CN116315479A - A method for flattening all tabs of a cylindrical battery - Google Patents

Abstract

The invention discloses a cylindrical battery full-tab flattening method, which comprises the following steps: s1: the pole lugs are rolled in a reciprocating way through a rubbing mechanism and are pre-rubbed and flattened, so that the pole lugs are gathered and pre-shaped; s2: and rubbing and shaping the pole lugs after gathering and pre-shaping through a rubbing and shaping mechanism, and forming regularly arranged electrolyte infiltration areas and current collecting disc welding areas. According to the invention, the pole lugs can be gathered and pre-shaped by the reciprocating rolling of the pole lugs through the rubbing mechanism, the arrangement mode of the pole lugs is optimized under the condition of ensuring the flatness and thickness of the rubbing plane, the rubbing mechanism is used for rubbing and shaping the gathered and pre-shaped pole lugs and forming regularly arranged electrolyte infiltration areas and collector plate welding areas, the metal scraps in the rubbing process are reduced, the poor short circuit is improved, and the welding qualification rate and electrolyte infiltration rate of the collector plates are improved through the main function distinction of different areas of the pole lugs.

Description

A method for flattening all tabs of a cylindrical battery

technical field

The invention relates to the technical field of flattening tabs of cylindrical batteries, and more particularly to a method for flattening all tabs of cylindrical batteries.

Background technique

The flattening process of all tabs is a key process in the manufacturing process of large cylindrical batteries. After winding, flatten the tabs, knead the vertical tabs of the cylindrical cell into a flat plane, make the tabs of each layer closely contact, and then weld the tab ends to the current collector. The thickness, tightness, and flatness of the kneading plane have a great influence on the welding effect of the collector plate and the infiltration efficiency of the electrolyte. By optimizing the kneading method, the kneading and flattening of metal shavings can be improved to a certain extent, reducing problems such as short circuits, improving the welding pass rate of the collector plate, and improving the electrolyte infiltration effect.

At present, the flattening method used for flattening the tabs of all-tab cells in the industry, after flattening, the texture of the tabs on the plane of the tabs is too messy, so the tabs fall off metal shavings during the flattening process, causing a high risk of short circuit, and Excessive feed during the kneading process will cause the kneading surface to be dense, which will affect the electrolyte infiltration rate and the coating state of the electrode edge; if the feed is too small during the kneading process, the kneading plane will be loose and not smooth enough, and the welding process of the collector plate will be easy Welding through and defective welding occur.

The existing patent publication number is CN114361555A, which discloses a method for flattening a full-tab cylindrical battery and a full-tab cylindrical battery. Rotate to the first position in the center direction; use the second kneading wheel to rotate from the center of the cell kneading plane to the outer ring direction to the second position, the path passed by the first kneading wheel does not overlap with the path passed by the second kneading wheel part. This method can effectively increase the thickness of the flat surface of the welding area of the collector plate without increasing the tab foil material, and at the same time reduce the thickness of the non-welding area, improve the welding yield of the collector plate, and improve the infiltration of the electrolyte speed, and at the same time solve the problem that the kneading plane blocks the center hole.

But the device still has the following problems:

1. During the process of kneading the second kneading flat wheel from the center of the battery cell outward, the tabs will be torn, and chips are more likely to appear, resulting in a rise in short-circuit failure;

2. There is no big difference between the lugs of the outer ring flattened by the first flattening wheel and the traditional flattened outer ring, and the thickness of the non-welding area and the improvement of wetting efficiency are limited;

3. The lug thickening area is circularly distributed on the end face of the battery core, and the welding marks are distributed on a pole piece close to the middle of the winding core. The current passing through the outer and inner pole pieces of the battery core is reduced, and the thickness distribution uniformity fluctuates greatly, and the welding effect Not easy to control.

Contents of the invention

The technical problem to be solved by the present invention is how to realize the shape optimization of the flattened lugs, improve the weld pass rate of the current collecting plate and improve the electrolyte infiltration efficiency.

The present invention solves the above-mentioned technical problems through the following technical means: a method for flattening all tabs of a cylindrical battery, comprising the following steps:

S1: through the kneading mechanism, the tabs are reciprocally rolled and pre-kneaded to make the tabs gather and pre-shape;

S2: Use the flattening mechanism to flatten and shape the gathered and pre-shaped tabs to form regularly arranged electrolyte wetted areas and collector plate welding areas.

The tabs can be gathered and pre-shaped by rolling the tabs reciprocatingly through the kneading mechanism. In the case of ensuring the flatness and thickness of the kneading plane, the arrangement of the tabs is optimized. The ears are flattened and shaped to form regularly arranged electrolyte infiltration areas and collector plate welding areas, which reduces metal scraps during the rubbing process and improves short circuit failures. Through the main functional distinctions of different areas of the tabs, the current collection Disc welding pass rate and electrolyte infiltration rate.

As a preferred technical solution, the reciprocating rolling in the step S1 includes the following steps:

S1-1: The kneading mechanism rotates clockwise from the starting position on the kneading plane of the cell to pre-shape the tabs and reaches the first position;

S1-2: The kneading mechanism rotates counterclockwise from the first position to the second position;

S1-3: The kneading mechanism rotates clockwise from the second position and returns to the first position.

Through the above three steps, the tabs can be formed flat, the tabs are regularly arranged in the electrolyte infiltration area and the current collector plate welding area with double-layer overlap of the tabs, reducing the falling of metal shavings, reducing the risk of bad short circuit of the battery cell, and having The sequential stacked wetting area can allow the electrolyte to enter at a faster speed and increase the electrolyte infiltration rate; and after the gathering area formed by the gathering and shaping is flattened, the tabs form a double-layer overlapping current collector welding area, which can obtain larger The welding process window has a significant improvement effect on the current collector plate welding penetration or poor welding.

As a preferred technical solution, in the step S2, the kneading mechanism starts to rotate from the second position to form a regularly arranged electrolyte infiltration area of the tabs and a double-layer overlapping of the tabs that can be distinguished according to the shape of the tabs. Stop after the collector plate welding area.

As a preferred technical solution, the kneading and flattening mechanism is a multi-wheel kneading and flattening roller assembly. side, and the vertical projection of the cell axis as the center of the equiangular distribution.

As a preferred technical solution, when the number of kneading and flattening rollers is four, the rotation angle in the step S1-1 is 45°, and the rotation angles in the step S1-2 and the step S1-3 are both 90°.

As a preferred technical solution, when the number of kneading flat rollers is three, the rotation angle in the step S1-1 is 60°, and the rotation angles in the step S1-2 and the step S1-3 are both 105°.

As a preferred technical solution, the kneading and flattening rollers are conical rollers, the apexes of the cones of multiple kneading and flattening rollers face the axis of the battery core, and the extension lines of the axes can intersect at one point.

As a preferred technical solution, the central axes of the multiple kneading rollers are all inclined towards the center of the battery core.

As a preferred technical solution, the gathering and pre-shaping in the step S1 is multiple times, and the final shaping effect can be improved through multiple gathering and pre-shaping.

As a preferred technical solution, the feed amount of the kneading mechanism in the step S1-1, step S1-2, and step S1-3 is the same.

The advantages of the present invention are:

(1) In the present invention, the tabs can be gathered and pre-shaped by rolling the tabs reciprocatingly through the kneading mechanism. Under the condition of ensuring the flatness and thickness of the kneading plane, the arrangement of the tabs is optimized. Knead and shape the tabs after gathering and pre-shaping to form regularly arranged electrolyte infiltration areas and current collector welding areas, which reduces metal scraps during the kneading process and improves short-circuit defects. The main functions are distinguished to improve the welding qualification rate of the collector plate and the electrolyte infiltration rate.

(2) In the present invention, through the above three steps, the tabs can be formed flat, the tabs are regularly arranged in the electrolyte infiltration area and the welding area of the current collector plate with double-layered overlap of the tabs, reducing metal filings falling and reducing battery life. The risk of poor short circuit, and the orderly stacked wetting area can allow the electrolyte to enter at a faster speed, increasing the electrolyte infiltration rate; and the gathering area formed by the gathering shape is flattened and the tabs are formed into a double-layer overlapping collector plate In the welding area, a larger welding process window can be obtained, and it has a significant improvement effect on the welding of the collector plate or the poor welding.

Description of drawings

Fig. 1 is a schematic flow chart of step S1 of a method for flattening all tabs of a cylindrical battery provided by an embodiment of the present invention;

Fig. 2 is a schematic diagram of the cell structure of a method of flattening all ears of a cylindrical battery provided by an embodiment of the present invention;

Fig. 3 is a schematic diagram of the structure of the pre-shaped tabs of a method of flattening all tabs of a cylindrical battery provided by an embodiment of the present invention;

Fig. 4 is a schematic diagram of the flattened tab structure of a method of flattening all tabs of a cylindrical battery according to an embodiment of the present invention;

Reference numerals: 1. Kneading mechanism; 2. Electric core; 3. Ears.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the present invention Examples, not all examples. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Referring to Figure 1, a method for flattening all tabs of a cylindrical battery includes the following steps:

S1: Through the kneading mechanism 1, the tabs 3 are reciprocally rolled at a fixed angle and pre-kneaded to make the tabs 3 gather and pre-shape, which can be performed multiple times according to the actual gathering and shaping effect;

S1-1: Kneading mechanism 1 rotates clockwise from the starting position on the kneading plane of battery cell 2 to pre-shape the tab 3 and reaches the first position;

S1-2: Kneading mechanism 1 rotates counterclockwise from the first position to reach the second position;

S1-3: Kneading mechanism 1 rotates clockwise from the second position and returns to the first position;

S2: Use the flattening mechanism 1 to flatten and shape the gathered and pre-shaped tabs 3 to form regularly arranged electrolyte infiltration areas and collector plate welding areas. The flattening mechanism 1 starts to rotate from the second position to After forming the regularly arranged electrolyte infiltration area of the tabs 3 that can be distinguished according to the shape of the tabs 3 and the welding area of the double-layered current collecting discs of the tabs 3, it stops, forming a double-layer overlapping current collecting plate welding area and a regular row. Electrolyte wetted area of the cloth.

Among them, the kneading and flattening mechanism 1 includes a multi-wheel kneading and flattening roller assembly. The multi-round conical kneading and flattening roller assembly includes a plurality of kneading and flattening rollers. The vertical projection of the kneading roller is an equiangular distribution of the center of the circle. The kneading roller is a conical roller. The apex of the cone of multiple kneading rollers faces the axis of the battery core 2, and the extension line of the axis can be compared with a point on the axis of the battery core 2. , wherein the kneading and flattening rollers are inclined. In this embodiment, taking four kneading and flattening rollers as an example, the rotation angle in S1-1 is 45°, and the rotation angles in step S1-2 and step S1-3 are 90° .

Refer to Figure 1 to Figure 4, the usage method is as follows:

Step 1: The kneading mechanism 1 rotates 45° clockwise from the kneading plane of the cell 2 from the starting position under a certain feed rate to pre-shape the tab 3 and reach the first position;

Step 2: Kneading mechanism 1 rotates 90° counterclockwise from the first position at the same feed rate to reach the second position;

Step 3: Kneading mechanism 1 rotates 90° clockwise from the second position and returns to the first position at the same feed rate;

Steps 2 and 3 are repeated twice to achieve the best shaping and gathering effect of the tab 3;

Step 4: The kneading and flattening mechanism 1 starts to rotate 20 times from the second position, and performs the final kneading and flattening of the tab 3;

Step 5: Carry out current collector plate welding on the above flattened battery cell 2, and adjust the position of the welding track to the flattened place after the tabs 3 are gathered; perform hipot (breakdown voltage) test on the battery cell 2 after the current collector plate welding is completed , to confirm the change of its wetting efficiency and short circuit rate;

The test results are as follows: After flattening the cell, the appearance of the ear rubbing plane confirms that the tab ear rubbing plane is flat, and the arrangement of the tabs 3 is distinct; the defect rate of hipot after rubbing is 0.07%; the welding power window of the collector plate can be increased appropriately It does not cause weld penetration, and the current collector plate weld penetration is about 0.04%.

Example 2

Referring to Fig. 2 to Fig. 4, the difference between this embodiment and embodiment 1 is that the number of kneading rollers is different. In this embodiment 2, three are taken as an example. It can be properly adjusted according to the number of rollers. The rotation angle in step S1-1 is 60°, and the rotation angle in step S1-2 and step S1-3 is 105°.

The usage method is as follows:

Step 1: Kneading mechanism 1 rotates 60° clockwise from the kneading plane of cell 2 from the starting position at a certain feed rate, pre-shape the tab 3, and reaches the first position;

Step 2: Kneading mechanism 1 rotates 105° counterclockwise from the first position at the same feed rate, and reaches the second position;

Step 3: Kneading mechanism 1 rotates 105° clockwise from the second position and returns to the first position at the same feed rate;

Steps 2 and 3 are repeated twice to achieve the best shaping and gathering effect of the tab 3;

Step 4: The kneading and flattening mechanism 1 starts to rotate 20 times from the second position, and performs the final kneading and flattening of the tab 3;

Step 5: Carry out current collector plate welding on the above flattened battery cell 2, and adjust the position of the welding track to the flattened place after the tabs 3 are gathered; perform hipot (breakdown voltage) test on the battery cell 2 after the current collector plate welding is completed, Confirm the change of wetting efficiency and short circuit rate.

The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be described in the foregoing embodiments Modifications are made to the recorded technical solutions, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. The full lug rubbing and flattening method for the cylindrical battery is characterized by comprising the following steps of:

s1: the pole lugs are rolled in a reciprocating way through a rubbing mechanism and are pre-rubbed and flattened, so that the pole lugs are gathered and pre-shaped;

s2: and rubbing and shaping the pole lugs after gathering and pre-shaping through a rubbing and shaping mechanism, and forming regularly arranged electrolyte infiltration areas and current collecting disc welding areas.

2. The method for rolling and flattening all tabs of a cylindrical battery according to claim 1, wherein the reciprocating rolling in the step S1 comprises the steps of:

s1-1: the kneading mechanism rotates clockwise from the initial position to pre-shape the tab in the electric core kneading plane and reaches the first position;

s1-2: the rubbing mechanism rotates anticlockwise from the first position to the second position;

s1-3: the rubbing mechanism rotates clockwise from the second position and returns to the first position.

3. The method for rolling and flattening all tabs of a cylindrical battery according to claim 2, wherein in the step S2, the rolling and flattening mechanism starts rotating from the second position to form electrolyte soaking areas regularly arranged according to tab morphology and a double-layer overlapping current collecting disc welding area of the tabs, and then stops.

4. The method for rolling all tabs of a cylindrical battery according to claim 1, wherein the rolling mechanism is a multi-wheel rolling roller assembly, the multi-wheel conical rolling roller assembly comprises a plurality of rolling rollers, and the rolling rollers are arranged on the pre-rolling side of the battery core and are distributed at equal angles with the vertical projection of the axis of the battery core as the center of a circle.

5. The method for rolling and flattening all tabs of a cylindrical battery according to claim 4, wherein when the number of the rolling and flattening rollers is four, the rotation angle in the step S1-1 is 45 °, and the rotation angles in the step S1-2 and the step S1-3 are 90 °.

6. The method for rolling and flattening all tabs of a cylindrical battery according to claim 4, wherein when the number of rolling and flattening rollers is three, the rotation angle in the step S1-1 is 60 °, and the rotation angles in the step S1-2 and the step S1-3 are 105 °.

7. The method of claim 4, wherein the rolling roller is a conical roller, conical peaks of the rolling rollers face the axis of the battery shaft, and extension lines of the axes of the rolling rollers are intersected with each other.

8. The method for rolling all tabs of a cylindrical battery according to claim 7, wherein the central axes of the rolling rollers are inclined toward the center of the battery cell.

9. The method for rolling and flattening all tabs of a cylindrical battery according to claim 1, wherein the step S1 is performed a plurality of times.

10. The method for rolling and flattening all tabs of a cylindrical battery according to claim 2, wherein the feeding amounts of the rolling and flattening mechanisms in the steps S1-1, S1-2 and S1-3 are the same.

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