Busbar assembly, battery module and battery pack

Abstract

Busbar assembly used for a cylindrical power battery module (10), wherein the cylindrical power battery module (10) comprises several cells (100), and the busbar assembly comprises a positive terminal strip (210), a negative terminal strip (240), a series strip (230) and a terminal strip (220), wherein: the terminal strip (220) is arranged on a cylindrical power battery module (10), wherein the terminal strip (220) is designed to connect two adjacent cells (100) in series in a first direction, and the terminal strip (220) is designed to connect two adjacent cells (100) in parallel in a second direction; the series strip (230) is arranged such that it connects two adjacent cylindrical power battery modules (10) in series to form a battery group; the positive terminal strip (210) is connected to the positive terminal end of the cell (100) at a positive output end of a battery group; the negative terminal strip (240) is connected to the negative terminal end of the cell (100) at a negative output end of the battery group, and the parts where the terminal strip (220), the series strip (230) and the negative terminal strip (240) are each connected to the negative terminal end of the corresponding cell (100) are defined as negative terminal sections, wherein at least one separating groove (270) is provided on the negative terminal section, which serves to divide the negative terminal section in a second direction into at least two separating parts, each separating part being connected to the negative terminal end of the cell (100).

Description

TECHNICAL AREA

[0001] The present application relates to the field of battery technology, in particular a busbar assembly, a battery module and a battery pack. STATE OF THE ART

[0002] The battery module consists of several cells connected in series or parallel via a busbar in a specific manner. For example, existing technology discloses a busbar assembly and a cylindrical power battery module. This busbar assembly serves as the electrical circuit connection for the cylindrical power battery module and comprises an input copper busbar, an output copper busbar, and a number of CCS components corresponding to the submodules. The input copper busbar is connected to the cell units on the input side of the cylindrical power battery module, and the output copper busbar is connected to the cell units on the output side of the cylindrical power battery module.The CCS components are connected in series and parallel with the cell units of the sub-modules, which increases the reliability of the connection between the cell units, saves space and increases yield.

[0003] However, during charging and discharging of the battery module or battery pack, the cells undergo a certain expansion phenomenon towards the busbar assembly. This phenomenon becomes even more pronounced after prolonged use of the battery module or battery pack. This expansion leads to a detachment force at the connection point between the busbar and the negative terminal of the cell. During random vibration tests, this connection point is subjected to a shear force in addition to the aforementioned detachment force. Both the detachment and shear forces increase the risk of failure of the connection structure between the busbar and the negative terminal of the cell, thus compromising the service life and safety of the battery module or battery pack. CONTENT OF THE REGISTRATION

[0004] In view of the shortcomings of the existing technology, the first objective of the present application is to provide a busbar assembly capable of absorbing the pull-off and shear forces at the connection point between the negative pole end of the cell and the negative pole section when the cell expands or vibrates, thereby effectively reducing the risk of failure of the connection structure between the negative pole section and the negative pole end of the cell.

[0005] First, this application provides a busbar assembly used for a cylindrical power battery module. The cylindrical power battery module comprises several cells, and the busbar assembly comprises a positive terminal strip, a negative terminal strip, a series strip, and a terminal strip, wherein: the terminal strip is arranged on a cylindrical power battery module, the terminal strip being configured to connect two adjacent cells in series in a first direction, and the terminal strip being configured to connect two adjacent cells in parallel in a second direction; the series strip being configured to connect two adjacent cylindrical power battery modules in series to form a battery group; the positive terminal strip being connected at the positive terminal end of the cell to a positive output end of a battery group;the negative terminal strip at the negative terminal end of the cell is connected to a negative output end of the battery group, and the parts where the terminal strip, the series strip and the negative terminal strip are each connected to the negative terminal end of the corresponding cell are defined as negative terminal sections, wherein at least one separating groove is provided on the negative terminal section, which serves to divide the negative terminal section in a second direction into at least two separating parts, each separating part being connected to the negative terminal end of the cell.

[0006] Secondly, the present application provides a battery module comprising the aforementioned busbar assembly. This battery module offers a high level of safety. Thirdly, this application provides a battery pack comprising the aforementioned battery module. This battery pack is highly safe and has a long service life.

[0007] The individual, separate parts of this application are each connected to the negative terminals of the corresponding cells. Compared to a structure where the negative terminal section is welded as a whole to the negative terminal of the cell, this configuration allows for an effective reduction of welding stresses. When the cell expands or vibrates, the separate parts deform to absorb the detachment and shear forces present at the connection point between the negative terminal of the cell and the negative terminal section. This effectively reduces the risk of failure of the connection structure between the negative terminal section and the negative terminal of the cell, thus improving the service life and safety of the cylindrical power battery module or battery pack. BRIEF DESCRIPTION OF THE DRAWING Fig. Figure 1 shows a schematic representation of the three-dimensional structure of a battery group according to an embodiment of the present application. Fig. Figure 2 shows a schematic top view of the structure of a battery group according to an embodiment of the present application. Fig. Figure 3 shows a schematic representation of the explosion structure of a battery group according to an embodiment of the present application. Fig. Figure 4 shows a partially enlarged schematic representation of the structure at location A in Fig. 3. Fig. Figure 5 shows a partially enlarged schematic representation of the structure at position B in Fig. 3. Fig. Figure 6 shows a schematic top view of the structure of a terminal strip according to an embodiment of the present application.

[0008] Reference numerals: 10, cylindrical power battery module; 100, cell; 210, positive terminal strip; 220, terminal strip; 221, single sheet; 221a, first positive terminal section; 221b, first negative terminal section; 222, first disconnect section; 223, overflow hole; 230, series strip; 230a, negative electrode module; 230b, positive electrode module; 231, second negative terminal section; 2311, second disconnect section; 232, parallel negative terminal body; 233, second groove; 240, negative terminal strip; 241, third negative terminal section; 2411, third disconnect section; 242, strip body; 250, second thermal fuse; 260, first thermal fuse; 270, disconnect groove; 271, first rounding; 272, second rounding; 280, arch; 290, first extension section; 291, first depression. DETAILED DESCRIPTION

[0009] In the description of this application, it should be noted that the alignment and positioning positions represented by the terms "top," "bottom," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," and "outside" refer to the alignment and positioning positions shown in the drawings. This information is provided solely for the sake of clarity and simplification of the description and is not intended to prescribe or imply any particular orientation, construction, or operation of the device or component in question. Therefore, it should not be construed as a limitation of this application.

[0010] In the description of this application, unless expressly stated or limited otherwise, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or suggesting a relative significance; the term "several" refers to two or more; the term "and / or" includes any combination and all combinations of one or more of the listed items. In particular, the mention of "this" or "one" item also refers to one possible item among several such items.

[0011] Unless otherwise defined, all technical and scientific terms in this application correspond to the usual understanding of persons skilled in the technical field of this application; the terms used in the description of this application serve only to describe specific embodiments and are not intended to limit the application; the terms "including" and "comprising" and their variations in the description, the claims, and the above drawings are intended to signify non-exclusive inclusion. Furthermore, in the description of this application, it should be understood that the directional terms mentioned, such as "top," "bottom," "inside," and "outside," are described from the perspective of the accompanying drawings and should not be interpreted as limiting specific embodiments.It is also important to understand that in context, when an element or feature is associated with another element (one or more) as "above", "below", "inside" or "outside", this can mean not only a direct connection, but also an indirect connection via intermediate components.

[0012] In one embodiment, the angle between the extension direction of the separating groove and the first direction is ±45°.

[0013] In one embodiment, a rounded section is arranged at the upper corner of the separating groove.

[0014] In one embodiment, the width of the separating groove is 0.5 mm to 5 mm.

[0015] In one embodiment, the width of the separating groove is 1 mm to 3 mm.

[0016] In one embodiment, the terminal strip comprises at least two individual sheets arranged along the second direction, wherein two adjacent individual sheets are connected by a first temperature fuse.

[0017] In one embodiment, the part of the single sheet that is connected to the positive terminal end of the corresponding cell is defined as the first positive terminal section, and the part of the single sheet that is connected to the negative terminal end of the corresponding cell is defined as the first negative terminal section, and the end of the first temperature fuse is connected to the first positive terminal section.

[0018] In one embodiment, a first extension section is provided on both sides of two adjacent individual sheets arranged in a second direction, wherein the first extension section is provided at the first positive pole section; a first recess is provided on the first extension section, which is designed to receive the first temperature fuse.

[0019] In one embodiment, the first negative terminal section is provided with a bulge that projects away from the cell. The separation groove arranged on the terminal strip extends to this bulge.

[0020] In one embodiment, the upper surface of the bulge is parallel to the plane in which the first negative pole section is located, with the shortest distance between the two being 1 mm to 2 mm. In another embodiment, an overflow hole is arranged throughout the first positive pole section.

[0021] In one embodiment, the series strip comprises an interconnected positive electrode module and a negative electrode module, wherein the negative electrode module is connected to the negative terminal end of the cell at an output end of the cylindrical power battery module, and the positive electrode module is connected to a positive terminal end of the cell at an input end of the other cylindrical power battery module; and the positive electrode module and the negative electrode module are connected by a second thermal fuse.

[0022] Please refer to the Fig. 1 to 6. A busbar assembly used for a cylindrical power battery module 10 comprising several cells 100 includes a positive terminal strip 210, a negative terminal strip 240, a series strip 230, and a connection strip 220, wherein: the connection strip 220 is arranged on a cylindrical power battery module 10 and serves to connect two adjacent cells 100 in series in the first direction and to connect two adjacent cells 100 in parallel in the second direction; the series strip 230 serves to connect two adjacent cylindrical power battery modules 10 in series to form a battery group; the positive terminal strip 210 is connected to the positive terminal end of the cell 100 at the positive output end of the battery group; the negative terminal strip 240 is connected to the negative terminal end of the cell 100 at the negative output end of the battery group.And the parts where the terminal strip 220, the series strip 230 and the negative terminal strip 240 are each connected to the negative terminal end of the corresponding cell 100 are defined as negative terminal sections, wherein at least one separating groove 270 is provided on the negative terminal section, which serves to divide the negative terminal section in a second direction into at least two separating parts, each separating part being connected to the negative terminal end of the cell 100.

[0023] In this embodiment, it is preferred that a separation groove 270 is arranged on the negative pole section, extending in the first direction and dividing the negative pole section into two identical separation parts in the second direction. During use, each separation part is connected to the negative pole end of the corresponding cell 100. The structure that divides the negative pole section into two separation parts improves the deformability of the negative pole section. Compared to the structure in which the negative pole section is welded as a whole to the negative pole end of the cell 100, this arrangement can effectively reduce the welding stress.When the cell 100 expands or vibrates, the separating parts deform to absorb the detachment forces and shear forces at the connection point between the negative terminal end of the cell 100 and the negative terminal section, effectively reducing the risk of failure of the connection structure between the negative terminal section and the negative terminal end of the cell 100, and increasing the service life and safety of the cylindrical power battery module 10 or battery pack.

[0024] Here, the negative pole section is evenly divided into two identical separating parts, giving both separating parts the same overflow area. On the one hand, this ensures that each separating part has a similar deformation capacity, meaning that the different areas of the negative pole section are able to absorb the separation and shear forces evenly. At the same time, the structure of the separating groove 270, which runs along the first direction, facilitates the machining of the separating groove 270.

[0025] In another embodiment, the direction of extension of the separating groove 270 runs parallel to the first direction, and the number of separating grooves 270 can be two or three, etc. Accordingly, two separating grooves 270 divide the negative pole section in the second direction into three sections, while three separating grooves 270 divide the negative pole section in the second direction into four sections. It should be noted that the number of separating grooves 270 can be determined as required, without imposing any specific restrictions here.

[0026] In other embodiments, the angle between the extension direction of the separating groove 270 and the first direction can optionally be in the range of ±45°. The preferred embodiment, in which the angle between the extension direction of the separating groove 270 and the first direction is 0°, is described in the Fig. 2 and Fig. Figure 6 is shown, but not explained further here. In this embodiment, two adjacent separating grooves 270 can be arranged parallel or non-parallel, as long as the negative pole section can be subdivided into several separating parts. It should be noted that the shapes of the individual separating parts can differ if the directions of extension of both adjacent separating grooves 270 are not parallel.

[0027] In this embodiment, the width of the separating groove 270 can optionally be between 0.5 mm and 5 mm. Furthermore, the width of the separating groove 270 is 1 mm to 3 mm.

[0028] As in Fig. As shown in Figure 6, the width of the separation groove 270 is preferably D1, where D1 is equal to 2 mm. In other embodiments, D1 can be 2.2 mm, 2.4 mm, or 2.6 mm. In this way, the separation groove 270 can not only achieve the preceding reduction of the welding stress in the negative pole section and the absorption of the peel and shear forces at the connection point between the negative pole end of cell 100 and the negative pole section, but also meet the requirements for current flow and temperature rise of the busbar assembly.

[0029] In this embodiment, a rounding is provided at the upper corner of the separating groove 270.

[0030] Specifically, a first radius 271 is arranged at the inner upper corner of the parting groove 270, with a radius of 0.5 mm. The first radius 271 serves to reduce the stress concentration at the inner upper corner of the parting groove 270 and to prevent the parting groove 270 from tearing at the inner upper corner during deformation of the parting piece. A second radius 272 is arranged at the outer upper corner of the parting groove 270. The radius of the second radius 272 is 2 mm. The second radius 272 serves to prevent the negative terminal end of the cell 100 from being scraped during assembly of the parting piece.

[0031] In this embodiment, examples of how in Fig. Figure 2 shows two cylindrical power battery modules 10 connected in series by a series strip 230 to form a battery group. Specifically, the first direction is the X-direction, as shown in Fig. 2 and Fig. 3 shown, and the second direction is the Y direction, as in Fig. 2 and Fig. Figure 3 shows that, to simplify the description, in a cylindrical power battery module 10, a series of cells 100 along the first direction is defined as a battery row. Therefore, the cylindrical power battery module 10 provided in this embodiment comprises two battery rows arranged along the second direction.The connection point where terminal strip 220 is connected to the negative terminal end of cell 100 is defined as the first negative terminal section 221b, and the connection point where terminal strip 220 is connected to the positive terminal end of cell 100 is defined as the first positive terminal section 221a; the connection point where series strip 230 is connected to the negative terminal end of cell 100 is defined as the second negative terminal section 231, and the connection point where series strip 230 is connected to the positive terminal end of cell 100 is defined as the second positive terminal section; the connection point where negative terminal strip 240 is connected to the negative terminal end of cell 100 is defined as the third negative terminal section 241.In this embodiment, at least one separating groove 270 is used to divide the first negative pole section 221b into at least two first separating parts 222; at least one separating groove 270 is used to divide the second negative pole section 231 into at least two second separating parts 2311; at least one separating groove 270 is used to divide the third negative pole section 241 into at least two third separating parts 2411.

[0032] Specifically, the terminal strip 220 comprises at least two individual plates 221 arranged along the second direction, with adjacent two individual plates 221 being connected to each other by a first thermal fuse 260. In this embodiment, the terminal strip 220 comprises two individual plates 221 arranged along the second direction, corresponding to the two battery rows of the cylindrical power battery module 10 arranged along the second direction. In the event of a short circuit inside or outside the cylindrical power battery module 10, the first thermal fuse 260 can precisely and rapidly interrupt the circuit, thereby improving the safety of the cylindrical power battery module 10 or the battery pack.

[0033] As in Fig. 4 and Fig. As shown in Figure 6, in this embodiment the connection point between the single sheet 221 and the positive terminal end of the associated cell 100 is the aforementioned first positive terminal section 221a, and the connection point between the single sheet 221 and the negative terminal end of the associated cell 100 is the aforementioned first negative terminal section 221b. The end region of the first thermal fuse 260 is connected to the first positive terminal section 221a. Furthermore, a first extension section 290 is provided on both sides near two adjacent single sheets 221, which are arranged in the second direction, wherein the first extension section 290 is provided at the first positive terminal section 221a, and wherein the first extension section 290 is provided with a first groove 291, which serves to receive the first thermal fuse 260.The first groove 291 facilitates, on the one hand, the mounting and soldering of the first thermal fuse 260 to the first extension section 290, and on the other hand, the embedding of the first thermal fuse 260 in the first groove 290 allows a reduction in the structural thickness of the first thermal fuse 260 in the longitudinal direction, i.e. in the Z-direction, as in . Fig. 3 shown to prevent components such as cooling plates on the top side of the busbar assembly from displacing or damaging the first thermal fuse 260.

[0034] In this embodiment, as in the Fig. 4 and Fig. As shown in Figure 6, the first negative terminal section 221b is provided with a bulge 280 that curves away from the cell 100. The separating groove 270, which is arranged on the terminal strip 220, extends to the bulge 280. Here, the first negative terminal section 221b, the first positive terminal section 221a, and the first extension section 290 are formed in one piece. More precisely, the single sheet 221 is manufactured by stamping. In actual production, there are deviations in the external dimensions of the individual cells 100; therefore, after the cells 100 are assembled in the housing (not shown), the negative terminal ends of the individual cells 100 point in the Z-direction according to Fig. 3 exhibits certain height differences. The curvature 280 provides a certain degree of deformation clearance for the first negative pole section 221b or the individual first separating parts 222 in the Z-direction. In combination with the separating groove 270, this allows the deformation clearance of the individual first separating parts 222, i.e., the curvature 280, to be extended more easily in order to compensate for the deviations in the dimensions in the Z-direction of the cells 100.

[0035] In this embodiment, the upper surface of the bulge 280 is parallel to the plane in which the first negative pole section 221b is located, with the shortest distance between the two being 1 mm to 2 mm. Preferably, the shortest distance between the upper surface of the bulge 280 and the plane in which the first negative pole section 221b is located is 1 mm. In other embodiments, the shortest distance between the upper surface of the bulge 280 and the plane in which the first negative pole section 221b is located can be 1.1 mm, 1.2 mm, or 1.3 mm. This configuration allows, on the one hand, the deformation clearance requirement of the terminal strip 220 to be met in the Z-direction and, on the other hand, prevents the terminal strip 220 from being too large in the Z-direction.

[0036] In this embodiment, as in the Fig. 3 and Fig. As shown in Figure 5, the series assembly 230 comprises an interconnected positive electrode module 230b and a negative electrode module 230a, wherein the negative electrode module 230a is connected to the negative terminal of a cell 100 at an output end of a cylindrical power battery module 10, and the positive electrode module 230b is connected to the positive terminal of a cell 100 at an input end of another cylindrical power battery module 10. Specifically, the positive electrode module 230b and the negative electrode module 230a are connected via a second thermal fuse 250. In the event of an internal or external short circuit of the battery assembly, the second thermal fuse 250 blows to interrupt the circuit, thereby ensuring the safety of the battery assembly or battery pack.

[0037] Furthermore, the negative electrode module 230a comprises a parallel negative pole body 232 on which the aforementioned second negative pole section 231 is mounted. Both the negative electrode module 230a and the positive electrode module 230b are equipped with a second groove 233, which is intended for receiving a second thermal fuse 250. As in Fig. As shown in Figure 3, the negative terminal strip 240 comprises a strip body 242 on which the aforementioned third negative terminal section 241 is mounted. In this embodiment, the strip body 242 extends along the second direction, and two third negative terminal sections 241 are mounted on the side of the strip body 242 facing the cell 100 and are arranged such that they are each connected to the negative terminal ends of two cells 100 at the negative output end of the battery group. Here, the strip body 242 functions as the negative output end of the battery group.

[0038] In this embodiment, an overflow hole 223 is arranged throughout the first positive terminal section 221a. In this embodiment, the overflow hole 223 communicates with the gap between the first positive terminal section 221a and the negative terminal end of the associated cell 100. When foam is filled between the cells 100, the excess foam expands along the Z-direction and escapes through the overflow hole 223, thereby reducing the force exerted on the series strip 230 to expel the foam from the cells 100, thus providing a high degree of safety.

[0039] This embodiment also provides a battery module, in particular the cylindrical power battery module 10, as shown in Fig. Figure 2 shows the busbar assembly described above. This battery module offers a high level of safety.

[0040] This embodiment also provides a battery pack comprising the previously described battery module or a battery group produced by connecting the serial strips 230 using the previously described battery module. This battery pack offers high safety and a long service life.

Claims

[1] Busbar assembly used for a cylindrical power battery module (10), wherein the cylindrical power battery module (10) comprises several cells (100), and the busbar assembly comprises a positive terminal strip (210), a negative terminal strip (240), a series strip (230) and a terminal strip (220), wherein: the terminal strip (220) is arranged on a cylindrical power battery module (10), wherein the terminal strip (220) is designed to connect two adjacent cells (100) in series in a first direction, and the terminal strip (220) is designed to connect two adjacent cells (100) in parallel in a second direction; the series strip (230) is arranged such that it connects two adjacent cylindrical power battery modules (10) in series to form a battery group; the positive terminal strip (210) is connected to the positive terminal end of the cell (100) at a positive output end of a battery group; the negative terminal strip (240) is connected to the negative terminal end of the cell (100) at a negative output end of the battery group, and the parts where the terminal strip (220), the series strip (230) and the negative terminal strip (240) are each connected to the negative terminal end of the corresponding cell (100) are defined as negative terminal sections, wherein at least one separating groove (270) is provided on the negative terminal section, which serves to divide the negative terminal section in a second direction into at least two separating parts, each separating part being connected to the negative terminal end of the cell (100). [2] Busbar assembly according to claim 1, wherein the angle between the extension direction of the separation groove (270) and the first direction is in the range of ±45°. [3] Busbar assembly according to claim 1, wherein a rounding is formed at the upper corner of the separating groove (270). [4] Busbar assembly according to one of claims 1-3, wherein the width of the separating groove (270) is 0.5 mm to 5 mm. [5] Busbar assembly according to claim 4, wherein the width of the separating groove (270) is 1 mm to 3 mm. [6] Busbar assembly according to one of claims 1-3, wherein the terminal strip (220) comprises at least two individual sheets (221) arranged along the second direction, wherein two adjacent individual sheets (221) are connected to each other by a first thermal fuse (260). [7] Busbar assembly according to claim 6, wherein the connection point where the single sheet (221) is connected to the positive terminal end of the corresponding cell (100) is defined as the first positive terminal section (221a), the connection point where the single sheet (221) is connected to the negative terminal end of the corresponding cell (100) is defined as the first negative terminal section (221b), and the end region of the first thermal fuse (260) is connected to the first positive terminal section (221a). [8] Busbar assembly according to claim 7, wherein a first extension section (290) is provided on both sides in close proximity to each other of two individual sheets (221) which are arranged in the second direction, wherein the first extension section (290) is provided at the first positive terminal section (221a); ​​wherein the first extension section (290) is provided with a first groove (291) which serves to receive the first thermal fuse (260). [9] Busbar assembly according to claim 7, wherein the first negative pole section (221b) is provided with a bulge (280) that protrudes away from the cell (100), wherein the separating groove (270) arranged on the terminal strip (220) extends to the bulge (280). [10] Busbar assembly according to claim 9, wherein the top of the bulge (280) is parallel to the plane in which the first negative pole section (221b) is located, and the shortest distance between the top of the bulge (280) and the plane in which the first negative pole section (221b) is located is 1 mm to 2 mm. [11] Busbar assembly according to claim 7, wherein the first positive pole section (221a) is continuously provided with an overflow hole (223). [12] Busbar assembly according to claim 1, wherein the series strip (230) comprises an interconnected positive electrode module (230b) and negative electrode module (230a), where the negative electrode module (230a) is connected to a negative terminal end of the cell (100) at an output end of a cylindrical power battery module (10), while the positive electrode module (230b) is connected to a positive terminal end of the cell (100) at an input end of another cylindrical power battery module (10); the positive electrode module (230b) and the negative electrode module (230a) are connected via a second thermal fuse (250). [13] Battery module comprising a busbar assembly according to any one of claims 1-12. [14] Battery pack comprising the battery module according to claim 13.

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