Roll core and battery

Abstract

The utility model relates to the technical field of lithium ion batteries, in particular to a roll core and a battery, the roll core comprises a positive pole piece, a negative pole piece, a first diaphragm and a second diaphragm, the first diaphragm, the positive pole piece, the second diaphragm and the negative pole piece are sequentially stacked to form a roll material, and a positive pole area of the positive pole piece extends out of the diaphragm at a positive pole of the roll material; the negative pole region of the negative pole piece extends out of the diaphragm at the negative pole of the coiled material, after the coiled material is coiled into a coiled core, the positive pole lug of the positive pole region can be directly contacted with the positive pole lug-free region after lodging, and the negative pole lug of the negative pole region can also be directly contacted with the negative pole lug-free region after lodging; and compared with the existing form that the positive electrode tab-free area and / or the negative electrode tab-free area do not extend out of the diaphragm, the internal resistance of the battery cell is low, and the battery performance is better.

Description

TECHNICAL FIELD

[0001] The utility model relates to lithium ion battery technical field, concretely relates to a winding core and a battery. BACKGROUND

[0002] Lithium ion batteries are widely used in various power-driven devices due to their high voltage, excellent specific capacity and excellent cycle stability. The performance of the battery is mainly determined by its energy density and power density, and the power density is mainly affected by the battery chemical system and internal structure. For the same chemical system, as the number of pole ears increases, the internal resistance of the battery decreases, and the power density increases. According to the number of pole ears, it is divided into single pole ear, multiple pole ear and full pole ear, and the full pole ear structure performs best in the power battery.

[0003] The full pole ear process difficulty lies in the processing of the pole ear. At present, the die cutting process and the rubbing process are relatively mature. The welding of the pole ear and the current collector disc is directly welded on the current collector disc by laser. The current die cutting has the following disadvantages: the cutting process of the pole piece pretreatment is complex, the die cutting height design is insufficient, the inner circle of the pole ear after shaping is lower than the diaphragm, the pole ear is attached to the diaphragm, the internal resistance of the battery is higher than that of the direct attachment of the pole ear and the foil, and the battery rate performance is affected. UTILITY MODEL CONTENT

[0004] The utility model solves the technical problem to provide a winding core, the positive pole area of positive pole piece and the negative pole area of negative pole piece are exposed to the outside of the diaphragm, so that the pole ear can be directly contacted with the foil in the inner circle of the winding material after the pole ear is flattened, the overall conductivity of the pole group is good, and the resistance is reduced.

[0005] In order to solve the above technical problems, the utility model adopts the following technical scheme: a winding core, comprising a positive pole piece, a negative pole piece, a first diaphragm and a second diaphragm, the first diaphragm, the positive pole piece, the second diaphragm and the negative pole piece are sequentially stacked to form a winding material or the first diaphragm, the negative pole piece, the second diaphragm and the positive pole piece are sequentially stacked to form a winding material, the positive pole piece is provided with a positive pole area, the positive pole area is at the positive pole of the winding material and extends out of the outside of the two diaphragms, the positive pole area comprises a positive pole ear area and a positive pole non-pole ear area on both sides of the positive pole ear area, the positive pole ear area is provided with a positive pole ear, the negative pole piece is provided with a negative pole area, the negative pole area is at the negative pole of the winding material and extends out of the outside of the two diaphragms, the negative pole area comprises a negative pole ear area and a negative pole non-pole ear area on both sides of the negative pole ear area, and the negative pole ear area is provided with a negative pole ear. The positive pole area of the positive pole piece extends out of the diaphragm of the winding material, the negative pole area of the negative pole piece also extends out of the diaphragm of the winding material, after the winding material is wound into a winding core, the positive pole ear directly contacts with the positive pole non-pole ear area after the positive pole ear is inverted to the inner circle, the negative pole ear directly contacts with the negative pole non-pole ear area after the negative pole ear is inverted to the inner circle, compared with the existing form that the positive pole non-pole ear area and / or the negative pole non-pole ear area does not extend out of the diaphragm, the internal resistance of the battery is low, and the battery performance is better.

[0006] As an optional solution, the two positive tab-free areas are an inner circle positive tab-free area and an outer circle positive tab-free area, and the inner circle positive tab-free area, the positive tab area and the outer circle positive tab-free area are distributed along the winding edge of the winding material; the two negative tab-free areas are an inner circle negative tab-free area and an outer circle negative tab-free area, and the inner circle negative tab-free area, the negative tab area and the outer circle negative tab-free area are distributed along the winding edge of the winding material.

[0007] Based on the same concept, the utility model also provides a kind of battery, uses the winding core described above, and battery performance is better.

[0008] Compared with prior art, the utility model has the beneficial effects that: the winding core of the utility model, the positive area of the positive tab, especially the positive tab-free area, extends out of the diaphragm, the negative area of the negative tab, especially the negative tab-free area, also extends out of the diaphragm, after winding and forming the winding core, the positive tab ear can contact the positive tab-free area, and the negative tab ear can contact the negative tab-free area, so that the resistance of the battery is small, the current transmission efficiency is improved, the battery rate performance is good by using the battery, and the direct contact of the tab and the tab foil can reduce the loss caused by poor contact or excessive contact resistance of the battery in long-term use, avoid the performance degradation phenomenon in the battery aging process, thereby prolonging the service life of the battery BRIEF DESCRIPTION OF DRAWINGS

[0009] In order to more clearly illustrate the technical scheme in the embodiment of the utility model or prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and those skilled in the art can obtain other drawings according to these drawings without creating labor.

[0010] Figure 1 It is a structural schematic diagram of winding material;

[0011] Figure 2 It is a structural schematic diagram of positive tab;

[0012] Figure 3 It is a structural schematic diagram of negative tab;

[0013] Figure 4 It is a sectional view schematic diagram of winding material after winding into winding core;

[0014] Figure 5 It is a sectional view schematic diagram of winding material after winding into winding core;

[0015] Figure 6 It is a comparison schematic diagram of tested ACR;

[0016] Figure 7A schematic diagram of the DCR for testing;

[0017] In the figure: 1, positive electrode sheet, 11, positive electrode tab area, 12, inner circle positive electrode tab-free area, 13, outer circle positive electrode tab-free area, 2, negative electrode sheet, 21, negative electrode tab area, 22, inner circle negative electrode tab-free area, 23, outer circle negative electrode tab-free area, 3, first separator, 4, second separator. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.

[0019] Embodiment 1

[0020] Please refer to Figures 1-5 A roll core, comprising a positive electrode sheet 1, a negative electrode sheet 2, a first separator 3 and a second separator 4, the first separator 3, the positive electrode sheet 1, the second separator 4 and the negative electrode sheet 2 are sequentially stacked to form a roll material, and the upper edge and the lower edge of the roll material are both winding edges, Figure 1 A schematic diagram of the structure in the unwound state of the roll material, the end part where the upper edge of the roll material is located is the positive electrode, the end part where the lower edge of the roll material is located is the negative electrode, and the roll material is wound along the winding edges to form a roll core, at this time, the upper end of the roll core is the positive electrode and the lower end is the negative electrode, Figure 4 And Figure 5 A schematic diagram of the cross section of the roll core after the roll material is wound into the roll core. In some embodiments, the roll material can also be sequentially stacked by the first separator 3, the negative electrode sheet 2, the second separator 4 and the positive electrode sheet 1.

[0021] Please refer to Figure 1 , Figure 2 , Figure 4 And Figure 5 The positive electrode sheet 1 is provided with a positive electrode area, the positive electrode area is at the positive electrode of the roll material and extends outside the two separators, the positive electrode area extends outside the roll core after the roll material is wound to form the roll core, the positive electrode area comprises a positive electrode tab area 11 and a positive electrode tab-free area, the positive electrode tab-free area is provided with two, and along the length direction of the upper winding edge of the roll material, the two positive electrode tab-free areas are respectively on the two sides of the positive electrode tab area 11, and the positive electrode tab area 11 is provided with a positive electrode tab.

[0022] Please refer to Figure 1 , Figure 3 , Figure 4 And Figure 5The negative electrode tab 2 is provided with a negative electrode area, the negative electrode area is at the negative electrode of the coiled material and extends outside the two separators, after the coiled material is coiled to form a core, the negative electrode area extends outside the core, the negative electrode area includes a negative electrode tab area 21 and a negative electrode tab-free area, the negative electrode tab-free area is provided with two, and along the length direction of the lower coiled edge of the coiled material, the two negative electrode tab-free areas are respectively at the two sides of the negative electrode tab area 21, and the negative electrode tab-free area is provided with a negative electrode tab.

[0023] The two positive electrode tab-free areas are respectively an inner ring positive electrode tab-free area 12 and an outer ring positive electrode tab-free area 13, and the two negative electrode tab-free areas are respectively an inner ring negative electrode tab-free area 22 and an outer ring negative electrode tab-free area 23, the inner ring positive electrode tab-free area 12, the positive electrode tab area 11 and the outer ring positive electrode tab-free area 13 are sequentially distributed along the coiled edge direction of the coiled material, the inner ring negative electrode tab-free area 22, the negative electrode tab area 21 and the outer ring negative electrode tab-free area 23 are distributed along the coiled edge of the coiled material, the inner ring positive electrode tab-free area 12 corresponds to the inner ring negative electrode tab-free area 22 in position, and the outer ring positive electrode tab-free area 13 corresponds to the outer ring negative electrode tab-free area 23 in position, after the coiled material is coiled to form a core, the inner ring positive electrode tab-free area 12 and the inner ring negative electrode tab-free area 22 are both located in the inner ring of the core, and the outer ring positive electrode tab-free area 13 and the outer ring negative electrode tab-free area 23 are both located in the outer ring of the core.

[0024] After the coiled material is coiled to form a core, the positive electrode tab area 11 and the positive electrode tab-free area of the positive electrode tab 1 both extend outside the separator, and the negative electrode tab area 21 and the negative electrode tab-free area of the negative electrode tab 2 also both extend outside the separator, after the positive electrode tab and the negative electrode tab are flattened, the positive electrode tab can directly contact the inner ring positive electrode tab-free area 12, and the negative electrode tab can directly contact the foil of the inner ring negative electrode tab-free area 22, the conductivity of the core group is good, and the resistance is low. The positive electrode tab-free area of the positive electrode tab 1 and / or the negative electrode tab-free area of the negative electrode tab 2 cannot extend outside the separator, and after the positive electrode tab and / or the negative electrode tab are flattened, they contact the separator, the conductivity of the separator is poor, and the overall conductivity of the group is relatively low, and the resistance is larger.

[0025] The following are the test data of the present embodiment, after the above-mentioned core is divided into containers, AC resistance test and DC resistance test are carried out, wherein M represents the test data of the core of the present embodiment, M1 and M2 are control products, M1 represents the test data of the core in which the inner ring positive electrode tab-free area 12 does not extend outside the separator, and M2 represents the test data of the core in which the inner ring positive electrode tab-free area 12 and the inner ring negative electrode tab-free area 22 do not extend outside the separator, Figure 6 is a comparison diagram of the results of AC resistance test (ACR), Figure 7 is a comparison diagram of the results of DC resistance test (DCR), and Figure 6 and Figure 7The results can indicate that the ACR of the core of the embodiment is minimum, the positive lug directly adheres to the inner circle positive tab area 12 of the positive tab 1 after the positive lug is bent inward, the negative lug directly adheres to the inner circle negative tab area 22 of the negative tab 2 after the negative lug is bent inward, compared with the adhesion of the diaphragm, the resistance is smaller, which means that the resistance of current transmission is small, the current transmission efficiency is improved, and the rate performance is good. The direct contact of the lug and the foil of the tab can reduce the loss caused by poor contact or excessive contact resistance of the battery in long-term use, avoid the performance degradation phenomenon in the battery aging process, thereby prolonging the service life of the battery.

[0026] Embodiment 2

[0027] On the basis of embodiment 1, the battery of the present embodiment adopts the core of embodiment 1.

[0028] In the description of the present specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0029] The above is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this. Any skilled person in the art can make equivalent replacement or change according to the technical scheme and the application concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A core, characterized by: The battery includes a positive electrode sheet (1), a negative electrode sheet (2), a first separator (3), and a second separator (4). The first separator (3), the positive electrode sheet (1), the second separator (4), and the negative electrode sheet (2) are sequentially stacked to form a roll or the first separator (3), the negative electrode sheet (2), the second separator (4), and the positive electrode sheet (1) are sequentially stacked to form a roll. The positive electrode sheet (1) is provided with a positive electrode area. The positive electrode area is at the positive electrode of the roll and extends outside the two separators. The positive electrode area includes a positive electrode tab area (11) and a positive electrode tab-free area on both sides of the positive electrode tab area (11). The positive electrode tab area (11) is provided with a positive electrode tab. The negative electrode sheet (2) is provided with a negative electrode area. The negative electrode area is at the negative electrode of the roll and extends outside the two separators. The negative electrode area includes a negative electrode tab area (21) and a negative electrode tab-free area on both sides of the negative electrode tab area (21). The negative electrode tab area (21) is provided with a negative electrode tab.

2. A core according to claim 1, characterised in that: The two positive electrode tab-free areas are an inner ring positive electrode tab-free area (12) and an outer ring positive electrode tab-free area (13). The inner ring positive electrode tab-free area (12), the positive electrode tab area (11), and the outer ring positive electrode tab-free area (13) are distributed along the winding edge of the roll. The two negative electrode tab-free areas are an inner ring negative electrode tab-free area (22) and an outer ring negative electrode tab-free area (23). The inner ring negative electrode tab-free area (22), the negative electrode tab area (21), and the outer ring negative electrode tab-free area (23) are distributed along the winding edge of the roll.

3. A battery, characterized by: The battery includes the roll core of claim 1 or 2.

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