CN112260020A

CN112260020A - Busbar, busbar subassembly, laminate polymer battery module and laminate polymer battery

Info

Publication number: CN112260020A
Application number: CN202011076161.0A
Authority: CN
Inventors: 徐冬; 伍智仁; 王会敏; 刘刚; 朱玉洲; 颜健
Original assignee: Soundon New Energy Technology Co Ltd
Current assignee: Soundon New Energy Technology Co Ltd
Priority date: 2020-10-10
Filing date: 2020-10-10
Publication date: 2021-01-22

Abstract

The invention provides a busbar, a busbar assembly, a soft-package battery module and a soft-package battery, wherein the busbar comprises a busbar body, a plurality of tab welding grooves for a power core tab to pass through are formed in the busbar body, the tab welding grooves correspond to the power core tabs one by one and are arranged side by side along a first direction; all be equipped with stress relief groove between every two adjacent utmost point ear welding grooves, such setting makes, the regional welding stress deformation region that forms between stress relief groove and the utmost point ear welding groove for welding stress that produces when electric core utmost point ear and busbar welding is effectively released, and the setting of stress relief groove simultaneously makes the heat that produces when welding can be very fast dispelled, reduces the heat altered shape that produces because heat gathering greatly, further elimination welding stress.

Description

Busbar, busbar subassembly, laminate polymer battery module and laminate polymer battery

Technical Field

The invention relates to the technical field of soft-package batteries, in particular to a bus bar, a bus bar assembly, a soft-package battery module and a soft-package battery.

Background

The soft package power battery has the advantages of good safety performance, light weight, large capacity, small internal resistance and the like, so that the soft package power battery is concerned by various large battery factories. However, the grouping structure design of the soft package battery core is relatively complex, and the structural influence factors to be considered are relatively more. The electric core in the soft-package battery module usually carries out series-parallel connection between the electric cores through the busbar. That is, the tab is contacted with the busbar by laser welding or other connection methods, and there are two methods commonly used at present, the first method: the tabs are welded on the bus bar through laser, so that the efficiency is high and the reliability is high; the second mode is as follows: the tab is welded in a top seam mode, namely the tab penetrates through a slit on a bus bar, energy is applied from the front by laser, and the tab is melted and filled into the slit of the bus bar for connection. However, in the two connection modes, the situation of weld joint cracking often occurs due to stress caused by expansion with heat and contraction with cold in the welding process.

Conventionally, chinese patent (application No.: CN201711408370.9) discloses a battery module comprising: a plurality of battery cells respectively including at least one tab; and a bus bar connected to the tabs to electrically connect the plurality of battery cells, the bus bar including a plate formed with a plurality of holes, the plate including protrusions formed around positions where the holes are formed, the plurality of tabs being inserted into at least some of the holes of the plurality of holes so that the plurality of tabs are electrically connected to each other, in which a bus bar tab projecting slit is formed in a punching-out manner to release welding stress, but this manner increases a manufacturing cost of a mold, and the protrusions occupy a space in a height direction, which is disadvantageous to other structural arrangements in the future.

Therefore, it is desirable to provide a novel bus bar structure which can save space, release welding stress and reduce the manufacturing cost of the mold.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a bus bar, a bus bar assembly, a soft package battery module and a soft package battery.

The invention provides a busbar which comprises a busbar body, wherein a plurality of tab welding grooves for a power core tab to penetrate through are formed in the busbar body, and the tab welding grooves correspond to the power core tabs one by one and are arranged side by side along a first direction; and a stress release groove is formed between every two adjacent tab welding grooves, and a welding stress deformation area is formed in the area between the stress release groove and the tab welding groove.

As a further improvement of the scheme, the distance between the groove edge of the stress relief groove and the groove edge of the tab welding groove is D1 or D2, D1 is less than or equal to 3t, and D2 is less than or equal to 3t, wherein t is the thickness of the bus bar body.

As a further improvement of the above scheme, the stress relief grooves are arranged at opposite corners of two sides of the tab welding groove in a staggered manner, and the length L4 of the stress relief grooves and the length L3 of the tab welding groove meet the requirement that L4 is not more than L3, at this time, the distance L1 between the notch of the stress relief groove and the edge of the busbar body needs to be greater than or equal to the distance L2 between the notch of the tab welding groove and the edge of the busbar body.

As a further improvement of the above scheme, the stress relief grooves are symmetrically arranged on two sides of the tab welding groove, and the length L4 of the stress relief grooves and the length L3 of the tab welding groove meet the condition that L4 is not less than L3, at this time, the distance L1 between the notch of the stress relief groove and the edge of the bus bar body is not less than L2.

As a further improvement of the scheme, the width of the notch of the tab welding groove is larger than 0.15-0.25 mm of the thickness of the battery core tab.

As a further improvement of the scheme, a V-shaped guide opening is formed in the back face of the tab welding groove, the depth of the V-shaped guide opening is H, H is larger than or equal to 1/2t, and t is the thickness of the busbar body.

As a further improvement of the scheme, the bus bar body is also provided with a plurality of riveting holes which are arranged between the adjacent tab welding grooves at intervals.

The invention also provides a bus bar assembly which comprises a bus bar support and at least one bus bar, wherein the bus bar and the bus bar support are riveted or buckled into a whole.

As a further improvement of the above solution, the bus bar and the bus bar support are integrated by hot melt riveting.

As a further improvement of the above scheme, the bus bar support is provided with support tab slots corresponding to the tab welding slots one to one so as to allow core tabs to pass through.

The invention also provides a soft package battery module, which comprises:

the above-described busbar assembly;

the battery cell comprises a plurality of battery cell units, a plurality of battery cell units and a plurality of battery cell units, wherein the battery cell units are arranged side by side along a first direction, and each battery cell unit comprises a battery cell main body and a battery cell lug, one end of each battery cell lug is connected with the battery cell main body;

and the battery cell lug is arranged in the lug welding groove of the busbar in a penetrating manner and is connected with the busbar.

As a further improvement of the above scheme, the height a of the battery cell tab exposed out of the tab welding groove is less than or equal to 1.5t, wherein t is the thickness of the busbar body.

The invention further provides a soft package battery, which comprises the soft package battery module and a frame assembly, wherein the soft package battery module is arranged inside the frame assembly, the frame assembly comprises an outer shell with an opening on the top surface, an upper cover covering the outer shell and a protective cover buckling the upper part of the busbar assembly, and the soft package battery module is arranged inside the outer shell.

As a further improvement of the scheme, the outer shell comprises a U-shaped outer frame and two module end plates, and the two module end plates are welded or riveted with the two ends of the U-shaped outer frame along the length direction of the U-shaped outer frame into a whole.

Due to the adoption of the technical scheme, the invention has the beneficial effects that:

the invention provides a busbar which comprises a busbar body, wherein a plurality of tab welding grooves for a power core tab to penetrate through are formed in the busbar body, and the tab welding grooves correspond to the power core tabs one by one and are arranged side by side along a first direction; all be equipped with stress relief groove between every two adjacent utmost point ear welding grooves, such setting makes, the regional welding stress deformation region that forms between stress relief groove and the utmost point ear welding groove for welding stress that produces when electric core utmost point ear and busbar welding is effectively released, and the setting of stress relief groove simultaneously makes the heat that produces when welding can be very fast dispelled, reduces the heat altered shape that produces because heat gathering greatly, further elimination welding stress. Compared with the bus bar related to the patent with the application number of CN201711408370.9, the bus bar in the patent adopts a mode of punching and protruding the periphery of the welding grooves of the lugs to release welding stress, the invention directly opens the stress release groove between the two adjacent welding grooves of the lugs, on one hand: compared with the bus bar with the application number of CN201711408370.9, the bus bar provided by the invention has the advantages that the structure of the die is simpler, which means that the cost of the die is reduced; on the other hand: the front side and the back side of the bus bar are flat and have no convex, so that the space in the thickness direction of the bus bar is saved, and other related structures are convenient to arrange.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic front view of a busbar according to the present invention;

FIG. 2 is a schematic rear view of a busbar according to the present invention;

FIG. 3 is a cross-sectional view B-B of FIG. 1;

FIG. 4 is a partial schematic view of FIG. 3;

FIG. 5 is a schematic front view of a busbar according to the present invention 2;

fig. 6 is a cross-sectional view of a pouch battery module of the present invention;

FIG. 7 is an enlarged view of a portion of FIG. 6;

fig. 8 is an exploded view of a pouch cell of the present invention;

FIG. 9 is a perspective view of the outer housing of the present invention;

reference numerals:

1. a bus bar; 11. a busbar body; 111. a tab welding groove; 112. a stress relief groove; 113. a V-shaped guide port; 114. riveting holes;

2. a bus bar assembly; 21. a busbar support; 211. a bracket polar lug groove;

3. a soft-package battery module; 31. a cell unit; 311. a cell main body; 312. a battery core tab;

4. a frame assembly; 41. an outer housing; 411. a U-shaped outer frame; 412. a module end plate; 42. an upper cover; 43. a protective cover.

Detailed Description

First, it should be understood by those skilled in the art that these embodiments are merely for explaining the technical principles of the present invention, and are not intended to limit the scope of the present invention. And can be adjusted as needed by those skilled in the art to suit particular applications.

Next, it should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "inside", "outside", and the like are based on the direction or positional relationship shown in the drawings, which are merely for convenience of description, and do not indicate or imply that a device or a member must have a specific orientation, be configured in a specific orientation, and operate, and thus, should not be construed as limiting the present invention.

Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "connected" and "connected" should be interpreted broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; the two components can be directly connected or indirectly connected through an intermediate medium, and the two components can be communicated with each other. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Furthermore, the terms "first", "second", "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", "third" may explicitly or implicitly include one or more of the features. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the description herein, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The invention is further described below with reference to the following figures and specific embodiments:

example 1:

referring to fig. 1 to 5, the present invention provides a bus bar, including a bus bar body 11, where the bus bar body 11 is provided with a plurality of tab welding grooves 111 for battery core tabs 312 to pass through, and the tab welding grooves 111 are in one-to-one correspondence with the battery core tabs 312 and are arranged side by side along a first direction; a stress relief groove 112 is formed between each two adjacent tab welding grooves 111. Such setting makes, the region between stress relief groove 112 and utmost point ear welding groove 111 forms welding stress deformation region, and the welding stress that produces when electric core utmost point ear 312 and busbar 1 welding is effectively released, can effectually avoid the fracture of welding seam, and the setting of stress relief groove 112 makes the heat that produces when welding can be very fast dispelled simultaneously, reduces the heat altered shape that produces because the heat gathering greatly, further elimination welding stress.

In the conventional embodiment, in order to release welding stress to punch and bulge the periphery of the tab welding groove 111, punching and bulging the periphery of the tab welding groove 111 means that a punching and bulging mold needs to be arranged, the tab welding groove 111 can be processed for a second time to form a line, the processing cost and the mold cost are increased, and after punching and bulging, the convex part occupies the space of the busbar 1 along the thickness direction, so that other related structures are not convenient to arrange; in the invention, the stress release groove 112 is directly formed between two adjacent tab welding grooves 111, and the stress release groove 112 only needs to be formed by punching or cutting together with the tab welding grooves 111 without extra punching and extra die cost; in addition, the front surface and the back surface of the bus bar 1 are flat and have no convex, so that the space in the thickness direction of the bus bar 1 is saved, and other related structures are convenient to arrange.

As a preferred embodiment, referring to fig. 1, in order to timely release the welding stress generated when the cell tab 312 is welded to the bus bar 1, the distance D1 or D2 between the groove edge of the stress release groove 112 and the groove edge of the tab welding groove 111 needs to satisfy D1 ≦ 3t, and D2 ≦ 3t, where t is the thickness of the bus bar body 11. Because the gap between the stress release groove 112 and the tab welding groove 111 is narrow, high temperature is instantaneously generated during welding to cause the thermal deformation of the narrow bus bar 1, so that the welding seam between the battery core tab 312 and the tab welding groove 111 is supplemented by a deformation material, and the redundant heat is timely dissipated through the stress release groove 112, thereby greatly reducing the welding stress and avoiding the phenomenon of welding seam cracking after welding.

As a preferred embodiment, referring to fig. 1 and 2, the stress relief grooves 112 are alternately arranged at opposite corners of both sides of the tab welding groove 111, and the length L4 of the stress relief groove 112 and the length L3 of the tab welding groove 111 satisfy L4 ≤ L3, at which time the distance L1 from the notch of the stress relief groove 112 to the edge of the busbar body 11 is greater than or equal to the distance L2 from the notch of the tab welding groove 111 to the edge of the busbar body 11. Stress release grooves 112 are arranged at opposite angle positions of two sides of a tab welding groove 111 in a staggered mode, so that heat in the middle of the bus bar 1 is concentrated faster, the middle position is just the position where the two stress release grooves 112 are overlapped, redundant heat can be rapidly dissipated to two sides, caused welding stress after thermal deformation can be timely eliminated through the stress release grooves 112 on two sides, and in addition, other functional structures are arranged more easily under the premise of guaranteeing current carrying of the bus bar 1 in a staggered and opposite angle distribution mode.

As a preferred embodiment, referring to fig. 5, the stress relief grooves 112 are symmetrically arranged on both sides of the tab welding groove 111, and the length L4 of the stress relief groove 112 and the length L3 of the tab welding groove 111 satisfy L4 ≧ L3, at which time, the distance L1 between the notch of the stress relief groove 112 and the edge of the busbar body 11 is less than or equal to the distance L2 between the notch of the tab welding groove 111 and the edge of the busbar body 11. Because stress release grooves 112 are symmetrically distributed, the length of the stress release grooves 112 is equal to or larger than that of tab welding grooves 111, a long narrow heat dissipation area is arranged between the two grooves, heat generated by tab welding can be timely conducted to the narrow heat dissipation area, heat dissipation is easier, and in addition, due to symmetrical distribution of two sides, production is unified, and the weight reduction effect is obvious.

It should be noted that the stress relief groove 112 in the present embodiment is a continuous kidney-shaped groove, but for a discontinuous kidney-shaped groove, or a plurality of stress relief holes arranged between two adjacent lug welding grooves 111, the stress relief holes also play a role in relieving stress, so as to reduce the probability of weld cracking, but such arrangement would increase the difficulty of processing and manufacturing.

As a preferred embodiment, in order to ensure that the cell tab 312 can conveniently pass through the tab welding groove 111 and reduce the welding workload, the width of the notch of the tab welding groove 111 is greater than 0.15-0.25 mm of the thickness of the cell tab 312.

2-4, the back of the tab welding groove 111 is provided with a V-shaped guide opening 113, the depth of the V-shaped guide opening 113 is H, H ≧ 1/2t, where t is the thickness of the busbar body 11. The arrangement of the V-shaped guide port 113 at the back of the tab welding groove 111 is convenient for leading in the cell tab 312; meanwhile, because an angle exists between the laser welding and the surface of the bus bar 1, an H-height structure is reserved for avoiding the direct laser damage to the battery cell during welding and the damage to the strength of the tab welding groove 111 and the melted tab during welding.

As a preferred embodiment, the busbar body 11 is further provided with a plurality of riveting holes 114, the riveting holes 114 are arranged at intervals between adjacent tab welding grooves 111, and the arrangement of the riveting holes 114 facilitates the connection of the busbar 1 and related components.

Example 2:

referring to fig. 8, the present invention further provides a bus bar assembly 2, which includes a bus bar support 21 and at least one bus bar 1, wherein the bus bar 1 and the bus bar support 21 are riveted or buckled into a whole. In the embodiment, the bus bar support 21 and the bus bar support 21 are fixed together by means of hot-melt riveting, the structure is firm, and the bus bar support 21 can strengthen the strength of the bus bar 1.

In a preferred embodiment, the bus bar bracket 21 is provided with bracket tab slots 211 corresponding to the tab welding slots 111 one to one, so that core tabs 312 can pass through.

Example 3:

referring to fig. 6 to 8, the present invention further provides a pouch battery module, including:

the above-described busbar assembly 2;

the battery cell comprises a plurality of battery cell units 31, wherein the battery cell units 31 are arranged side by side along a first direction, and each battery cell unit 31 comprises a battery cell main body 311 and a battery cell tab 312, one end of which is connected with the battery cell main body 311;

the cell tabs 312 penetrate through the tab welding grooves 111 of the busbar 1 and are connected with the busbar 1 in a welding manner.

As a further improvement of the above scheme, the height a of the battery cell tab 312 exposed out of the tab welding groove 111 is less than 1.5 times of the thickness t of the busbar 1, so that the excessive heat generated by welding can be taken away, and the occurrence of weld cracking is better avoided. When the height a of the battery cell tab 312 extending out of the upper surface of the busbar 1 is more than or equal to 1.5t, the redundant tab needs to be cut off.

Example 4:

referring to fig. 8, the invention further provides a pouch battery, which includes the pouch battery module 3 and a frame assembly 4, the pouch battery module 3 is arranged inside the frame assembly 4, the frame assembly 4 includes an outer casing 41 with an opening on the top surface, an upper cover 42 covering the outer casing 41, and a protective cover 43 covering the upper portion of the busbar assembly 2, and the pouch battery module 3 is arranged inside the outer casing 41.

As a preferred embodiment, referring to fig. 8 and 9, the outer case 41 includes a U-shaped outer frame 411 and two module end plates 412, and the two module end plates 412 are welded or riveted to both ends of the U-shaped outer frame 411 in the length direction thereof, respectively. Referring to fig. 9, when the U-shaped outer frame 411 and the two module end plates 412 are formed by riveting, the rivets pass through the two side plates of the U-shaped frame and are respectively driven into the riveting holes of the module end plates 412, so that the thickness of the two module end plates 412 is greater than that of the U-shaped outer frame 411 for accommodating the rivets, and the outer shell 41 is firmly and reliably connected.

The foregoing is a detailed description of the invention, and specific examples are used herein to explain the principles and implementations of the invention, the above description being merely intended to facilitate an understanding of the principles and core concepts of the invention. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims

1. A busbar is characterized by comprising a busbar body, wherein a plurality of tab welding grooves for a power core tab to penetrate through are formed in the busbar body, the tab welding grooves correspond to the power core tabs one by one and are arranged side by side along a first direction; and a stress release groove is formed between every two adjacent tab welding grooves, and a welding stress deformation area is formed in the area between the stress release groove and the tab welding groove.

2. The busbar according to claim 1, wherein the distance between the groove edge of the stress relief groove and the groove edge of the tab welding groove is D1 or D2, D1 is less than or equal to 3t, and D2 is less than or equal to 3t, wherein t is the thickness of the busbar body.

3. The busbar according to claim 1 or 2, wherein the stress relief grooves are alternately arranged at opposite corners of the tab welding groove, and the length L4 of the stress relief grooves and the length L3 of the tab welding groove satisfy L4 ≤ L3, at which time the distance L1 from the notch of the stress relief groove to the edge of the busbar body is greater than or equal to the distance L2 from the notch of the tab welding groove to the edge of the busbar body.

4. The busbar according to claim 1 or 2, wherein the stress relief grooves are symmetrically arranged on both sides of the tab welding groove, and the length L4 of the stress relief grooves and the length L3 of the tab welding groove satisfy L4 ≥ L3, and the distance L1 from the notch of the stress relief groove to the edge of the busbar body is less than or equal to the distance L2 from the notch of the tab welding groove to the edge of the busbar body.

5. The busbar according to claim 1 or 2, wherein the width of the notch of the tab welding groove is greater than 0.15 to 0.25mm of the thickness of the cell tab.

6. The busbar according to claim 1 or 2, wherein the back surface of the tab welding groove is provided with a V-shaped guide opening, the depth of the V-shaped guide opening is H, H is greater than or equal to 1/2t, and t is the thickness of the busbar body.

7. A busbar assembly comprising a busbar support and at least one busbar according to any one of claims 1 to 6, said busbar being riveted or snapped into one piece with the busbar support.

8. The utility model provides a laminate polymer battery module which characterized in that includes:

the busbar assembly of claim 7;

9. The soft package battery module according to claim 8, wherein the height a of the cell tab exposed out of the tab welding groove is not more than 1.5t, where t is the thickness of the busbar body.

10. The soft package battery is characterized by comprising the soft package battery module and a frame assembly according to claim 8 or 9, wherein the inside of the frame assembly is arranged in the soft package battery module, the frame assembly comprises an outer shell with an opening on the top surface, an upper cover for covering the outer shell and a protective cover for a buckling bus bar assembly, and the soft package battery module is arranged inside the outer shell.