 provides a certain buffering effect against the expansion force, tolerance and displacement between the cell units 100 adjacent to each other along the second direction, thereby preventing breakage of the conductive unit 410, improving the toughness of the conductive unit 410 and ensuring high connection reliability. Preferably, the protrusion 4100 of the conductive unit 410 is provided in a square shape, and the protrusion 4100 of the conductive unit 410 may be manufactured by pressing, which is simple to process and has good buffering effect.

[0058] For example, the first fusing structure 4110 may be provided in the first buffering part 411, and when an extreme situation such as a short circuit occurs in the circuit and the temperature of the circuit becomes too high, the first fusing structure 4110 melts due to self-heating, and quickly cuts off the circuit connection between the cell units 100 adjacent to each other along the second direction, thereby protecting the cell units 100. The first fusing structure 4110 has a first current-limiting hole provided in the first buffering part 411, and at least one first current-limiting hole may be provided according to actual needs, and the provision of the first current-limiting hole reduces the cross-sectional area of ​​the conductive unit 410 in the first buffering part 411, so that when the circuit is overloaded, the conductive unit 410 is cut off, thereby playing a protective role for the circuit and improving the safety performance of the cylindrical power battery. Preferably, the first buffer portion 411 may be coated with a low melting point metal, such as tin, thereby ensuring that the first connection region 412 and the second connection region 413 are quickly disconnected, resulting in a fast response speed and avoiding damage to the cell units 100 arranged adjacent to each other along the second direction.

[0059] Preferably, in some embodiments, the connection portion 420 is a planar structure, and the size of the connection portion 420 is much smaller than the size of the conductive unit 410, so that a narrow neck is formed between adjacent conductive units 410, and the narrow neck itself may be a second fusing structure, and when an extreme situation such as a short circuit occurs in the circuit, the narrow neck melts due to the concentration of thermal stress to cut off the current in the circuit, thereby protecting the circuit and preventing the cell units 100 adjacent to each other along the first direction from being damaged, further reducing losses and saving costs, and at the same time, the defective large cylindrical battery can be quickly found, which is advantageous for later maintenance and replacement. Of course, in other embodiments, the second fusing structure further comprises a low melting point metal, such as tin, applied to the narrow neck.

[0060] In one embodiment, the connection part 420 may be provided as a protruding structure, and the protruding structure of the connection part 420 is the second buffer part 4200. The provision of the second buffer part 4200 provides a certain buffering effect against the expansion force, tolerance and displacement between the cell units 100 adjacent to each other along the first direction, thereby preventing the connection part 420 from breaking, improving the toughness of the connection part 420 and ensuring a high connection reliability. Preferably, the protruding structure of the connection part 420 is provided in a square shape, and the protruding structure of the connection part 420 may be manufactured by a pressing method, which is simple to process and has a good buffering effect.

[0061] For example, the second fusing structure may be provided in the second buffer part 4200, the second fusing structure may include a second current-limiting hole opened in the connection part 420, the second current-limiting hole may be one or more according to actual needs, the second current-limiting hole may reduce the cross-sectional area at the connection part 420, and when the circuit is overloaded, the connection part 420 may be cut off, which plays a protective role for the circuit and improves the safety performance of the cylindrical power battery. Preferably, the second fusing structure further includes a low melting point metal, such as tin, applied to the connection part 420, and when an extreme situation such as a short circuit occurs in the circuit, the current in the circuit increases rapidly and the temperature rises to cause the low melting point metal to melt, and when the low melting point metal melts, the substrate of the connection part 420 becomes brittle and easy to be cut off, which allows the circuit connection along the first direction to be quickly cut off, and prevents the cell units 100 adjacent to each other along the first direction from being damaged.

[0062] Preferably, the conductive units 410 and the connection parts 420 of the connection sheet 400 are integrally formed, the conductive units 410 and the connection parts 420 have the same thickness, and the thickness of the connection sheet 400 is set to 0.2 mm to 0.4 mm. Exemplarily, the thickness of the connection sheet 400 is set to 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, or 0.4 mm, etc. Of course, in other embodiments, the thickness of the connection sheet 400 may be set to other sizes within this range.

[0063] Preferably, the connection sheet 400 includes a first insulating layer 4000, a second insulating layer 4120, and a third insulating layer 4130, the first insulating layer 4000 being provided on one side of at least one of the first buffer section 411 and the second buffer section 4200, which is close to the cell unit 100, the second insulating layer 4120 being provided in the first connection region 412, and configured to isolate the portion of the first connection region 412 other than the portion connected to the cell unit 100, and the third insulating layer 4130 being provided in the second connection region 413, and configured to isolate the portion of the second connection region 413 other than the portion connected to the cell unit 100. The provision of the first insulating layer 4000, the second insulating layer 4120, and the third insulating layer 4130 prevents the cell unit 100 from being short-circuited, and the safety of the circuit connection is high.

[0064] As shown in FIG. 4, the input copper bar 200 is a variable cross-section copper bar, and includes a first end 201 of the input copper bar and a second end 202 of the input copper bar. The first end 201 of the input copper bar is connected to the cell unit 100 at the input end of the cylindrical power battery module, and the thickness of the first end 201 of the input copper bar is smaller than the thickness of the second end 202 of the input copper bar. Preferably, the thickness of the first end 201 of the input copper bar is 0.2mm to 0.4mm, and the thickness of the second end 202 of the input copper bar is 3mm to 5mm. Exemplarily, the thickness of the first end 201 of the input copper bar may be set to 0.2mm, 0.25mm, 0.3mm, 0.35mm, or 0.4mm, etc. Of course, in other embodiments, the thickness of the first end 201 of the input copper bar may be set to other sizes within this range. The thickness of the second end 202 of the input copper bar is 3mm, 3.5mm, 4mm, 4.5mm, or 5mm, etc. Of course, in other embodiments, the thickness of the second end 202 of the input copper bar may be set to other sizes within this range.

[0065] Preferably, the first end 201 of the input copper bar has a number of input connection parts 2301 corresponding to the conductive units 410 in the same connection sheet 400. In this embodiment, four conductive units 410 are taken as an example, and the four input connection parts 2301 are respectively connected to the four cell units 100 at the input end of this submodule 10, thereby realizing the dispersion of current in the input copper bar 200. It is emphasized that since the first end 201 of the input copper bar is connected to the negative electrode 120 of the cell unit 100, the first end 201 of the input copper bar and the second end 202 of the input copper bar can be designed to have a similar height difference according to the height difference between the positive electrode 110 and the negative electrode 120 of the cell unit 100 in order to maintain the overall flatness.

[0066] Preferably, the first end 201 of the input copper bar has a planar structure, and the first end 201 of the input copper bar is provided with a second escape groove, which is an arc-shaped notch that matches the cylindrical protrusion 1100 of the positive electrode 110 of the cell unit 100. The second escape groove can avoid the positive electrode 110 of the cell unit 100 connected to the first end 201 of the input copper bar, and can play a role in position regulation to prevent the input copper bar from falling off or being misaligned. In addition, such an installation increases the connection area between the first end 201 of the input copper bar and the negative electrode 120 of the cell unit 100, improves the reliability of the connection, and makes it less likely that a temporary connection will occur.

[0067] As shown in FIG. 5, the output copper bar 300 is a variable cross-section copper bar, and includes a first end 301 of the output copper bar and a second end 302 of the output copper bar. The first end 301 of the output copper bar is connected to the cell unit 100 at the output end of the cylindrical power battery module, and the thickness of the first end 301 of the output copper bar is smaller than the thickness of the second end 302 of the output copper bar. The thickness of the first end 301 of the output copper bar is 0.2mm to 0.4mm, and the thickness of the second end 302 of the output copper bar is 3mm to 5mm. Exemplarily, the thickness of the first end 301 of the output copper bar may be set to 0.2mm, 0.25mm, 0.3mm, 0.35mm, or 0.4mm, etc. Of course, in other embodiments, the thickness of the first end 301 of the output copper bar may be set to other sizes within this range. The thickness of the second end 302 of the output copper bar is 3mm, 3.5mm, 4mm, 4.5mm, or 5mm, etc. Of course, in other embodiments, the thickness of the second end 302 of the output copper bar may be set to other sizes within this range.

[0068] Preferably, the first end 301 of the output copper bar also has a number of input connection parts 2301 corresponding to the conductive units 410 in the same connection sheet 400. In this embodiment, four conductive units 410 are taken as an example for explanation, and the four input connection parts 2301 are respectively connected to the four cell units 100 at the output end of this submodule 10, thereby realizing the current merging at the output copper bar 300. It is emphasized that since the first end 301 of the output copper bar is connected to the positive electrode 110 of the cell unit 100, the first end 301 of the output copper bar and the second end 302 of the output copper bar can be designed to have a similar height difference according to the height difference between the positive electrode 110 and the negative electrode 120 of the cell unit 100 in order to maintain the overall flatness.

[0069] In some embodiments, the first end 301 of the output copper bar is a planar structure, and the third fusing structure comprises a third current-limiting hole opened at the first end 301 of the output copper bar, and the third current-limiting hole may be one or more according to actual needs, and the third current-limiting hole is provided to reduce the cross-sectional area of ​​the first end 301 of the output copper bar, so that when the circuit is overloaded, the input connection part 2301 is melted due to the concentration of thermal stress, cutting off the current in the circuit, thereby playing a protective role for the circuit and improving the safety performance of the cylindrical power battery. Preferably, the third fusing structure further comprises a low melting point metal, such as tin, coated on the first end 301 of the output copper bar, and when an extreme situation such as a short circuit occurs in the circuit, the low melting point metal melts, which makes the base material of the first end 301 of the output copper bar brittle, allowing the first end 301 of the output copper bar to be quickly cut off, which has a faster response speed and plays a role in quickly cutting off the circuit to protect the cell unit 100.

[0070] In another embodiment, the first end 301 of the output copper bar may be provided as a protruding structure, and the protruding structure of the first end 301 of the output copper bar is the third buffer part 303. The third buffer part 303 provides a certain buffering effect against the expansion force, tolerance and displacement between the output copper bar 300 and the cell unit 100, and the connection is highly reliable. Preferably, the protruding structure of the first end 301 of the output copper bar is provided in a "box" shape and may be manufactured by pressing, which is simple to process and has a good buffering effect. In addition, a third fusing structure may be provided in the third buffer part 303. When an extreme situation such as a short circuit occurs in the circuit and the circuit temperature becomes too high, the third fusing structure melts due to self-heating, and quickly cuts off the circuit connection between the output copper bar 300 and the cell unit 100, thereby playing a role in protecting the cell unit 100.

[0071] In some embodiments, the sub-modules 10 may be multiple, and in this case, the CCS assembly 20 further includes a connecting copper bar 500, and each sub-module 10 is connected to a corresponding CCS assembly 20 to form an electric unit set 30. The connecting copper bar 500 connects adjacent electric unit sets 30 except for the input end of the cylindrical power battery module and the output end of the cylindrical power battery module to form an assembly of multiple sub-modules 10. During discharge, the flow direction of current starts from the input end of the cylindrical power battery module, passes through the sub-module 10 where the input end of the cylindrical power battery module is located, through the connecting copper bar 500, and through the sub-module 10 where the input end is located. The current flows sequentially through the adjacent submodules 10, the connecting copper bar 500, and the submodule 10 where the output end of the cylindrical power battery module is located, and finally flows out through the output end of the cylindrical power battery module, and the reverse occurs during charging. For convenience of explanation, three submodules 10 are taken as an example for explanation. As shown in FIG. 1, the three submodules 10 are spaced apart along a first direction, and the input end of the cylindrical power battery module is the cell unit 100 at one end of the first submodule 10 along the first direction and is connected to the input copper bar 200, and the output end of the cylindrical power battery module is the cell unit 100 at one end of the last submodule 10 along the first direction and is connected to the output copper bar 300.

[0072] Preferably, the three sub-modules 10 are connected by a connecting copper bar 500. For convenience of explanation, the three sub-modules 10 are defined herein as a first module, a second module and a third module. As shown in FIG. 1 and FIG. 6, taking discharge as an example, the input end of the cylindrical power battery module is the beginning end of the first module, and the output end of the cylindrical power battery module is the end of the third module. In this embodiment, there are two connecting copper bars 500, and each of the two connecting copper bars 500 has a copper bar body 501, a third end 502 and a fourth end 503 connected to the copper bar body 501. For convenience of explanation, the two connecting copper bars 500 are defined as the first copper bar. and a second copper bar, wherein the third end 502 of the first copper bar is connected to the positive electrode 110 of the cell unit 100 at the output end of the first module, the fourth end 503 of the first copper bar is connected to the negative electrode 120 of the cell unit 100 at the input end of the second module, the third end 502 of the second copper bar is connected to the positive electrode 110 of the cell unit 100 at the output end of the second module, and the fourth end 503 of the second copper bar is connected to the negative electrode 120 of the cell unit 100 at the input end of the third module, so that the installation manner of the connecting copper bar 500 connects the three sub-modules 10 in series together to realize stable charging and discharging of the cylindrical power battery module.

[0073] Preferably, the third end 502 has a number of third end connection parts 5020 corresponding to the conductive units 410 on the same connection sheet 400, and the fourth end 503 has a number of fourth end connection parts 5030 corresponding to the conductive units 410 on the same connection sheet 400. In this embodiment, four conductive units 410 are taken as an example, and the four third end connection parts 5020 are respectively connected to the four cell units 100 at the output end of the first module, and the four fourth end connection parts 5030 are respectively connected to the four cell units 100 at the input end of the second module, thereby completing the series connection between the first module and the second module.

[0074] Preferably, in order to maintain overall flatness, there is a height difference between the third end 502 and the fourth end 503 of the connecting copper bar 500 and the connecting copper bar main body 501 that matches the height difference between the positive electrode 110 and the negative electrode 120 of the cell unit 100.

[0075] Preferably, the thickness of the third end 502 and the fourth end 503 are both smaller than the thickness of the copper bar body 501. The thickness of the third end 502 and the fourth end 503 are both 0.2 mm to 0.4 mm, and the thickness of the copper bar body 501 is 3 mm to 5 mm. Exemplarily, the thickness of the third end 502 and the fourth end 503 may be set to 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, or 0.4 mm, etc. Of course, in other embodiments, the thickness of the third end 502 and the fourth end 503 may be set to other sizes within this range. The thickness of the copper bar body 501 is 3 mm, 3.5 mm, 4 mm, 4.5 mm, or 5 mm, etc. Of course, in other embodiments, the thickness of the copper bar body 501 may be set to other sizes within this range.

[0076] Preferably, in some embodiments, the third end 502 is provided as a planar structure, and the third end 502 is provided with a fourth fusing structure. Exemplarily, the fourth fusing structure includes a fourth current-limiting hole opened in the third end 502, and the fourth current-limiting hole may be one or more according to actual needs. The fourth current-limiting hole is provided to reduce the cross-sectional area of ​​the third end 502, so that when the circuit is overloaded, the third end 502 is melted due to the concentration of thermal stress to cut off the current in the circuit, thereby playing a protective role for the circuit and improving the safety performance of the cylindrical power battery. Preferably, the fourth fusing structure further includes a low-melting point metal, such as tin, applied to the third end 502, and when an extreme situation such as a short circuit occurs in the circuit, the low-melting point metal melts, which makes the base material of the third end 502 brittle, allowing the third end 502 to be quickly cut off, which has a faster response speed and plays a role in quickly cutting off the circuit to protect the cell unit 100.

[0077] In another embodiment, the third end 502 is provided as a protruding structure, and the protruding structure of the third end 502 is a fourth buffer part 504. The fourth buffer part 504 provides a certain buffering effect against the expansion force, tolerance and displacement between the connecting copper bar 500 and the cell unit 100, and the connection is highly reliable. Preferably, the protruding structure of the third end 502 is provided in a "box" shape and may be manufactured by pressing, which is simple to process and has a good buffering effect. Exemplarily, a fourth fusing structure may be provided in the fourth buffer part 504. When an extreme situation such as a short circuit occurs in the circuit and the circuit temperature becomes too high, the fourth fusing structure melts due to self-heating, and quickly cuts off the circuit connection between the connecting copper bar 500 and the positive electrode 110 of the cell unit 100, thereby playing a role in protecting the cell unit 100.

[0078] In some embodiments, the fourth end 503 has a planar structure, and in order to avoid the positive electrode 110 of the cell unit 100, the fourth end 503 of the connecting copper bar 500 is provided with a third escape groove, which is an arc-shaped notch that matches the cylindrical protrusion 1100 of the positive electrode 110. The provision of the third escape groove, on the one hand, increases the connection area between the fourth end 503 of the connecting copper bar 500 and the negative electrode 120, improves the reliability of the connection between the fourth end 503 of the connecting copper bar 500 and the negative electrode 120, and makes it difficult for a temporary connection to occur; on the other hand, the third escape groove can also play a role in regulating the position, so as to prevent the connecting copper bar 500 from falling off or being displaced.

[0079] Of course, in other embodiments, when there are multiple sub-modules 10, multiple electric unit sets 30 may be spaced apart along the second direction to meet the installation needs of different cylindrical power battery modules, and the input end of the cylindrical power battery module is the cell unit 100 at one end of the first sub-module 10 along the second direction, and the output end of the cylindrical power battery module is the cell unit 100 at one end of the last sub-module 10 along the second direction.

[0080] In some embodiments, multiple electric unit sets 30 may be spaced apart along the third direction, and the input end of the cylindrical power battery module is the cell unit 100 at one end of the first sub-module 10 along the third direction, and the output end of the cylindrical power battery module is the cell unit 100 at one end of the last sub-module 10 along the third direction; adaptively, when multiple sub-modules 10 are spaced apart along the third direction, the third end 502 and the fourth end 503 of the connecting copper bar 500 are spaced apart along the third direction, thereby adaptively connecting two sub-modules 10 spaced apart along the third direction.

[0081] The present application further provides a cylindrical power battery module including the busbar assembly and at least one sub-module 10 in the above embodiment, the sub-module 10 including a plurality of cell units 100, and the busbar assembly configured to connect the cell units 100. The cylindrical power battery module has a simple internal structure, and the input copper bar 200, the output copper bar 300, and the number of CCS assemblies 20 corresponding to the sub-modules 10 can complete the circuit connection between the plurality of cell units 100 in the cylindrical power battery module, the reliability of the connection by the CCS assemblies 20 is high, and the space utilization rate is high, and the energy density of the cylindrical power battery module is high.

[0082] 1 and 7, the cylindrical power battery module includes a flexible printed circuit board (FPC) 600 and a BMS, the FPC 600 is provided with a nickel sheet 602 and an output plug 601, a plurality of nickel sheets 602 are provided, and both ends of the plurality of nickel sheets 602 are respectively connected to the FPC 600 and the connection sheet 400, and the number of nickel sheets 602 provided can be selected according to the actual situation, and the output plug 601 is inserted into the BMS, and the voltage sampling work of the cell unit 100 of each sub-module 10 can be completed by the FPC 600 and the BMS. The output plug 601 is directly inserted into the BMS, which reduces the use of intermediate relay harnesses, which occupies a small space, has a simple installation process, and has low labor costs, which is favorable for efficient industrial production.

[0083] 1 and 8, the cylindrical power battery module is equipped with an NTC thermistor, which is welded to the FPC 600 by a nickel sheet 602. In order to achieve accurate temperature measurement, in this embodiment, the top cover of the negative electrode 120 of the cell unit 100 located at the beginning of the first module is provided with an NTC measurement point 700, and the NTC thermistor is attached to this NTC measurement point 700, which solves the problem that it is difficult to measure the temperature of the cylindrical power battery module, and realizes accurate measurement of the temperature of the cell unit 100. Of course, in other embodiments, the NTC measurement point 700 can be provided on the pole of the positive electrode 110 of the cell unit 100 or at the middle position of the cell unit 100, thereby ensuring that the measured temperature of the cell unit 100 is accurate.

[0084] Continuing to refer to FIG. 7, the cylindrical power battery module further includes a plastic bracket 800, which is disposed between the CCS assembly 20 and the cell unit 100. The plastic bracket 800 is provided with a tracing hole, through which the input copper bar 200, the output copper bar 300 and the CCS assembly 20 can be positioned and assembled with a plurality of cell units 100. The plastic bracket 800 can place the input copper bar 200, the output copper bar 300 and the CCS assembly 20 and play a role of fixing. At the same time, the cell unit 100 and the input copper bar 200, the output copper bar 300 and the CCS assembly 20 can be integrated, the number of assembled (PACK) parts can be reduced, the process flow is simple, and the cost is low. At the same time, the short circuit risk between the cell unit 100 and the input copper bar 200, the output copper bar 300 and the CCS assembly 20 can be further reduced, thereby ensuring the electrical safety of the cylindrical power battery module.

[0085] Preferably, the plastic bracket 800 is one-piece molded, which has a simple manufacturing process and low cost.

Claims

1. A busbar assembly for circuit connection of a cylindrical power battery module comprising at least one sub-module (10) comprising a plurality of cell units (100), comprising: an input copper bar (200) connected to the cell unit (100) at the input end of the cylindrical power battery module; An output copper bar (300) connected to the cell unit (100) at the output end of the cylindrical power battery module; and a cell contact system assembly (20) corresponding in number to the sub-modules (10), One of the sub-modules (10) is connected to one of the cell contact system assemblies (20) to form an electric unit set (30), the cell contact system assembly (20) includes at least one connection sheet (400), the connection sheet (400) includes a plurality of conductive units (410) and a plurality of connection portions (420), the conductive units (410) arranged adjacent to each other and spaced apart along a first direction are connected by the connection portions (420), the conductive units (410) are arranged in parallel with the cell units (100) arranged adjacent to each other along the first direction, and the conductive units (410) are arranged in series with the cell units (100) arranged adjacent to each other along a second direction, The cell unit (100) comprises a positive electrode (110) and a negative electrode (120), the negative electrode (120) is provided on an end face of the cell unit (100), the positive electrode (110) is provided on the same side as the negative electrode (120), the positive electrode (110) comprises a cylindrical protrusion (1100), and the conductive unit (410) is provided with a first escape groove (414) capable of avoiding the cylindrical protrusion (1100); The first relief groove (414) is an arc-shaped notch that matches the cylindrical protrusion (1100) of the positive electrode (110); At least one of the input copper bar (200) and the output copper bar (300) is a variable cross-section copper bar, and the input copper bar (200) and the output copper bar (300) each have a first end and a second end, the first end (201) of the input copper bar (200) is connected to the cell unit (100) at the input end of the cylindrical power battery module, and the first end (301) of the output copper bar (300) is connected to the cell unit (100) at the output end of the cylindrical power battery module, the thickness of the first end (201) of the input copper bar (200) is smaller than the thickness of the second end (202) of the input copper bar (200), and the thickness of the first end (301) of the output copper bar (300) is smaller than the thickness of the second end (302) of the output copper bar (300); Busbar assembly.

2. The conductive unit (410) is provided with a convex portion (4100) forming a first buffer portion (411); The busbar assembly of claim 1 .

3. The first buffer portion (411) is provided with a first fusing structure (4110). The busbar assembly of claim 2 .

4. The thickness of the connection sheet (400) is 0.2 mm to 0.4 mm; The busbar assembly of claim 1 .

5. The connection sheet (400) includes a first insulating layer (4000) provided on one side of the connection sheet (400) close to the cell unit (100); The busbar assembly of claim 1 .

6. The connecting portion (420) has a planar structure, or the connecting portion (420) has a protruding structure and includes a second buffer portion (4200); The busbar assembly of claim 1 .

7. The connection portion (420) is provided with a second fusing structure, or the second buffer portion (4200) is provided with a second fusing structure. The busbar assembly of claim 6.

8. The conductive unit (410) includes a first connection region (412) and a second connection region (413) each connected to two of the cell units (100) adjacent to each other along the first direction. The busbar assembly of claim 1 .

9. The first connection region (412) and the second connection region (413) have different heights in a third direction, The third direction is different from both the first direction and the second direction. The busbar assembly of claim 8.

10. The first connection region (412) includes a second insulating layer (4120) configured to isolate a portion of the first connection region (412) other than the portion connected to the cell unit (100); The second connection region (413) includes a third insulating layer (4130) configured to isolate a portion of the second connection region (413) other than the portion connected to the cell unit (100). The busbar assembly of claim 8.

11. The thickness of the first end is 0.2 mm to 0.4 mm, and the thickness of the second end is 3 mm to 5 mm. The busbar assembly of claim 1 .

12. The first end portion has a number of input connection portions (2301) corresponding to the number of conductive units (410) on the same connection sheet (400). The busbar assembly of claim 1 .

13. The first end has a planar structure, or the first end has a protruding structure and includes a third buffer portion (303); The busbar assembly of claim 1 .

14. The first end portion is provided with a third fusing structure, or the third buffer portion (303) is provided with a third fusing structure. The busbar assembly of claim 13.

15. There is one sub-module (10), an input end of the cylindrical power battery module is the cell unit (100) at a first end of the sub-module (10), and an output end of the cylindrical power battery module is the cell unit (100) at a second end of the sub-module (10); The busbar assembly according to any one of claims 1 to 14.

16. The sub-modules (10) are multiple, and the cell contact system assembly (20) further includes a connecting copper bar (500) connecting adjacent sub-modules (10) except for the input end of the cylindrical power battery module and the output end of the cylindrical power battery module. The busbar assembly according to any one of claims 1 to 14.

17. The plurality of sub-modules (10) are spaced apart along the first direction, an input end of the cylindrical power battery module is a cell unit (100) at one end of a first sub-module (10) along the first direction, and an output end of the cylindrical power battery module is a cell unit (100) at one end of a last sub-module (10) along the first direction. The busbar assembly of claim 16.

18. The plurality of sub-modules (10) are spaced apart along the second direction, an input end of the cylindrical power battery module is a cell unit (100) at one end of a first sub-module (10) along the second direction, and an output end of the cylindrical power battery module is a cell unit (100) at one end of a last sub-module (10) along the second direction. The busbar assembly of claim 16.

19. The plurality of sub-modules (10) are spaced apart along a third direction, an input end of the cylindrical power battery module is a cell unit (100) at one end of a first sub-module (10) along the third direction, and an output end of the cylindrical power battery module is a cell unit (100) at one end of a last sub-module (10) along the third direction; The third direction is different from both the first direction and the second direction. The busbar assembly of claim 16.

20. The connecting copper bar (500) comprises a copper bar body (501), a third end (502) and a fourth end (503) connected to the copper bar body (501) and connected to the cell unit (100) of the submodule (10) adjacent to each other. The busbar assembly of claim 16.

21. The thickness of the third end (502) and the fourth end (503) are both smaller than the thickness of the copper bar body (501); 21. The busbar assembly of claim 20.

22. The thickness of the third end (502) and the fourth end (503) is 0.2 mm to 0.4 mm, and the thickness of the copper bar body (501) is 3 mm to 5 mm; 22. The busbar assembly of claim 21.

23. The third end (502) has a number of third end connection portions (5020) corresponding to the number of the conductive units (410) in the same connection sheet (400), and the fourth end (503) has a number of fourth end connection portions (5030) corresponding to the number of the conductive units (410) in the same connection sheet (400).

21. The busbar assembly of claim 20.

24. At least one of the third end (502) and the fourth end (503) has a planar structure, or at least one of the third end (502) and the fourth end (503) has a convex structure and includes a fourth buffer portion (504); 24. The busbar assembly of claim 23.

25. The third end (502) is provided with a fourth fusing structure, or the fourth buffer portion (504) is provided with a fourth fusing structure.

25. The busbar assembly of claim 24.

26. A busbar assembly according to any one of claims 1 to 14 and at least one sub-module (10), the sub-module (10) comprising a plurality of cell units (100), the busbar assembly being configured to connect the cell units (100). Cylindrical power battery module.

27. A flexible circuit board (600) connected to the cell contact system assembly (20) and provided with an output plug (601), and a battery management system, The output plug (601) is inserted into the battery management system; 27. The cylindrical power battery module of claim 26.

28. A negative temperature coefficient thermistor is provided in the cell unit (100) and connected to the flexible circuit board (600).

28. The cylindrical power battery module of claim 27.

29. The cell contact system assembly further includes a plastic bracket (800) provided between the cell contact system assembly (20) and the cell unit (100) and configured to fix an input copper bar (200), an output copper bar (300) and the cell contact system assembly (20).

27. The cylindrical power battery module of claim 26.

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