High-power small cylindrical lithium ion battery

Abstract

The utility model discloses a high-power small cylindrical lithium ion battery. The high-power small cylindrical lithium ion battery comprises a positive plate, a negative plate and a diaphragm, the positive plate and the negative plate are isolated by the diaphragm to achieve an insulation effect; the positive plate comprises a positive current collector and a positive active material arranged on the surface of the positive current collector; the positive plate also comprises two positive tab structures, a positive plate head structure and a positive plate tail structure; and the two tab structures of the positive plate are arranged between 1 / 4 and 3 / 4 of the length direction of the positive plate. The positive plate head structure and the positive plate tail structure are arranged, so that the problem that the diaphragm is punctured due to expansion of the roll core after charging and discharging can be solved, and the risks of short circuit and self-discharging are reduced; the two tab structures of the positive plates and the design of different blank gap widths ensure that in the battery production process, by adjusting the positions of the tabs welded on the blank current collector, the difficulty degree of alignment of the tabs of the two positive plates is reduced, and the percent of pass is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to lithium ion battery technical field, concretely relates to a high power type small cylindrical lithium ion battery. BACKGROUND

[0002] Small cylindrical lithium ion battery, commonly seen in 18650, 21700 etc. model, production automation degree is high, and module scheme is simple. In the field of portable electronic equipment, electric tool and electric two -wheeled vehicle etc., more and more get widespread application, and at the same time also put forward higher requirements to its energy density and rate performance.

[0003] The internal cylindrical winding core of small cylindrical lithium ion battery is winding process, and the pole lug is welded on the positive and negative pole to output electric energy, theoretically, the more the pole lug, the better the rate performance of the internal conductive performance of the cell and the internal resistance reduction. Common small cylindrical battery generally designs one or two pole lugs on the positive and negative pole, greatly limits the output power of small cylindrical lithium battery. However, increasing the number of pole lugs will not only occupy the space of positive and negative active material inside the cell, cause the reduction of battery energy density, but also cause the difficulty of pole lug alignment, reduce the production qualified rate and production efficiency.

[0004] In order to solve the above problems, the utility model is proposed. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a high power type small cylindrical lithium ion battery, which aims at guaranteeing the energy density of the battery, improving the production qualified rate and production efficiency and realizing the high power demand.

[0006] In order to solve the above technical problems, the following technical scheme is adopted:

[0007] A high power type small cylindrical lithium ion battery, comprising a positive plate, a negative plate and a separator, wherein the positive plate and the negative plate are separated by the separator to achieve insulation effect.

[0008] The positive plate comprises a positive current collector, a positive active material arranged on the surface of the positive current collector, two positive lug structures, a positive plate head structure and a positive plate tail structure, and the two positive lug structures of the positive plate are arranged between 1 / 4 and 3 / 4 of the length direction of the positive plate.

[0009] The first positive lug structure is composed of a blank current collector, a lug welded on the blank current collector and a polyimide high-temperature adhesive paper covering the blank current collector and the lug, wherein the blank current collector is 10-15mm long, the lug is a soft aluminum strip with a thickness of 0.06-0.1mm and a width of 3-5mm, and the polyimide high-temperature adhesive paper is 13-18mm long and completely covers the blank current collector and the lug.

[0010] The second positive pole lug structure is composed of a blank current collector, a pole lug welded on the blank current collector, and a polyimide high-temperature adhesive paper covering the blank current collector and the pole lug; the blank current collector is 8-10mm long, the pole lug is a soft aluminum strip with a thickness of 0.06-0.1mm and a width of 3-5mm, and the polyimide high-temperature adhesive paper is 11-13mm long and completely covers the blank current collector and the pole lug.

[0011] The positive pole piece head structure and the positive pole piece tail structure are the same, the positive pole piece head structure is a right end head, and the positive pole piece tail structure is a left end head, both of which are composed of a blank current collector and a polyimide high-temperature adhesive paper covering the blank current collector; the blank current collector is 4-8mm long, and the polyimide high-temperature adhesive paper is 6-10mm long and completely covers the blank current collector.

[0012] The negative pole piece comprises a negative pole current collector, a negative pole active material layer arranged on the surface of the negative pole current collector, and a negative pole current collector exposed area; the negative pole current collector exposed area is located below the negative pole active material layer and is used for outputting electric energy; and the negative pole current collector of the negative pole current collector exposed area is double-exposed, with a width of 5-15mm.

[0013] The separator completely covers the negative pole active material layer of the negative pole piece, and the negative pole active material layer of the negative pole piece completely covers the positive pole piece, and the cylindrical battery roll core is made in a winding manner; the positive pole lug is exposed above the cylindrical battery roll core, and the negative pole current collector exposed area is exposed below the cylindrical battery roll core and is used for outputting electric energy; the separator is a high-porosity PE separator, and the PE separator is single-sided or double-sided coated with a ceramic layer with a thickness of 2-4um.

[0014] Beneficial technical effects:

[0015] 1. The utility model sets up the positive pole piece head structure and the positive pole piece tail structure, can solve the problem that the roll core expands after charging and discharging, causes the separator to be punctured, reduces the risk of short circuit and self-discharge.

[0016] 2. The two pole lug structures of the positive pole piece have different blank gap width designs, which ensure that, in the battery production process, the difficulty of aligning the two pole lugs of the positive pole piece is reduced and the qualified rate is improved by adjusting the welding position of the pole lug on the blank current collector.

[0017] 3. The negative pole piece structure takes the negative pole current collector exposed area as a pole lug, greatly shortens the transmission path of electrons, reduces the internal resistance and temperature rise of the battery, and thus improves the safety performance and rate performance of the small cylindrical lithium ion battery; at the same time, the small cylindrical lithium ion battery does not increase the number of traditional pole lugs compared with a conventional battery, and the "pole lug-free" design of the negative pole piece reduces the processing difficulty and improves the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0018] The utility model discloses further illustrate below the drawing.

[0019] Figure 1 It is the structure schematic drawing of cylindrical battery roll core of winding of embodiment 1 in the utility model.

[0020] Figure 2 It is the polar piece arrangement drawing of embodiment 1 in the utility model after columnar roll core unfolding.

[0021] Figure 3 It is the structure schematic drawing of cylindrical battery roll core of winding of embodiment 1 in the utility model.

[0022] Figure 4 It is the structure schematic drawing of positive pole piece of embodiment 1 in the utility model.

[0023] Figure 5 It is the structure schematic drawing of positive pole piece of embodiment 1 in the utility model.

[0024] Figure 6 It is the structure schematic drawing of negative pole piece of embodiment 1 in the utility model.

[0025] Figure 7 It is the structure schematic drawing of negative pole piece of embodiment 1 in the utility model.

[0026] In the drawing, 1, positive pole piece;11, positive pole current collector;12, positive pole active material layer;13, polyimide high temperature glue paper;14, head blank part;15, first gap part;16, second gap part;17, tail blank part;18, first positive pole lug;19, second positive pole lug;2, negative pole piece;21, negative pole current collector;22, negative pole active material layer;23, negative pole current collector exposed area;3, diaphragm;4, battery columnar roll core;5, expansion glue paper. DETAILED DESCRIPTION

[0027] The technical scheme in the utility model embodiment will be described clearly and completely below in conjunction with the utility model embodiments, and obviously, the described embodiments only are a part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without making creative labor all belong to the scope of protection of the utility model.

[0028] Embodiment 1

[0029] Refer to Figures 1-7As shown, a high-power small cylindrical lithium ion battery includes a positive electrode sheet 1, a negative electrode sheet 2 and a separator 3; the positive electrode sheet 1 includes a positive electrode current collector 11, a positive electrode active material layer 12 coated on both sides of the positive electrode current collector 11, a first positive electrode tab 18 and a second positive electrode tab 19; the right end of the positive electrode current collector 11, the length direction between 1 / 4 and 3 / 4 from the right, and the left end are respectively provided with a head blank part 14 without coating the positive electrode active material layer on both sides, a first gap part 15, a second gap part 16 and a tail blank part 17; the first positive electrode tab 18 is arranged in the first gap part 15 of the positive side of the positive electrode current collector 11 and is fixedly connected with the positive electrode current collector 11 by ultrasonic welding, and the upper end of the first positive electrode tab 18 exceeds the positive electrode current collector 11; the second positive electrode tab 19 is arranged in the second gap part 16 of the positive side of the positive electrode current collector 11 and is fixedly connected with the positive electrode current collector 11 by ultrasonic welding, and the upper end of the second positive electrode tab 19 exceeds the positive electrode current collector 11.

[0030] The head blank part 14, the first gap part 15, the second gap part 16 and the tail blank part 17 are respectively provided with a polyimide high-temperature adhesive paper 13 on the outer side of both sides, and the polyimide high-temperature adhesive paper 13 completely covers the corresponding head blank part 14, the first gap part 15, the second gap part 16 and the tail blank part 17.

[0031] The negative electrode sheet 2 includes a negative electrode current collector 21, a negative electrode active material layer 22 coated on both sides of the negative electrode current collector 21, and a negative electrode current collector exposed area 23 without coating the negative electrode active material.

[0032] The positive electrode sheet 1, the separator 3, the negative electrode sheet 2 and the separator 3 are stacked together from top to bottom, the negative electrode active material layer 22 completely covers the positive electrode sheet 1, the separator 3 completely covers the negative electrode active material layer 22 of the negative electrode and the positive electrode sheet 1, and the first positive electrode tab 18 and the second positive electrode tab 19 are arranged in the same position from the upper end of the cylindrical battery roll core 4, and the negative electrode current collector exposed area 23 is arranged from the lower end of the cylindrical battery roll core 4, and finally the cylindrical battery roll core 4 is fixed by using the expansion adhesive paper 5 outside.

[0033] As a preferred, the length of the head blank part 14 and the tail blank part 17 of the positive electrode sheet 1 is set to 6mm, and the length of the polyimide high-temperature adhesive paper 13 corresponding to the head blank part 14 and the tail blank part 17 is set to 7mm, which completely covers the head blank part 14 and the tail blank part 17.

[0034] As a preferred, the length of the first gap part 15 of the positive electrode sheet 1 is set to 15mm, and the length of the polyimide high-temperature adhesive paper 13 corresponding to the first gap part 15 is set to 18mm, which completely covers the first gap part 15.

[0035] As preferred, the first positive electrode tab 18 is set to have a thickness of 0.1 mm and a width of 4 mm.

[0036] As preferred, the length of the second gap part 16 of the positive electrode sheet 1 is set to 10 mm, and the length of the polyimide high-temperature adhesive paper 13 corresponding to the second gap part 16 is set to 13 mm, so as to completely cover the second gap part 16.

[0037] As preferred, the second positive electrode tab 19 is set to have a thickness of 0.08 mm and a width of 3.5 mm.

[0038] As preferred, the width of the negative electrode current collector exposed area 23 of the negative electrode sheet 2 is set to 10 mm.

[0039] As preferred, the separator 3 is a high-porosity PE separator, and a 4-um ceramic layer is coated on the PE separator.

[0040] The utility model discloses a blank current collector is arranged at the head and tail of the positive electrode sheet 1, and the outer side of the blank current collector is pasted with the polyimide high-temperature adhesive paper 13, effectively solve the problem that the separator 3 is punctured by the positive active material layer 12 of the two ends of the positive electrode sheet 1 in the prior art and causes short circuit, reduce the risk of battery short circuit and self-discharge, set the negative electrode current collector exposed area 23 of the negative electrode sheet, replace the traditional tab, greatly shorten the transmission path of electron, reduce the internal resistance and temperature rise of battery, realize the demand of high power.

[0041] In addition, it should be understood that, although the present specification is described according to the embodiments, not every embodiment contains only one independent technical scheme, the description mode of the specification is only for the sake of clarity, and the person skilled in the art should take the specification as a whole, and the technical scheme in each embodiment can also be combined appropriately to form other embodiments that can be understood by the person skilled in the art.

Claims

1. A high-power type small cylindrical lithium ion battery comprising a positive electrode sheet, a negative electrode sheet, and a separator; characterized by, The positive electrode sheet comprises a positive electrode current collector, a positive electrode active material arranged on the surface of the positive electrode current collector; the positive electrode sheet further comprises two positive electrode tab structures, a positive electrode sheet head structure and a positive electrode sheet tail structure; the two positive electrode tab structures of the positive electrode sheet are arranged between 1 / 4 and 3 / 4 of the length direction of the positive electrode sheet.

2. The high-power small cylindrical lithium-ion battery according to claim 1, wherein, The first positive electrode tab structure is composed of a blank current collector, a tab welded on the blank current collector, and a polyimide high-temperature adhesive paper covering the blank current collector and the tab.

3. The high-power small cylindrical lithium-ion battery according to claim 2, wherein, The blank current collector is 10-15 mm long, the tab is a soft aluminum strip with a thickness of 0.06-0.1 mm and a width of 3-5 mm, and the polyimide high-temperature adhesive paper is 13-18 mm long.

4. The high-power small cylindrical lithium-ion battery according to claim 1, wherein, The second positive electrode tab structure is composed of a blank current collector, a tab welded on the blank current collector, and a polyimide high-temperature adhesive paper covering the blank current collector and the tab.

5. The high-power small cylindrical lithium-ion battery according to claim 4, characterized in that, The blank current collector is 8-10 mm long, the tab is a soft aluminum strip with a thickness of 0.06-0.1 mm and a width of 3-5 mm, and the polyimide high-temperature adhesive paper is 11-13 mm long.

6. The high-power small cylindrical lithium-ion battery according to claim 1, wherein, The positive electrode sheet head structure and the positive electrode sheet tail structure are the same, the positive electrode sheet head structure is a right end head, and the positive electrode sheet tail structure is a left end head, both of which are composed of a blank current collector and a polyimide high-temperature adhesive paper covering the blank current collector, wherein the blank current collector is 4-8 mm long, and the polyimide high-temperature adhesive paper is 6-10 mm long.

7. The high-power small cylindrical lithium-ion battery according to claim 2, characterized in that, The negative electrode sheet comprises a negative electrode current collector, a negative electrode active material layer arranged on the surface of the negative electrode current collector, and a negative electrode current collector exposed area, wherein the negative electrode current collector exposed area is located below the negative electrode active material layer and is used for outputting electric energy, and the negative electrode current collector of the negative electrode current collector exposed area is double-exposed.

8. The high-power small cylindrical lithium-ion battery according to claim 7, wherein, The separator completely covers the negative electrode active material layer of the negative electrode sheet, and the negative electrode active material layer of the negative electrode sheet completely covers the positive electrode sheet, and a cylindrical battery roll core is made by winding.

9. The high-power small cylindrical lithium-ion battery according to claim 8, wherein, The positive electrode tab is exposed above the cylindrical battery roll core, and the negative electrode current collector exposed area is exposed below the cylindrical battery roll core and is used for outputting electric energy.

10. The high-power small cylindrical lithium-ion battery according to claim 1, wherein, The separator is a high-porosity PE separator, and the PE separator is coated with a ceramic layer with a thickness of 2-4 um on one side or both sides.

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