CN214898779U

CN214898779U - Power Battery

Info

Publication number: CN214898779U
Application number: CN202120387134.9U
Authority: CN
Inventors: 王俊; 王洪伟; 渠雁晓; 杨恒峰; 崔红艳
Original assignee: Kunshan Bao Innovative Energy Technology Co Ltd
Current assignee: Shenzhen Guohong New Energy Technology Co ltd
Priority date: 2021-02-22
Filing date: 2021-02-22
Publication date: 2021-11-26
Anticipated expiration: 2031-02-22

Abstract

The utility model relates to a power battery. The power battery comprises at least two groups of battery core pole groups which are stacked along the thickness direction. Each group of cell pole group comprises a first naked cell, a second naked cell, a positive connecting piece and a negative connecting piece. Through welding positive connecting piece subregion twice, can make the anodal intercommunication of these two naked electric cores to when welding at every turn, only need with the corresponding region of positive connecting piece with the anodal utmost point ear welding of the single naked electric core that corresponds can. In the process of welding the second areas of the positive connecting pieces of the different groups of battery cell pole groups with each other, the positive pole lugs do not need to be welded again. Therefore, the anode connecting sheet is welded in three areas and welded for three times, so that the number of layers of the anode lug during single welding can be reduced, and the risks of insufficient welding, welding penetration and welding crack of the anode lug can be reduced. In a similar way, the negative electrode connecting piece is welded in three areas and welded for three times, so that the number of layers of the negative electrode lug during single welding can be reduced.

Description

Power battery

Technical Field

The utility model relates to a power battery technical field, especially power battery.

Background

The lithium ion battery has the advantages of small self-discharge, high energy density and the like, so that the lithium ion battery becomes a power battery which is widely applied. The power battery is internally provided with a naked electric core. Naked electric core includes positive plate and the negative pole piece of many pairs of range upon range of setting in proper order. Each positive plate has a positive tab and the negative plate has a negative tab. With the development of battery technology, higher and higher requirements are put on the energy density and the space utilization rate of the battery. In order to increase the energy density of the battery, the bare cell is made larger and larger. Correspondingly, the number of layers of the positive and negative pole pieces of the bare cell is more and more, and thus the number of layers of the positive and negative pole ears is more and more. The utmost point ear of the naked electric core of difference is usually with same connection piece welding together to naked electric core of difference is connected. However, the number of layers of the tab of the bare cell is too many, so that the problems of insufficient welding, welding penetration, tab welding crack and the like easily occur in the welding of the tab and the connecting sheet, and the performance of the battery is easily influenced.

SUMMERY OF THE UTILITY MODEL

Based on this, it is necessary to provide a power battery that can reduce utmost point ear rosin joint, weld and wear, weld and split the risk to lead to the easy rosin joint, weld and wear, utmost point ear welding of utmost point ear and connection piece to the problem because the utmost point ear number of piles of naked electric core is too much.

The embodiment of the application provides a power battery, which comprises at least two groups of battery cell pole groups, wherein the at least two groups of battery cell pole groups are stacked along a first direction, and the first direction is the thickness direction of each group of battery cell pole groups;

each group of the cell pole groups comprises:

the first bare cell is provided with a first positive electrode lug and a first negative electrode lug;

the second bare cell is provided with a second positive electrode lug and a second negative electrode lug, the second bare cell and the first bare cell are arranged along a second direction, and the second direction is perpendicular to the first direction;

the positive electrode connecting piece is provided with a first area, a second area and a third area, the first area is welded with the first positive electrode lug, and the third area is welded with the second positive electrode lug;

the negative electrode connecting sheet is provided with a fourth area, a fifth area and a sixth area, the fourth area is welded with the first negative electrode tab, and the sixth area is welded with the second negative electrode tab;

the second regions of the positive connection pieces of the different groups of the cell pole groups are welded to each other, and the fifth regions of the negative connection pieces of the different groups of the cell pole groups are welded to each other.

The power battery comprises at least two battery cell pole groups which are stacked in the thickness direction. The first region of the positive connection piece of every group battery cell utmost point group welds with first anodal utmost point ear, and the third region welds with the anodal utmost point ear of second to can communicate each other with the positive pole of the first naked electric core in every group battery cell utmost point group and the anodal of the naked electric core of second. The second areas of the different groups of the battery cell pole groups are welded with each other, so that the anodes of the different groups of the battery cell pole groups can be communicated with each other. That is to say, with two naked electric cores in every electric core utmost point group carry out the in-process of connecting, through welding positive connection piece subregion twice, can make the anodal intercommunication of these two naked electric cores to when welding at every turn, only need with the corresponding region of positive connection piece with the anodal utmost point ear welding of single naked electric core that corresponds can, thereby weld twice through dividing the region with positive connection piece, the number of piles of anodal utmost point ear when having reduced welding at every turn. Furthermore, in the process of welding the second areas of the positive connecting pieces of the different groups of battery cell pole groups with each other, the positive pole lug does not need to be welded again. Therefore, in the assembly process of the power battery, the anode connecting sheet is welded in three areas and welded for three times, the number of layers of the anode tab during single welding can be reduced, and the risks of insufficient welding, penetration welding and cracking of the anode tab can be reduced.

In the same way, the in-process of connecting two naked electric cores in every electric core polar group is through welding negative pole connection piece subregion twice, can make the negative pole intercommunication of these two naked electric cores to when welding at every turn, only need with the corresponding region of negative pole connection piece with the welding of the negative pole utmost point ear of the single naked electric core that corresponds can, thereby weld twice through dividing the region with negative pole connection piece, the number of piles of negative pole utmost point ear when having reduced welding at every turn. Furthermore, in the process of welding the fifth areas of the negative connecting sheets of the different groups of battery cell pole groups with each other, the negative pole tabs do not need to be welded again. Therefore, in the assembly process of the power battery, the negative electrode connecting piece is welded in three areas and welded for three times, the number of layers of the negative electrode lug during single welding can be reduced, and the risks of insufficient welding, penetration welding and welding cracking of the negative electrode lug can be reduced.

In one embodiment, the junction of the second area and the first area of the positive connecting piece forms a step structure, and the junction of the second area and the third area of the positive connecting piece forms a step structure;

the connecting position of the fifth area and the fourth area of the negative connecting sheet forms a step structure, and the connecting position of the fifth area and the sixth area of the negative connecting sheet forms a step structure.

In an embodiment, the positive connection tab is located between the first bare cell and the second bare cell, and the first area, the second area, and the third area are sequentially arranged along the second direction;

the negative connecting piece is located between the first naked electric core and the second naked electric core, and the fourth area, the fifth area and the sixth area are sequentially arranged along the second direction.

In an embodiment, the second direction is a width direction of the first bare cell and the second bare cell; or the second direction is the width length direction of the first naked electric core and the second naked electric core.

In an embodiment, the power battery further includes a cover plate, a positive electrode post of the cover plate is welded to the second area of the positive electrode connecting piece, and a negative electrode post of the cover plate is welded to the fifth area of the negative electrode connecting piece.

In one embodiment, each of the cell electrode groups further includes a positive electrode protection sheet and a negative electrode protection sheet;

the side, opposite to the first area of the corresponding positive connecting sheet, of the first positive electrode lug is welded with the positive protective sheet;

the side, opposite to the third area of the corresponding positive connecting sheet, of the second positive electrode lug is welded with the positive protective sheet;

the side, opposite to the fourth area of the corresponding negative electrode connecting sheet, of the first negative electrode lug is welded with the negative electrode protection sheet;

and the side, opposite to the corresponding sixth area of the negative electrode connecting sheet, of the second negative electrode lug is welded with the negative electrode protection sheet.

In an embodiment, the at least two sets of cell pole groups include a first cell pole group and a second cell pole group which are arranged in a stacked manner.

In one embodiment, in the first direction, the second region of the positive connection tab of the first cell pole group is closer to the positive connection tab of the second cell pole group than the first region and the third region;

along the first direction, the second region of the positive connection sheet of the second cell pole group is closer to the positive connection sheet of the first cell pole group than the first region and the third region;

in the first direction, the fifth region of the negative connection tab of the first cell pole group is closer to the negative connection tab of the second cell pole group than the fourth region and the sixth region;

along the first direction, the fifth area of the negative connection sheet of the second cell pole group is closer to the negative connection sheet of the first cell pole group than the fourth area and the sixth area.

In an embodiment, the at least two sets of cell pole groups further include a third cell pole group; the third cell pole group is arranged between the first cell pole group and the second cell pole group in a stacked mode.

In one embodiment, the positive connection tab of the first cell pole group is located on one side of the first positive tab of the first cell pole group, which is close to the second cell pole group;

the positive connecting piece of the second cell pole group is positioned on one side, close to the first cell pole group, of the first positive electrode lug of the second cell pole group;

the negative connecting sheet of the first cell pole group is positioned on one side, close to the second cell pole group, of the first negative tab of the first cell pole group;

the negative electrode connecting piece of the second battery cell pole group is positioned at one side of the first negative electrode tab of the second battery cell pole group close to the first battery cell pole group.

Drawings

Fig. 1 is a schematic structural diagram of a power battery of a first embodiment;

fig. 2 is a schematic structural diagram of the first cell pole group in fig. 1;

fig. 3 is a schematic structural diagram of a second cell pole group in fig. 1;

FIG. 4 is a schematic structural view of the positive connection tab of FIG. 1;

FIG. 5 is a schematic view of the structure of the positive protective sheet of FIG. 2;

FIG. 6 is a schematic structural diagram of a cover plate of the power battery in FIG. 1;

FIG. 7 is a schematic structural view of a positive electrode tab in another embodiment;

fig. 8 is a schematic structural diagram of a power battery of the second embodiment;

fig. 9 is a schematic structural diagram of the first cell pole group in fig. 8;

fig. 10 is a schematic structural diagram of a second cell pole group in fig. 8;

fig. 11 is a schematic structural diagram of the third cell pole group in fig. 8.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" 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, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Referring to fig. 1, a power battery 100 is provided in a first embodiment of the present application. The power battery 100 includes at least two sets of cell pole groups 110. At least two sets of cell pole group 110 are along the range upon range of setting of first direction. The first direction is a thickness direction of each cell electrode group 110.

Specifically, as shown in fig. 2 and fig. 3, in the present embodiment, the power battery 100 includes two sets of cell electrode groups 110. The two cell electrode groups 110 are a first cell electrode group 110a and a second cell electrode group 110b, respectively. The first cell pole group 110a and the second cell pole group 110b are stacked in the thickness direction of the two.

Each set of cell pole groups 110 includes: first naked electric core 111, the naked electric core 112 of second, anodal connection piece 113 and negative pole connection piece 114. The first bare cell 111 has a first positive electrode tab 1111 and a first negative electrode tab 1112. The second bare cell 112 has a second positive electrode tab 1121 and a second negative electrode tab 1122. Naked electric core 112 of second arranges along the second direction with first naked electric core 111, the first direction of second direction perpendicular to.

Specifically, as shown in fig. 1 to fig. 3, in this embodiment, the second direction is the length direction of the first bare cell 111 and the second bare cell 112. Naked electric core 112 of second and first naked electric core 111 are arranged along the length direction interval of the two. The first positive electrode tab 1111 and the first negative electrode tab 1112 are arranged at intervals along the width direction of the first bare cell 111. The second positive electrode tab 1121 and the second negative electrode tab 1122 are arranged at intervals along the width direction of the second bare cell 112. The first positive electrode tab 1111 is disposed opposite to the second positive electrode tab 1121. The first anode tab 1112 is disposed opposite to the second anode tab 1122.

Positive connection piece 113 and negative connection piece 114 all lie in between first naked electric core 111 and the naked electric core 112 of second. The positive connection plate 113 is used to connect the first positive tab 1111 and the second positive tab 1121, so as to communicate the positive electrode of the first bare cell 110a with the positive electrode of the second bare cell 110 b. The negative electrode connecting piece 114 is used to connect the first negative electrode tab 1112 and the second negative electrode tab 1122, so as to communicate the negative electrode of the first bare cell 110a with the negative electrode of the second bare cell 110 b.

Referring to fig. 4 in conjunction with fig. 1 to 3, the positive electrode tab 113 has a first region 1131, a second region 1132, and a third region 1133, and the first region 1131, the second region 1132, and the third region 1133 are sequentially arranged along the second direction. The first region 1131 of the positive electrode connecting sheet 113 and the first positive electrode tab 1111 can be welded by ultrasonic welding, and the third region 1133 of the positive electrode connecting sheet 113 and the second positive electrode tab 1121 can be welded by ultrasonic welding. The second region 1132 is located between the first region 1131 and the third region 1133.

The negative electrode tab 114 has a fourth region (not shown), a fifth region (not shown), and a sixth region (not shown), and the fourth region, the fifth region, and the sixth region are arranged in this order in the second direction. The fourth region of the negative electrode connecting piece 114 and the first negative electrode tab 1112 may be welded by ultrasonic welding, and the sixth region of the negative electrode connecting piece 114 and the second negative electrode tab 1122 may be welded by ultrasonic welding. The fifth region is located between the fourth region and the sixth region.

The second regions 1132 of the positive connecting pieces 113 of the different groups of cell pole groups 110 are welded to each other, and the fifth regions of the negative connecting pieces 114 of the different groups of cell pole groups 110 are welded to each other.

Specifically, when the power battery 100 is assembled, the second region 1132 of the positive connecting tab 113a of the first cell pole group 110a and the second region 1132 of the positive connecting tab 113b of the second cell pole group 110b may be welded by laser welding, and the fifth region of the negative connecting tab 114a of the first cell pole group 110a and the fifth region of the negative connecting tab 114b of the second cell pole group 110b may be welded by laser welding, so that the first cell pole group 110a and the second cell pole group 110b can be electrically connected.

The power battery 100 includes at least two battery cell pole groups 110 stacked in the thickness direction. The first region 1131 of the positive connection sheet 113 of each group of cell pole groups 110 is welded with the first positive electrode tab 1111, and the third region 1133 is welded with the second positive electrode tab 1121, so that the positive electrode of the first naked cell 111 and the positive electrode of the second naked cell 112 in each group of cell pole groups 110 can be mutually communicated. The second regions 1332 of the different groups of cell pole groups 110 are welded to each other, so that the positive electrodes of the different groups of cell pole groups 110 can be connected to each other. That is to say, with two naked electric cores in every electric core utmost point group 110 the in-process of connecting, through weld twice with anodal connection piece 113 subregion, can make the anodal intercommunication of these two naked electric cores, and when welding at every turn, only need with anodal connection piece 113 the corresponding region with the anodal utmost point ear welding of the single naked electric core of correspondence can, thereby weld twice through carrying out anodal connection piece 113 subregion, the number of piles of anodal utmost point ear when having reduced welding at every turn. Further, in the process of welding the second regions 1332 of the positive connection pieces 113 of the different cell electrode groups 110 to each other, the positive electrode tabs do not need to be welded again. Therefore, in the assembly process of the power battery, the positive connecting sheet 113 is welded in three areas and welded for three times, so that the number of layers of the positive pole lug during single welding can be reduced, and the risks of insufficient welding, penetration welding and cracking of the positive pole lug can be reduced.

In the same way, the in-process of connecting two naked electric cores in every electric core polar group 110, through weld twice with negative pole connection piece 114 subregion, can make the negative pole intercommunication of these two naked electric cores, and when welding at every turn, only need with the corresponding region of negative pole connection piece 114 with the welding of the negative pole utmost point ear of the single naked electric core that corresponds can, thereby weld twice through dividing the region with negative pole connection piece 114, the number of piles of negative pole utmost point ear when having reduced welding at every turn. Further, in the process of welding the fifth areas of the negative connecting pieces 114 of the different groups of cell pole groups 110 to each other, the negative pole tabs do not need to be welded again. Therefore, in the assembly process of the power battery, the negative electrode connecting sheet 114 is welded in three areas and welded for three times, so that the number of layers of the negative electrode lug during single welding can be reduced, and the risks of insufficient welding, penetration welding and cracking of the negative electrode lug can be reduced.

Specifically, as shown in fig. 4, one end of the second region 1132 of the positive electrode connecting piece 113 is provided with a first groove 101, and the other end is provided with a second groove 102, so that both ends of the positive electrode connecting piece 113 are easily distinguished, and thus the mounting direction error of the positive electrode connecting piece 113 can be prevented.

Further, a chamfer 1134 is formed at a corner of an edge of the first region 1131 of the positive electrode tab 113, so that the first region 1131 and the third region 1133 of the positive electrode tab 113 are easily distinguished, and thus the mounting direction error of the positive electrode tab 113 can be further prevented.

Similarly, the fifth region of the negative connecting plate 114 may also be provided with a corresponding first groove and a corresponding second groove, and the edge of the fourth region of the negative connecting plate 114 may also be provided with a corresponding chamfer to prevent the negative connecting plate 114 from being installed in a wrong direction.

Referring to fig. 2 and fig. 3, in an embodiment, each cell pole group 110 further includes a positive protective sheet 115 and a negative protective sheet 116.

Specifically, each cell pole group 110 includes two positive protective sheets 115 and two negative protective sheets 116.

A positive protective sheet 115 is welded to a side of the first positive electrode tab 1111 facing away from the first region 1131 of the positive electrode connecting sheet 113. A positive electrode protection sheet 115 is welded to the side of the second positive electrode tab 1121 facing away from the third region 1133 of the positive electrode connection sheet 113.

Specifically, in fig. 2 and 3, the positive electrode connecting tab 113 is located below the first positive electrode tab 1111 and the second positive electrode tab 1121, a positive electrode protection sheet 115 is welded above the first positive electrode tab 1111, and a positive electrode protection sheet 115 is welded above the second positive electrode tab 1121. The positive electrode protective sheet 115 can protect the first positive electrode tab 1111 by locating the first positive electrode tab 1111 between the first region 1131 of the positive electrode tab 113 and the corresponding positive electrode protective sheet 115. Similarly, the positive electrode protective sheet 115 can protect the second positive electrode tab 1121 by locating the second positive electrode tab 1121 between the third region 1133 of the positive electrode connection sheet 113 and the corresponding positive electrode protective sheet 115.

The side of the fourth region of the first negative electrode tab 1112 facing away from the negative electrode connecting piece 114 is welded with the negative electrode protective sheet 116. A negative protective sheet 116 is welded to a side of the sixth region of the second negative electrode tab 1122 facing away from the negative electrode connecting sheet 114.

Specifically, in fig. 2 and 3, the negative electrode connecting piece 114 is located below the first negative electrode tab 1112 and the second negative electrode tab 1122, one negative electrode protection sheet 116 is welded above the first negative electrode tab 1112, and one negative electrode protection sheet 116 is welded above the second negative electrode tab 1122. The anode protective sheet 116 can protect the first anode tab 1112 by locating the first anode tab 1112 between the fourth region of the anode connecting sheet 114 and the corresponding anode protective sheet 116. Similarly, the second negative electrode tab 1122 can be protected by the negative electrode protection sheet 116 by positioning the second negative electrode tab 1122 between the sixth region of the negative electrode connecting sheet 114 and the corresponding negative electrode protection sheet 116.

Referring to fig. 5, in an embodiment, one end of the positive electrode protection sheet 115 is provided with a first chamfer 1151, and the other end is provided with a second chamfer 1152. The first chamfer 1151 and the second chamfer 1152 have different sizes, so that the first chamfer 1151 and the second chamfer 1152 are asymmetrical, and thus both ends of the positive protective sheet 115 are easily distinguished, so that the positive protective sheet 115 is prevented from being mounted in a wrong direction.

Likewise, the negative electrode protection sheet 116 may be provided with respective first and second chamfers, thereby easily distinguishing both ends of the negative electrode protection sheet 116 so as to prevent the negative electrode protection sheet 116 from being installed in a wrong direction.

The positive electrode protection sheet 115 and the negative electrode protection sheet 116 may be respectively formed by folding, so that edges of the positive electrode protection sheet 115 and the negative electrode protection sheet 116 respectively form rounded corners, and the corresponding tabs are not easily damaged.

As described above, in fig. 2, the positive connection tab 113a of the first cell pole group 110a is located below the corresponding first and second

positive tabs

1111a and 1121a, and the negative connection tab 114a is located below the corresponding first and second

negative tabs

1112a and 1122 a. In fig. 3, the positive connection tab 113b of the second cell pole group 110b is located below the corresponding first positive tab 1111b and second positive tab 1121b, and the negative connection tab 114b is located below the corresponding first negative tab 1112b and second negative tab 1122 b.

However, in another embodiment, the positive electrode connecting tab 113a of the first cell group 110a is located at a side of the first positive electrode tab 1111a of the first cell group 110a close to the first positive electrode tab 1111b of the second cell group 110b, and the positive electrode connecting tab 113b of the second cell group 110b is located at a side of the first positive electrode tab 1111b of the second cell group 110b close to the first positive electrode tab 1111a of the first cell group 110 a. That is, the positive connecting tab 113a of the first cell group 110a may be located below the corresponding first positive tab 1111a and the second positive tab 1121a, and the positive connecting tab 113b of the second cell group 110b may be located above the corresponding first positive tab 1111b and the second positive tab 1121b, so that the positive connecting tab 113a of the first cell group 110a is located close to the positive connecting tab 113b of the second cell group 110b, and the second region 1132 of the positive connecting tab 113a of the first cell group 110a is connected to the second region 1132 of the positive connecting tab 113b of the second cell group 110b conveniently, easily and reliably. Similarly, the negative connection tab 114a of the first cell group 110a is located on a side of the first negative tab 1112a of the first cell group 110a close to the first negative tab 1112b of the second cell group 110 b. Negative connection tab 114b of second cell pole group 110b is located on a side of first negative tab 1112b of second cell pole group 110b that is adjacent to first negative tab 1112a of first cell pole group 110 a. That is, the negative connection tab 114a of the first cell pole group 110a may be located below the corresponding first negative tab 1112a and second negative tab 1122a, and the negative connection tab 114b of the second cell pole group 110b may be located above the corresponding first negative tab 1112b and second negative tab 1122b, so that the negative connection tab 114a of the first cell pole group 110a is close to the negative connection tab 114b of the second cell pole group 110b, and the fifth area of the negative connection tab 114a of the first cell pole group 110a is conveniently welded to the fifth area of the negative connection tab 114b of the second cell pole group 110b, and the fifth area is easily and reliably connected.

Referring to fig. 6, in an embodiment, the power battery 100 further includes a cover plate 130. The positive electrode post 131 of the cap plate 130 and the second region 1132 of the positive electrode connecting piece 113 may be welded by laser welding, and the negative electrode post 132 of the cap plate 130 and the fifth region of the negative electrode connecting piece 114 may be welded by laser welding.

Referring to fig. 7, in another embodiment, a step structure 117 is formed at a connection portion of the second region 1132 and the first region 1131 of the positive electrode connecting sheet 113, and a step structure 117 is formed at a connection portion of the second region 1132 and the third region 1133 of the positive electrode connecting sheet 113, so that, along a thickness direction of the positive electrode connecting sheet 113, the first region 1131 and the third region 1133 respectively form a height difference with the second region 1132, and the first region 1131, the second region 1132 and the third region 1133 can be further distinguished. The first region 1131 and the third region 1133 are welded to the corresponding positive electrode tabs by ultrasonic welding. The second regions 1132 of the different groups of cell electrode groups 110 are welded together by laser welding. By separating the first region 1131, the second region 1132, and the third region 1133, the ultrasonic welding region can be separated from the laser welding region, and the influence of deformation on the laser welding region in the ultrasonic welding process can be reduced.

Similarly, a step structure 117 is formed at the joint of the fifth area and the fourth area of the negative connecting piece 114, and a step structure 117 is formed at the joint of the fifth area and the sixth area of the negative connecting piece 114, so that the fourth area and the sixth area form a height difference with the fifth area along the thickness direction of the negative connecting piece 114, and the fourth area, the fifth area and the sixth area can be distinguished. The fourth area and the sixth area are welded with corresponding negative pole tabs in an ultrasonic welding mode. The fifth areas of the different groups of cell electrode groups 110 are welded together by laser welding. By separating the fourth region, the fifth region, and the sixth region, the ultrasonic welding region can be separated from the laser welding region, and the influence of deformation on the laser welding region in the ultrasonic welding process can be reduced.

In one embodiment, in the first direction, the second region of the positive electrode tab 113a of the first cell electrode group 110a is closer to the positive electrode tab 113b of the second cell electrode group 110b than the first region and the third region. In the first direction, the second region of the positive electrode connecting piece 113b of the second cell electrode group 110b is closer to the positive electrode connecting piece 113a of the first cell electrode group 110a than the first region and the third region.

In the first direction, the fifth region of the negative connection tab 114a of the first cell pole group 110a is closer to the negative connection tab 114b of the second cell pole group 110b than the fourth region and the sixth region. In the first direction, the fifth region of the negative connection tab 114b of the second cell pole group 110b is closer to the negative connection tab 114a of the first cell pole group 110a than the fourth region and the sixth region.

Specifically, in this embodiment, the first cell pole group 110a is located above the second cell pole group 110b, and the second cell pole group 110b is located below the first cell pole group 110 a. Therefore, the height of the second area of the positive electrode connecting piece 113a of the first cell electrode group 110a is lower than the heights of the first area and the third area, so that the second area of the positive electrode connecting piece 113a of the first cell electrode group 110a is closer to the positive electrode connecting piece 113b of the second cell electrode group 110c, and the second area of the positive electrode connecting piece 113a of the first cell electrode group 110a is convenient to weld with the second area of the second cell electrode group 110 b. Specifically, since the connection point of the second region of the positive electrode connecting piece 113a of the first cell electrode group 210a and the first region and the connection point of the third region form a stepped structure, respectively, the height of the second region of the positive electrode connecting piece 113a of the first cell electrode group 110a can be made lower than the height of the first region and the third region by the stepped structure.

Similarly, the second region of the positive electrode connecting piece 113b of the second cell electrode group 110b, the connection part with the first region, and the connection part with the third region form a step structure, so that the second region of the positive electrode connecting piece 113b of the second cell electrode group 110b is higher than the first region and the third region, and the second region of the positive electrode connecting piece 113b of the second cell electrode group 110b is conveniently welded with the second region of the positive electrode connecting piece 113a of the first cell electrode group 110 a.

Similarly, the fifth area of the negative connection tab 114a of the first cell pole group 110a is lower than the fourth area and the sixth area by forming a step structure at the connection between the fifth area and the fourth area and at the connection between the fifth area and the sixth area of the negative connection tab 114a of the first cell pole group 110a, so that the fifth area of the negative connection tab 114a of the first cell pole group 110a is conveniently welded to the fifth area of the negative connection tab 114b of the second cell pole group 110 b.

Similarly, the fifth area of the negative connection tab 114b of the second cell pole group 110b can be higher than the fourth area and the sixth area by forming a step structure at the connection between the fifth area and the fourth area and at the connection between the fifth area and the sixth area of the negative connection tab 114b of the second cell pole group 110b, so that the fifth area of the negative connection tab 114b of the second cell pole group 110b can be conveniently welded to the fifth area of the negative connection tab 114a of the first cell pole group 110 a.

Referring to fig. 8, a power battery 200 is provided in a second embodiment of the present application. The basic structure of the power battery 200 of the second embodiment is substantially the same as that of the power battery 100 of the first embodiment, and the description thereof is omitted. The following description focuses on the differences in the basic structure of the power cell 200 of the second embodiment from the power cell 100 of the first embodiment.

Referring to fig. 8 to 11, the power battery 200 includes three sets of cell electrode groups 210, namely a first cell electrode group 210a, a second cell electrode group 210b, and a third cell electrode group 210 c. The first cell pole group 210a and the second cell pole group 210b in the second embodiment are basically the same as the first cell pole group 110a and the second cell pole group 110b in the first embodiment, and are not described again here.

The third cell pole group 210c is disposed between the first cell pole group 210a and the second cell pole group 210b, so as to form a stacked structure of three layers of cell pole groups, thereby improving the capacity of the power battery 200. Referring to fig. 11, the third cell group 210c also includes a first bare cell 211c, a second bare cell 212c, a positive connection piece 213c, and a negative connection piece 214 c. The first region of the positive connection piece 213c is welded to the first positive tab 2111c of the first bare cell 211c, and the third region is welded to the second positive tab 2121c of the second bare cell 211 c. The fourth area of the negative connecting piece 214c is welded with the first negative tab 2112c of the first bare cell 211c, and the sixth area is welded with the second negative tab 2122c of the second bare cell 211 c.

The second region of the positive connection tab 213c of the third cell pole group 210c is welded to the second region of the positive connection tab 213a of the first cell pole group 210a and the second region of the positive connection tab 213b of the second cell pole group 210b, so that the positive electrodes of the three cell pole groups 210 are connected to each other. A fifth region of the negative connection tab 214c of the third cell pole group 210c is welded to a fifth region of the negative connection tab 214a of the first cell pole group 210a and a fifth region of the negative connection tab 214b of the second cell pole group 210b, so that the cathodes of the three cell pole groups 210 are communicated.

In one embodiment, the second region of the positive connection tab 213a of the first cell pole group 210a is closer to the positive connection tab 213c of the third cell pole group 210c than the first region and the third region along the first direction. In the first direction, the second region of the positive electrode connection tab 213b of the second cell pole group 210b is closer to the positive electrode connection tab 213c of the third cell pole group 210c than the first region and the third region.

In the first direction, the fifth region of the negative connection tab 214a of the first cell pole group 210a is closer to the negative connection tab 214c of the third cell pole group 210c than the fourth region and the sixth region. In the first direction, the fifth region of the negative connection tab 214b of the second cell pole group 210b is closer to the negative connection tab 214c of the third cell pole group 210c than the fourth region and the sixth region.

Specifically, in the present embodiment, the first cell pole group 210a is located above the third cell pole group 210c, and the second cell pole group 210b is located below the third cell pole group 210 c. It can be seen that the height of the second region of the positive connection tab 213a of the first cell pole group 210a is lower than the heights of the first region and the third region, so that the second region of the positive connection tab 213a of the first cell pole group 210a is closer to the positive connection tab 213c of the third cell pole group 210c, and the second region of the positive connection tab 213a of the first cell pole group 210a is more easily welded to the second region of the third cell pole group 210 c. Specifically, since the connection of the second region of the positive electrode connection piece 213a of the first cell electrode group 210a with the first region and the connection of the third region form a stepped structure, respectively, the height of the second region of the positive electrode connection piece 213a of the first cell electrode group 210a can be made lower than the heights of the first region and the third region by the stepped structure.

Similarly, the second region of the positive connection piece 213b of the second cell pole group 210b can be higher than the first region and the third region by forming a step structure at the connection point of the second region of the positive connection piece 213b of the second cell pole group 210b and the first region and the connection point of the third region, so that the second region of the positive connection piece 213b of the second cell pole group 210b and the second region of the positive connection piece 213c of the third cell pole group 210c can be welded conveniently.

Similarly, by forming the stepped structure at the connection point of the fifth area and the fourth area of the negative connection tab 214a of the first cell pole group 210a and at the connection point of the sixth area, the fifth area of the negative connection tab 214a of the first cell pole group 210a can be lower than the fourth area and the sixth area, so that the fifth area of the negative connection tab 214a of the first cell pole group 210a can be conveniently welded to the fifth area of the negative connection tab 214c of the third cell pole group 210 c.

Similarly, by forming the stepped structure at the connection point of the fifth area and the fourth area of the negative connection tab 214b of the second cell pole group 210b and at the connection point of the sixth area, the fifth area of the negative connection tab 214b of the second cell pole group 210b can be higher than the fourth area and the sixth area, so that the fifth area of the negative connection tab 214b of the second cell pole group 210b can be conveniently welded to the fifth area of the negative connection tab 214c of the third cell pole group 210 c.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A power battery, characterized in that it comprises at least two groups of cell electrode groups, and the at least two groups of cell electrode groups are stacked and arranged along a first direction, and the first direction is for each group of the cell electrode groups. thickness direction;

Each group of the cell electrode group includes:

The first bare cell has a first positive electrode tab and a first negative electrode tab;

The second bare cell has a second positive electrode tab and a second negative electrode tab, the second bare cell and the first bare cell are arranged in a second direction, and the second direction is perpendicular to the first bare cell one direction;

A positive electrode connecting piece, which has a first area, a second area and a third area, the first area is welded with the first positive electrode tab, and the third area is welded with the second positive electrode tab;

A negative electrode connecting piece has a fourth area, a fifth area and a sixth area, the fourth area is welded with the first negative electrode tab, and the sixth area is welded with the second negative electrode tab;

Wherein, the second regions of the positive connection pieces of different groups of the cell electrode groups are welded to each other, and the fifth regions of the negative electrode connection pieces of the different groups of the cell electrode groups are welded to each other.

2 . The power battery according to claim 1 , wherein the at least two groups of cell electrode groups comprise a first cell electrode group and a second cell electrode group arranged in layers. 3 .

3. The power battery according to claim 2, characterized in that,

Along the first direction, the second region of the positive connection piece of the first cell electrode group is closer to all the second cell electrode group than the first region and the third region. the positive connecting piece;

Along the first direction, the second region of the positive connection piece of the second cell electrode group is closer to all the first cell electrode group than the first region and the third region. the positive connecting piece;

Along the first direction, the fifth region of the negative electrode connecting piece of the first cell electrode group is closer to all the second cell electrode group than the fourth region and the sixth region. the negative connecting piece;

Along the first direction, the fifth region of the negative electrode connecting piece of the second cell electrode group is closer to all the first cell electrode group than the fourth region and the sixth region. the negative connection piece.

4 . The power battery according to claim 2 , wherein the at least two groups of cell electrode groups further comprise a third cell electrode group, and the third cell electrode group is stacked on the first cell electrode group. 5 . between the core electrode group and the second battery core electrode group.

5. The power battery according to claim 2, characterized in that,

The positive connection piece of the first cell electrode group is located on the side of the first positive electrode tab of the first cell electrode group close to the second cell electrode group;

The positive connection piece of the second cell electrode group is located on the side of the first positive electrode tab of the second cell electrode group close to the first cell electrode group;

The negative electrode connecting piece of the first cell electrode group is located on the side of the first negative electrode tab of the first cell electrode group close to the second cell electrode group;

The negative electrode connecting piece of the second cell electrode group is located on a side of the first negative electrode tab of the second cell electrode group close to the first cell electrode group.

6. The power battery according to claim 1, characterized in that,

A step structure is formed at the connection between the second region and the first region of the positive electrode connection piece, and a step structure is formed at the connection between the second region and the third region of the positive electrode connection piece;

The connection between the fifth region and the fourth region of the negative electrode connecting piece forms a stepped structure, and the connection between the fifth region and the sixth region of the negative electrode connecting piece forms a stepped structure.

7. The power battery according to claim 1, characterized in that,

The positive electrode connecting piece is located between the first bare cell and the second bare cell, and the first region, the second region and the third region are arranged in sequence along the second direction cloth;

The negative electrode connecting piece is located between the first bare cell and the second bare cell, and the fourth region, the fifth region and the sixth region are arranged in sequence along the second direction cloth.

8 . The power battery according to claim 1 , wherein the second direction is the width direction of the first bare cell and the second bare cell; or the second direction is the The width and length directions of the first bare cell and the second bare cell.

9 . The power battery according to claim 1 , further comprising a cover plate, the positive pole of the cover plate is welded to the second region of the positive electrode connecting piece, and the negative pole of the cover plate is welded. 10 . The pole post is welded with the fifth region of the negative electrode connecting piece.

10 . The power battery according to claim 1 , wherein each group of the battery cell electrode groups further comprises a positive electrode protection sheet and a negative electrode protection sheet; 10 .

The positive electrode protection sheet is welded on the side of the first positive electrode tab facing away from the first region of the corresponding positive electrode connecting sheet;

The positive electrode protection sheet is welded on the side of the second positive electrode tab facing away from the third region of the corresponding positive electrode connecting sheet;

The negative electrode protection sheet is welded on the side of the first negative electrode tab facing away from the fourth region of the corresponding negative electrode connecting sheet;

The negative electrode protection sheet is welded on the side of the second negative electrode tab facing away from the corresponding sixth region of the negative electrode connecting sheet.