Novel device for enhancing strength of tab

Abstract

The utility model relates to the technical field of lithium ion batteries, and discloses a novel device for enhancing the strength of a tab, which comprises two rolling gears, tooth top surfaces, tooth groove surfaces and tooth side surfaces between the tooth groove surfaces and the tooth top surfaces of the rolling gears are planes, the width of the tooth top surfaces is a ', the width of the tooth side surfaces is b', the width of the tooth groove surfaces is c ', and the width of the tooth top surfaces is a'. A '= b' = c ', the included angle formed between the tooth top surface and the tooth side surface is alpha', the included angle formed between the tooth side surface and the tooth groove bottom surface is beta ', the number of teeth is n, and beta' = alpha '-180 degrees / n. The utility model has the following advantages and effects: the two rolling gears can pressurize copper or aluminum foil to form a reinforcing mark to enhance the strength, so that the foil is prevented from being folded or wrinkled after being cut into a tab by a hardware die-cutting tool or laser, and the tab can be effectively prevented from being turned over and pseudo soldering during welding.

Description

TECHNICAL FIELD

[0001] The utility model relates to lithium ion battery technical field, especially increase new device of strength of tab. BACKGROUND

[0002] The tab of lithium ion battery plays the role of leading out the positive and negative electrode from the battery cell as a conductor. The positive electrode often uses aluminum tab, and the negative electrode uses copper tab. The most commonly used ones at present are mainly multi-tab winding and single-tab lamination. The multi-tab winding is to insert the separator, negative electrode and positive electrode into the winding needle in turn through the fixed winding needle for winding. Because the winding process is often single-tab output current, and the lamination cell is multiple tabs in parallel welding, the lithium ion migration path is greatly reduced during the charging and discharging process, so the winding battery often has higher internal resistance. The lamination process is to stack the negative electrode, separator and positive electrode like a sandwich on the lamination table to form a cell. Because each piece of the lamination process needs to be welded to a welding point, it is more difficult to weld and more prone to false welding. No matter which process has certain requirements for the strength of the tab, otherwise the tab may be turned over or false welding and other abnormalities may occur. SUMMARY

[0003] The utility model discloses a new device for enhancing the strength of the tab, which has the effects of pressing the foil area of the positive and negative electrodes, preventing the foil from being folded or wrinkled after being cut into tabs by hardware die cutter or laser cutting, and enhancing the strength of the tab by forming a reinforcing mark.

[0004] The above technical purpose of the utility model is realized by the following technical scheme: a new device for enhancing the strength of the tab, comprising two roller gears, the tooth top surface, tooth groove surface, and tooth side surface between the tooth groove surface and the tooth top surface of the roller gear are all planes, the width of the tooth top surface is a', the width of the tooth side surface is b', the width of the tooth groove surface is c', a'=b'=c', the included angle between the tooth top surface and the tooth side surface is alpha', the included angle between the tooth side surface and the tooth groove bottom surface is beta', the number of teeth is n, and beta'=alpha'-180° / n.

[0005] The utility model further provides that: the gear edge is provided with a round corner, the radius of the round corner is r, the thickness of the foil processed by the roller gear is t, and r / t is less than 4.

[0006] The utility model further provides that: r / t=2.

[0007] The utility model further provides that: r=0.1mm, and t=0.05mm.

[0008] The utility model further provides that: the maximum gap value of the two gears of the roller gear, and the maximum gap value is the minimum value when the roller gear does not interfere during the roller forming process.

[0009] The present invention is further configured as follows: the maximum gap value is 0.2 mm.

[0010] The present invention is further configured as follows: α′=120°.

[0011] The present invention is further configured as follows: n is divisible by 360, n=24.

[0012] The present invention is further configured as follows: the radius of the rolling gear is R, R=L / 2sin(θ / 2), L is the chord length of the profiles on both sides of a tooth unit, and θ is the central angle corresponding to a tooth unit.

[0013] The present invention is further configured as follows: a′=b′=c′=2.61 mm, R=30 mm.

[0014] The beneficial effects of the utility model are:

[0015] 1. Place the foil between two rolling gears and complete the formation of the reinforcement mark by rolling. The rolling gears have a′=b′=c′, α′=120°, so that the foil is formed into a corrugated board. The formed corrugated board is a semi-regular hexagon.

[0016] 2. Under the same other conditions, the smaller the r / t, the smaller the springback of the corrugated board after roll forming. When r / t is less than 4, the elastic deformation zone is very small. To reduce the springback value, r / t should be as small as possible.

[0017] 3. An important parameter for roll-formed gears is the maximum clearance between the two gears. A too small maximum clearance can result in excessive forming force, causing the foil to break; a too large maximum clearance can result in insufficient forming force, resulting in incomplete foil forming and reduced dimensional accuracy. Taking into account other parameters of the forming gears, a maximum clearance of 0.2mm can avoid situations where the maximum clearance is too large or too small.

[0018] 4. During the roll forming process, gears that are too deep and too thin can easily press through the foil, while gears that are too small and too narrow can easily fail to achieve the desired effect of improving the tab strength. For a foil with a thickness of 0.05mm, a′=b′=c′=2.61mm, R=30mm, α′=120°, r=0.1mm, and n=24, the foil can be roll formed well without pressing through the foil, while achieving the desired effect of improving the tab strength.

[0019] 5. The two rolling gears of the utility model can pressurize the copper or aluminum foil to form a reinforcing mark to enhance the strength, prevent the foil from folding or wrinkling after being cut into tabs by hardware die-cutting tools or laser cutting, and effectively avoid the tabs from flipping over and the occurrence of cold welding during welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 It is a structural diagram of the present utility model.

[0022] Figure 2 It is a schematic diagram of the structure of the formed corrugated board of the utility model.

[0023] Figure 3 This is a schematic diagram of the tooth unit structure of the roller gear of the utility model

[0024] In the figure, 1, rolling gear; 2, foil; 3, corrugated board; a and b are the side lengths of the semi-regular hexagon of the corrugated board; α is the angle formed between two adjacent sides of the semi-regular hexagon of the corrugated board; a′, the width of the tooth top surface; b′, the width of the tooth side surface; c′, the width of the tooth groove surface; α′, the angle formed between the tooth top surface and the tooth side surface; β′, the angle formed between the tooth side surface and the tooth groove bottom surface; r, the fillet radius; t, the thickness of the foil; R, the radius of the rolling gear; n, the number of teeth. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions of the present invention in conjunction with specific embodiments. Obviously, the embodiments described are only some of the embodiments of the present invention, and not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0026] A device for enhancing the strength of a tab includes two rolled gears 1. The tooth top surface, tooth groove surface, and tooth side surface between the tooth groove surface and the tooth top surface of the rolled gear 1 are all planes. The width of the tooth top surface is a′, the width of the tooth side surface is b′, and the width of the tooth groove surface is c′, where a′=b′=c′=2.61 mm. The angle formed between the tooth top surface and the tooth side surface is α′, where α′=120°. The angle formed between the tooth side surface and the tooth groove bottom surface is β′, the number of teeth is n, where n=24, and β′=α′-180° / n. The gear edges of the rolled gear 1 are rounded, with a fillet radius of r, where r=0.1 mm. The thickness of the foil is t, where t=0.05 mm. r / t=2.

[0027] The maximum gap value of the two gears of the roll forming gear 1 is the minimum value when the roll forming gear 1 does not interfere in the roll forming process, and the maximum gap value is 0.2 mm. The radius of the roll forming gear 1 is R, R = L / 2sin(θ / 2), L is the chord length of the profile on both sides of a tooth unit, θ is the central angle corresponding to a tooth unit, and R = 30 mm is calculated.

[0028] The foil 2 of copper or aluminum is placed between the two roll forming gears 1, and the foil 2 is formed into a corrugated board 3 by roll forming. The corrugated board 3 is a semi-regular hexagon, and the side length of the semi-hexagon is a = b = 2.61 mm. The included angle α between two adjacent side lengths is 120°.

Claims

1. A new device for enhancing the strength of the tab, characterized by: The invention comprises two rolling gears (1), wherein the tooth top surface, tooth groove surface, and tooth side surface between the tooth groove surface and the tooth top surface of the rolling gear (1) are all planes, the width of the tooth top surface is a′, the width of the tooth side surface is b′, the width of the tooth groove surface is c′, a′=b′=c′, the angle formed between the tooth top surface and the tooth side surface is α′, the angle formed between the tooth side surface and the tooth groove bottom surface is β′, the number of teeth is n, and β′=α′-180° / n.

2. The novel device for enhancing tab strength according to claim 1, characterized in that: The gear edge is provided with a fillet, the fillet radius is r, the foil material (2) processed by the rolled gear (1) has a thickness of t, and r / t is less than 4.

3. The novel device for enhancing tab strength according to claim 2, characterized in that: r / t＝2。 4. The novel device for enhancing tab strength according to claim 3 is characterized in that: r=0.1mm, t=0.05mm.

5. The novel device for enhancing tab strength according to any one of claims 1 to 4, characterized in that: The maximum gap value between the two gears of the rolling gear (1) is the minimum value when the rolling gear (1) does not interfere with each other during the rolling forming process.

6. The novel device for enhancing tab strength according to claim 5, characterized in that: The maximum gap value is 0.2mm.

7. The novel device for enhancing tab strength according to any one of claims 1 to 4, characterized in that: α′＝120°。 8. The novel device for enhancing tab strength according to any one of claims 1 to 4, characterized in that: n is divisible by 360, n=24.

9. The novel device for enhancing tab strength according to claim 4 or 6, characterized in that: The radius of the roller gear (1) is R, R=L / 2sin(θ / 2), L is the chord length of the profile on both sides of a tooth unit, and θ is the central angle corresponding to a tooth unit.

10. The novel device for enhancing tab strength according to any one of claim 9, characterized in that: a′=b′=c′=2.61mm, R=30mm.

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