CN218039729U - Utmost point ear structure, electric core pole piece and lithium cell - Google Patents

Abstract

The utility model discloses a utmost point ear structure, electric core pole piece and lithium cell, distribute along pole piece length direction including a plurality of utmost point ears, utmost point ear divide into the N section along the pole piece to wherein utmost point ear stretches out pole piece length shortest section utmost point ear length and is the basis, all the other sections along keeping away from shortest section direction, utmost point ear stretches out pole piece length and increases in proper order, the shortest section in, the length that utmost point ear stretches out the pole piece equals. One end of the pole piece is provided with a non-pole lug section. After the battery core pole piece is wound, the pole lugs are welded together and are connected to the connecting piece together. The utility model discloses a predominant use is when utmost point ear twines into electric core, and utmost point ear demonstrates the echelonment because of the size difference, and after utmost point ear through ultrasonic bonding, every utmost point ear all links together, and utmost point ear top is parallel mutually, can not demonstrate the echelonment and arrange, also can not appear utmost point ear shelter from the connection piece and lap and carry out laser welding, reduces the welding degree of difficulty, produces the bad problem of welding when avoiding connection piece and apron to carry out laser welding simultaneously.

Description

A tab structure, battery pole piece and lithium battery

technical field

The utility model relates to the technical field of lithium batteries, in particular to a tab structure, battery pole pieces and lithium batteries.

Background technique

Lithium battery (LithiumCell) refers to the most basic electrochemical unit containing lithium (including metal lithium, lithium alloy and lithium ion, lithium polymer) in the electrochemical system. Due to the high working voltage, long cycle life and safety performance of lithium ion battery Good features, so it is widely used in all walks of life. With the increasingly difficult environmental problems, people are paying more and more attention to energy conservation and emission reduction. Therefore, the development of new energy vehicles is an inevitable choice for my country's economic transformation under the pressure of low-carbon emission reduction. As the "heart" of new energy vehicles, the lithium battery industry has developed rapidly under the influence of the country's strong support for the development of new energy industries and national policies. The battery is divided into positive and negative poles. The tabs are the metal conductors that lead the positive and negative poles out of the battery. Generally speaking, the ears of the positive and negative poles of the battery are the contact points when charging and discharging, and the size of the tabs and The quantity affects the capacity and rate of the lithium battery.

With the development of the lithium battery industry, the low rate and low capacity problems of ordinary lithium batteries need to be solved urgently. At this stage, various manufacturers are successively developing lithium batteries with large capacity and high rate. However, as the capacity of lithium batteries increases, the volume of lithium batteries also gradually increases. In order to ensure that the cells can be welded together, the size and number of tabs are also increased. In the assembly process of lithium batteries, it is often necessary to ultrasonically weld the tabs and connecting pieces first, and then weld the connecting pieces to the cover plate by laser, and the increase in the size and number of tabs will lead to Arranged in a ladder shape, it affects the laser welding of the connecting piece and the cover plate, resulting in poor welding, which seriously affects the safety performance of the battery. In the prior art, if the tab size is shortened or the number of tabs is reduced, the distance between the tab and the connecting piece will be insufficient and the requirement of high magnification cannot be met.

Contents of the invention

1. The technical problems to be solved by the utility model

In order to realize the large capacity and high rate performance of the lithium battery in the existing technology, the size and quantity of the tabs are continuously increased, resulting in a stepped arrangement of the tabs after ultrasonic welding, which affects the laser welding of the connecting piece and the cover plate Leading to poor welding and seriously affecting the safety performance of lithium batteries, the utility model provides a tab structure, battery pole piece and lithium battery, which can realize the increase in the size and number of tabs after ultrasonic welding of tabs Finally, the lug structure will not be arranged in steps, and the problem of poor welding will not occur when the connecting piece and the cover plate are laser welded.

2. Technical solution

In order to achieve the above object, the technical solution provided by the utility model is:

A tab structure, a plurality of tabs are distributed along the length direction of the pole piece, and the tabs are divided into N sections along the pole piece, based on the length of the shortest section of the tab extending out from the pole piece, and the rest of the sections are along the length of the pole piece. In the direction away from the shortest section, the length of the lug protruding from the pole piece increases in turn.

Further, in the shortest section, the lengths of the tabs protruding from the pole pieces are equal.

Further, the tab is divided into a first tab segment, a second tab segment and a third tab segment, and the three segments are sequentially connected along the length direction of the pole piece.

Further, in the second lug segment, the length of the lug protruding from the pole piece is smaller than that of the first lug segment and the third lug segment.

Further, in the second lug segment, the lugs protrude from the pole pieces to an equal length.

Further, an ultrasonic welding zone is set on the tab, and after the tab is welded, the ultrasonic welding zone is located on the same plane.

The utility model also provides a pole piece of the electric core, the surface of the pole piece is provided with a coating area.

Further, a non-pole ear segment is provided at one end of the pole piece.

Further, the first lug segment, the second lug segment and the third lug segment are all arranged on the coating area.

The utility model also provides a lithium battery. After the pole piece of the battery core is wound, the tabs are welded together and connected to the connecting piece together.

3. Beneficial effects

Adopting the technical solution provided by the utility model, compared with the existing known technology, has the following beneficial effects:

(1) In the tab structure provided by the utility model, the tab is based on the shortest section of the tab length, and the length of the other tabs in the direction away from the shortest section of the tab increases sequentially. It is realized that when the tabs are wound into a battery core, the tabs present a stepped shape due to different sizes. After the tabs are ultrasonically welded, each tab is connected together, and the tops of the tabs are parallel to each other, there will be no stepped arrangement, and there will be no tabs blocking the connecting piece and the cover plate for laser welding , to reduce the difficulty of welding.

(2) A battery pole piece provided by the utility model is provided with non-pole ear segments, the first pole ear segment, the second pole ear segment, and the third pole ear segment. For the above-mentioned tabs, when multiple tabs and pole pieces are wound into a battery core, after the tabs on the tab section are ultrasonically welded and connected to the connection piece, the distance between the top of the tab and the laser welding area of the connection piece is relatively small. It can effectively avoid the problem of poor welding when the connecting piece and the cover plate are laser welded.

(3) In the lithium battery provided by the utility model, the lithium battery will not have a small capacity and a low rate due to shortening the tab size or reducing the number of tabs. On the contrary, when the size and number of tabs are continuously increasing, the lithium battery has large capacity, high rate, and good safety performance.

Description of drawings

Fig. 1 is a schematic diagram of the lug structure of the improved front pole piece;

Fig. 2 is a schematic diagram of the new tab structure of the improved pole piece of the utility model;

Fig. 3 is the left view of the electric core after the tab structure of the utility model is wound;

Fig. 4 is the isometric drawing of the electric core after the tab structure of the utility model is wound;

Fig. 5 is a left view of the utility model after the tab of the wound battery cell is welded to the connecting piece;

Fig. 6 is an orthographic triaxial view of the utility model after welding the lug of the winding cell and the connecting piece.

Explanation of the labels in the schematic diagram: 100, battery core; 1, coating area; 10, first side; 11, non-pole ear section; 12, first pole ear section; 13, second pole ear section; 14, third pole Ear segment; 20, tab; 201, ultrasonic welding area; 21, first tab; 22, second tab; 23, third tab; 24, first imaginary line; 25, second imaginary line; 30 , connecting piece; 301, laser welding zone.

detailed description

In order to further understand the content of the utility model, the utility model is described in detail in conjunction with the accompanying drawings and embodiments.

Example

As shown in FIG. 1 , in order to improve the tab structure of the front pole piece, a plurality of tabs 20 are distributed along the length direction of the pole piece, and each tab 20 has the same length. In the actual production process, if you want to manufacture a lithium battery with a large capacity and a high rate, you need to continuously increase the size and quantity of the tabs 20, but this will make the tabs 20 appear in a stepped arrangement after ultrasonic welding. As a result, when the subsequent connecting piece and the cover plate are laser welded, there will be a problem of poor welding, which will also affect the performance and safety performance of the lithium battery.

Specifically in this embodiment, a battery pole piece is provided with a coating area 1 on its surface. One end of the pole piece is provided with a non-pole ear segment 11 , a first pole ear segment 12 , a second pole ear segment 13 and a third pole ear segment 14 .

As shown in Figure 2, in the tab structure provided by this embodiment, a plurality of tabs 20 are distributed along the length direction of the pole piece, and the tabs 20 are divided into N sections along the pole piece, wherein the tabs 20 extend out of the length of the pole piece Based on the length of the tab 20 of the shortest section, the length of the tab 20 protruding from the pole piece of the other sections increases sequentially along the direction away from the shortest section. It should be noted that, in the shortest section where the tabs 20 protrude from the pole piece, the lengths that the tabs 20 protrude from the pole piece are equal.

In this embodiment, the non-pole ear segment 11 is set as the starting end, which is connected to the first ear segment 12 in sequence, the first ear segment 12 is connected to the second ear segment 13 in sequence, and the second ear segment 13 is connected to the third ear segment. The tab segments 14 are connected in sequence. A first-sized tab 21 is provided on the first tab segment 12 , a second-sized tab 22 is provided on the second tab segment 13 , and a third-sized tab 23 is provided on the third tab segment 14 . The sizes of the lugs on the first lug segment 12 , the second lug segment 13 and the third lug segment 14 are all different. Wherein, each lug 20 on the second-sized lug 22 on the second lug segment 13 has the same length, and the first-sized lug 21 on the first lug segment 12 and the lug 21 on the third lug segment 14 have the same length. Each tab 20 in the third-sized tab 23 is based on the second-sized tab 22 on the second tab segment 12 , along the direction away from the second-sized tab 22 on the second tab segment 12 , increasing in length. This can realize that when the tab 20 is wound into a battery core, the tab 20 presents a stepped shape due to different sizes.

As shown in Figures 5 and 6, the tab 20 is located on the top of the battery cell 100, and the connecting piece 30 has a structure such as a U-shape or an opening curve or similar shape, and there is an area at the end of the connecting piece 30 that is not open. Laser welding zone 301 .

After the plurality of tabs 20 on the tab segment are wound, due to the different sizes of the tabs 20 on each tab segment, they will present a stepped shape when wound into the battery core 100 . As shown in FIG. 3 and FIG. 4 , for a battery pole piece provided in this embodiment, when a plurality of tab pole pieces are wound into a battery cell 100 , the first imaginary line 24 of the multiple tab pole pieces is The reference line is constantly approaching the first imaginary line 24 , the lengths of the tabs 20 at the first imaginary line 24 are equal, and this level is the second imaginary line 25 . When the tabs 20 extend to both ends, the lengths of the tabs 20 at both ends are gradually higher than the second imaginary line 25 , so that the tabs and pole pieces will have inclined surfaces during the winding process.

After the tabs 20 are ultrasonically welded, they are located in the same plane as the ultrasonic welding area 201, and each tab 20 is bent due to the different welding positions, so that the top of each tab 20 is aligned, and there will be no abnormalities after the tabs 20 are welded. Arranged in steps. Therefore, the tab 20 will not block the connecting piece 30 and the cover plate for laser welding, which can effectively reduce the difficulty of welding.

After the tabs 20 are ultrasonically welded, with the first imaginary line 24 as the reference, each tab 20 is constantly approaching the first imaginary line 24. Since the distance between the bottom of each tab 20 and the first imaginary line 24 is continuously increasing, When the tab 20 is close to the first imaginary line 24, the length of the formed inclined surface also needs to be increased accordingly. At this time, in order to keep the top height of each tab 20 the same as the second imaginary line 25, it is necessary to increase each The length of the tab 20, therefore, the present embodiment is based on the second imaginary line 25, the farther the tab 20 from the first imaginary line 24, the greater the height above the second imaginary line 25, thereby completing each pole The tops of the ears 20 are aligned.

The ultrasonic welding area 201 of the tab 20 is connected to one end of the connecting piece 30 . When the tab 20 is in the welding state, it is connected to one end of the connecting piece 30 , and then the tab 20 and the connecting piece 30 are ultrasonically welded at the ultrasonic welding zone 201 . At this time, the top of the lug 20 is far away from the laser welding area 301 of the connecting piece 30, which will not interfere with the laser welding between the connecting piece 30 and the cover plate, effectively avoiding the problem of poor laser welding of the cover plate.

This embodiment also provides a lithium battery. By adopting the above-mentioned tab structure and battery pole pieces, it can be realized that when the size and number of tabs 20 increase continuously, the capacity of the lithium battery increases, the rate increases, and it can ensure Safety performance of lithium batteries.

The above schematically describes the utility model and its implementation, which is not restrictive, and what is shown in the accompanying drawings is only one implementation of the utility model, and the actual structure is not limited thereto. Therefore, if a person of ordinary skill in the art is inspired by it, and without departing from the purpose of the invention of the utility model, without creatively designing a structural mode and an embodiment similar to the technical solution, it shall belong to the utility model. protected range.

Claims (10)

1. The utility model provides a utmost point ear structure, a plurality of utmost point ears (20) distribute along pole piece length direction, its characterized in that, utmost point ear (20) divide into the N section along the pole piece to wherein utmost point ear (20) stretch out pole piece length shortest section utmost point ear (20) length and be the basis, all the other sections are along keeping away from shortest section direction, utmost point ear (20) stretch out pole piece length and increase in proper order.

2. A tab construction according to claim 1, wherein the tabs (20) extend from the pole pieces in the shortest sections by equal lengths.

3. The pole lug structure as claimed in claim 2, wherein the pole lug (20) is divided into a first pole lug section (12), a second pole lug section (13) and a third pole lug section (14), and the three sections are connected in sequence along the length direction of the pole pieces.

4. A tab structure according to claim 3, wherein the tab (20) of the second tab section (13) extends beyond the pole piece by a length less than the first tab section (12) and the third tab section (14).

5. A tab structure as claimed in claim 4, wherein the tabs (20) of the second tab section (13) extend out of the tab section by the same length.

6. A tab structure as claimed in any one of claims 1 to 5, wherein the tab (20) is provided with an ultrasonic welding region (201), and after the tab (20) is welded, the ultrasonic welding region (201) is located on the same plane.

7. A battery cell pole piece comprising a tab structure according to any one of claims 1 to 6, wherein the surface of the pole piece is provided with a coating region (1).

8. The cell pole piece according to claim 7, characterized in that one end of the pole piece is provided with a tab-free section (11).

9. The cell pole piece according to claim 8, characterized in that the first tab section (12), the second tab section (13) and the third tab section (14) are disposed on the coating region (1).

10. A lithium battery comprising a cell pole piece according to any of claims 7 to 9, wherein after winding the cell pole piece, the tabs (20) are welded together and connected together to the connecting tab (30).

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