Polymer lithium battery capable of improving energy density

Abstract

The utility model discloses a polymer lithium battery capable of improving energy density, which comprises a positive plate, a negative plate, a diaphragm, a positive lug, a negative lug and ending glue, the positive plate, the negative plate and the diaphragm are combined into a battery cell of the polymer lithium battery by adopting a winding structure, the diaphragm is arranged between the positive plate and the negative plate, the positive lug is arranged on the positive plate, and the negative lug is arranged on the negative plate. The negative tab is arranged on the negative plate, the ending glue, the positive tab and the negative tab are arranged in a staggered manner in the width direction of the battery cell, the positive plate is provided with a slot position through laser cleaning, and the positive tab is arranged in the slot position. According to the mode, the ending glue, the positive electrode lug and the negative electrode lug are arranged in the width direction of the battery cell in a staggered manner, so that the ending glue is prevented from being overlapped with the thickness of the positive electrode lug and the thickness of the negative electrode lug in the thickness direction of the battery cell, the thickness of the battery cell is reduced, and the energy density of the polymer lithium battery is effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of polymer lithium batteries, and particularly relates to a polymer lithium battery capable of improving energy density. Background Art

[0002] The polymer lithium battery, namely the lithium-ion battery, has become the first choice for various portable electronic products due to its high energy density, wide operating temperature range, stable charge retention ability, long cycle life, and good environmental friendliness. However, the current design of polymer lithium batteries is becoming more and more extreme, and the foil and diaphragm are getting thinner and thinner. How to improve the energy density has become a challenge for polymer lithium batteries.

[0003] Among them, the polymer lithium battery usually includes a positive electrode sheet, a negative electrode sheet, a separator, a positive electrode tab, a negative electrode tab, and a finishing glue, etc. The positive electrode sheet, the negative electrode sheet, and the separator are combined into the battery core of the polymer lithium battery by a winding structure, and the finishing glue is used to be attached to the battery core after the winding work is completed. However, as Figure 3 shown, in the polymer lithium battery of the prior art, the finishing glue is located in the middle position of the battery core, and the finishing glue overlaps with the positive electrode tab and the negative electrode tab in the width direction of the battery core. The finishing glue will cause the thickness superposition with the positive electrode tab or the negative electrode tab in the thickness direction of the battery core, that is, the overall thickness of the battery core increases, thereby affecting the energy density of the polymer lithium battery. Summary of the Utility Model

[0004] (I) Technical Problems to be Solved

[0005] In view of the deficiencies of the prior art, the utility model provides a polymer lithium battery capable of improving energy density, which can solve the above technical problems.

[0006] (II) Technical Solutions

[0007] To solve the above technical problems, the utility model provides the following technical solutions: A polymer lithium battery capable of improving energy density includes a positive electrode sheet, a negative electrode sheet, a separator, a positive electrode tab, a negative electrode tab, and a finishing glue. The positive electrode sheet, the negative electrode sheet, and the separator are combined into the battery core of the polymer lithium battery by a winding structure. The separator is arranged between the positive electrode sheet and the negative electrode sheet. The positive electrode tab is arranged on the positive electrode sheet, and the negative electrode tab is arranged on the negative electrode sheet. The finishing glue is arranged staggeredly with the positive electrode tab and the negative electrode tab in the width direction of the battery core. The positive electrode sheet is provided with a slot, and the positive electrode tab is arranged in the slot.

[0008] Preferably, the slot is located in the double-sided fabric area at the head of the positive electrode sheet.

[0009] Preferably, the double-sided fabric area at the head of the positive electrode sheet is formed by laser cleaning to form the slot.

[0010] Preferably, one side of the head of the negative electrode sheet is coated with a negative electrode active material and the other side is not coated with a negative electrode active material.

[0011] Preferably, the negative electrode tab is arranged on the other side of the head of the negative electrode sheet.

[0012] Preferably, the end sealant is located on the right side of the battery cell.

[0013] (III) Beneficial effects

[0014] Compared with the prior art, the present utility model provides a polymer lithium battery capable of improving the energy density, having the following beneficial effects: the end sealant of the present utility model is arranged staggeredly with the positive electrode tab and the negative electrode tab in the width direction of the battery cell, so as to avoid the thickness superposition of the end sealant and the positive electrode tab and the negative electrode tab in the thickness direction of the battery cell, reduce the thickness of the battery cell, and thus improve the energy density of the polymer lithium battery. Description of the drawings

[0015] Figure 1 It is the first structural schematic diagram of a polymer lithium battery capable of improving the energy density according to the present utility model;

[0016] Figure 2 It is the second structural schematic diagram of a polymer lithium battery capable of improving the energy density according to the present utility model;

[0017] Figure 3 It is the structural schematic diagram of a polymer lithium battery of the prior art;

[0018] Figure 4 It is the first structural schematic diagram of the positive electrode sheet and the negative electrode sheet according to the present utility model;

[0019] Figure 5 It is the second structural schematic diagram of the positive electrode sheet and the negative electrode sheet according to the present utility model;

[0020] Figure 6 It is the first structural schematic diagram of the positive electrode sheet and the negative electrode sheet of the prior art;

[0021] Figure 7 It is the second structural schematic diagram of the positive electrode sheet and the negative electrode sheet of the prior art.

[0022] The reference numerals in the figures are: 1 positive electrode sheet, 2 negative electrode sheet, 3 separator, 4 positive electrode tab, 5 negative electrode tab, 6 end sealant, 7 battery cell, 8 adhesive tape, 11 positive electrode current collector, 12 positive electrode active material, 13 slot, 21 negative electrode current collector, 22 negative electrode active material. Detailed implementation manners

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0024] The present utility model provides a polymer lithium battery capable of improving energy density, which includes a positive electrode sheet 1, a negative electrode sheet 2, a separator 3, a positive electrode tab 4, a negative electrode tab 5, and a finishing glue 6. The positive electrode sheet 1, the negative electrode sheet 2, and the separator 3 are combined into a battery core 7 of the polymer lithium battery by a winding structure. The separator 3 is arranged between the positive electrode sheet 1 and the negative electrode sheet 2. The positive electrode tab 4 is arranged on the positive electrode sheet 1, and the negative electrode tab 5 is arranged on the negative electrode sheet 2. The finishing glue 6 is arranged staggered with the positive electrode tab 4 and the negative electrode tab 5 in the width direction of the battery core 7. The positive electrode sheet 1 is provided with a slot 13, and the positive electrode tab 4 is arranged in the slot 13 to better protect the positive electrode tab 4.

[0025] The finishing glue 6 is used to be pasted on the battery core 7 after the winding work of the polymer lithium battery is completed. The finishing glue 6 can adopt the PET adhesive tape of the existing technology. It can be understood that the finishing glue 6 of the present utility model is arranged staggered with the positive electrode tab 4 and the negative electrode tab 5 in the width direction of the battery core 7 to avoid the thickness superposition of the finishing glue 6 and the positive electrode tab 4 and the negative electrode tab 5 in the thickness direction of the battery core 7, so as to reduce the thickness of the battery core (battery), that is, reduce the volume of the battery core 7. Further, the energy density of the battery is the ratio of the energy of the battery to the volume of the battery. Therefore, the present utility model improves the energy density of the polymer lithium battery by reducing the volume of the polymer lithium battery. Specifically, the finishing glue 6 can be located on the right side of the battery core 7; the battery core 7 is square.

[0026] In addition, the positive electrode sheet 1 includes a positive electrode current collector 11 (such as aluminum foil) and a positive electrode active material 12 coated on the surface of the positive electrode current collector 11, and the negative electrode sheet 2 includes a negative electrode current collector 21 (such as copper foil) and a negative electrode active material 22 coated on the surface of the negative electrode current collector 21. Adhesive tapes 8 can be arranged on the positive electrode sheet 1 and the negative electrode sheet 2.

[0027] As Figure 4-5 shown, in this embodiment, the above slot 13 is specifically located in the double-sided coating area at the head of the positive electrode sheet 1. It can be understood that the double-sided coating area at the head of the positive electrode sheet 1 means that both surfaces of the head of the positive electrode sheet 1 are coated with the positive electrode active material 12; in addition, one surface of the head of the negative electrode sheet 2 is coated with the negative electrode active material 22 and the other surface is not coated with the negative electrode active material 22, that is, the head of the negative electrode sheet 2 is a single-sided coating area, and the negative electrode tab 5 is arranged on the above-mentioned other surface of the head of the negative electrode sheet 2. In addition, as Figure 6-7As shown, in the prior art, neither of the two surfaces of the head of the positive electrode sheet 1 is coated with the positive electrode active material 12, and neither of the two surfaces of the head of the negative electrode sheet 2 is coated with the negative electrode active material 22. The positive electrode tab 4 is arranged on the head of the positive electrode sheet 1, and the negative electrode tab 5 is arranged on the head of the negative electrode sheet 2. Compared with the prior art, the heads of the positive electrode sheet 1 and the negative electrode sheet 2 of this embodiment are both coated with active materials, which can increase the active material area of the polymer lithium battery, that is, increase the battery energy (capacity), so as to further improve the energy density of the polymer lithium battery.

[0028] Preferably, the double-sided material area at the head of the positive electrode sheet 1 is formed with a slot 13 by laser cleaning. Laser cleaning is to remove the active material coated on the surface of the current collector by laser cleaning, and the dust is processed by a dust removal system to generate the slot: in the double-sided material area at the head of the positive electrode sheet 1, the positive electrode active material 12 coated on the surface of the positive electrode current collector 11 is removed by laser cleaning, and the dust is processed by a dust removal system to generate the above slot 13. Laser cleaning can reduce the loss of active materials. Further, the positive electrode tab 4 is preferably arranged in the slot 13 by welding.

[0029] Taking the polymer lithium battery with a thickness of 5.1 mm, a width of 61 mm, a height of 81 mm, and a capacity of 4220 mAh, the battery 516181PPN4420 as an example, the head of the battery core winding adopts an "interlocking" winding structure. By laser cleaning, a double-sided material of one fold can be added, and one layer of copper foil and aluminum foil can be reduced: (1) Calculated according to the 516181PPN4420 battery with a width of 61 mm, after deducting the laser cleaning ear slot (slot) of 10 mm, the single-sided material length can be increased by 102 mm, and the effective active material area can be increased by 5.5%; (2) The aluminum foil of the 516181PPN4420 battery uses 12 μm, and the copper foil uses 8 μm. By reducing one layer of aluminum foil, the battery thickness can be reduced by 0.012 mm, that is, the thickness can be reduced by 0.24%; (3) Setting the end sealant on the right side of the battery core can avoid the overlap of the end sealant and the ear position, thereby effectively reducing the battery core thickness. Calculated according to the PET adhesive tape with an end sealant thickness of 26 microns, the battery thickness can be reduced by 0.026 mm, that is, the thickness can be reduced by 0.51%. In summary, the battery core energy is increased from 4420 mAh to 4696.25 mAh after improvement, effectively increasing the battery capacity by 6.25%, thereby effectively improving the battery energy density.

[0030] It should be noted that the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0031] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A polymer lithium battery capable of improving energy density, comprising a positive electrode sheet, a negative electrode sheet, a separator, a positive electrode tab, a negative electrode tab and a terminal glue. The positive electrode sheet, the negative electrode sheet and the separator are combined into a battery cell of the polymer lithium battery by a winding structure. The separator is disposed between the positive electrode sheet and the negative electrode sheet. The positive electrode tab is disposed on the positive electrode sheet, and the negative electrode tab is disposed on the negative electrode sheet. It is characterized in that: The end sealant is arranged staggered with the positive tab and the negative tab in the width direction of the battery cell. The positive electrode sheet is provided with a slot, and the positive tab is arranged in the slot.

2. The polymer lithium battery capable of improving the energy density according to claim 1, wherein: The slot is located in the double-sided material area at the head of the positive electrode sheet.

3. The polymer lithium battery capable of improving the energy density according to claim 2, characterized in that: The double-sided material area at the head of the positive electrode sheet is formed with the slot by laser cleaning.

4. The polymer lithium battery capable of improving the energy density according to claim 1, characterized in that: One surface of the head of the negative electrode sheet is coated with negative active material and the other surface is not coated with negative active material.

5. The polymer lithium battery capable of enhancing the energy density according to claim 4, wherein: The negative tab is arranged on the other surface of the head of the negative electrode sheet.

6. The polymer lithium battery capable of improving the energy density according to claim 1, characterized in that: The end sealant is located on the right side of the battery cell.

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