Bare battery cell prefabricated structure, bare battery cell and battery

Abstract

The utility model discloses a bare cell prefabricated structure which comprises a prefabricated unit, and the prefabricated unit is provided with a first length direction, a first width direction and a first thickness direction which are vertical in pairs; the prefabrication unit comprises a positive plate belt, diaphragm belts and a negative plate belt which are sequentially stacked in the first thickness direction, and the diaphragm belts are stacked on the two sides of the positive plate belt or the negative plate belt; in the first length direction, the positive plate belt comprises positive tab areas which are arranged at intervals, and the negative plate belt comprises negative tab areas which are arranged at intervals; in the first thickness direction, the positive plate belt comprises a positive gap corresponding to the negative tab area, and the negative plate belt comprises a negative gap corresponding to the positive tab area; the positive tab areas and the negative tab areas are arranged at intervals in the first length direction or the first width direction, and the diaphragm belt is provided with diaphragm gaps corresponding to the positive tab areas and the negative tab areas one by one. The utility model can improve the quality of the battery. The utility model also discloses a naked battery cell and a battery.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a prefabricated structure of a bare battery cell, a bare battery cell and a battery. Background Art

[0002] At present, square lithium batteries are developing towards large sizes, with a relatively long length. To avoid deformation of the opening length of the housing or the length of the cover plate, which may affect the sealing welding quality, a cover plate is usually provided at the end of the battery in the length direction.

[0003] The bare battery cell inside the battery can be a stacked bare battery cell or a wound bare battery cell. Among them, winding has the advantage of high production efficiency compared with stacking.

[0004] When a wound bare battery cell is selected, the length direction of the flat wound bare battery cell in the square battery is usually parallel to the length direction of the battery. To improve the electrolyte infiltration efficiency, the length direction of the bare battery cell needs to be perpendicular to the direction where its winding axis is located. However, in the prior art in this case, the tab area will be provided at the end of the bare battery cell along the direction where the winding axis is located. Thus, a connecting piece needs to be used to connect the conductive terminal of the cover plate with the tab area of the bare battery cell. Since the connecting piece provided in this structure is affected by the relatively small thickness of the battery housing and is relatively narrow, the internal resistance of the battery will increase, affecting the battery performance. Summary of the Utility Model

[0005] In order to overcome the disadvantages and deficiencies in the prior art, the purpose of the utility model is to provide a prefabricated structure of a bare battery cell, a bare battery cell and a battery, to solve the problem that the tab area of the existing wound battery cell can only be provided at the end along the direction where the winding axis is located, and to balance the problems of infiltration efficiency, welding quality between the cover plate and the housing of the finished square battery, and the internal resistance of the battery, so as to improve the battery quality.

[0006] The purpose of the utility model is achieved by the following technical solutions:

[0007] A prefabricated structure of a bare battery cell includes a prefabricated unit. The prefabricated unit has a first length direction, a first width direction and a first thickness direction that are perpendicular to each other. The prefabricated unit includes a positive electrode strip, a separator strip and a negative electrode strip that are stacked in sequence in the first thickness direction. Among them, separator strips are stacked on both sides of the positive electrode strip or the negative electrode strip. In the first length direction, the positive electrode strip includes spaced-apart positive tab areas, and the negative electrode strip includes spaced-apart negative tab areas. In the first thickness direction, the positive electrode strip includes positive notches corresponding to the negative tab areas, and the negative electrode strip includes negative notches corresponding to the positive tab areas. The positive tab areas and the negative tab areas are spaced apart in the first length direction or the first width direction, and the separator strip is provided with separator notches corresponding to the positive tab areas and the negative tab areas one by one.

[0008] In one embodiment, the positive tab regions and the positive notches are arranged alternately in the first length direction; in the first length direction, the size of the positive tab region is a1, the size of the adjacent negative tab region is b1, the distance between the positive tab region and the adjacent negative tab region is c1, and the size of the separator strip in the first width direction is d1; 0.5a1 + 0.5b1 + c1 ≥ d1.

[0009] In one embodiment, the positive tab regions and the positive notches are arranged side by side in the first width direction; in the first length direction, the sizes of two adjacent positive tab regions are a2 and a3 respectively, the sizes of the corresponding two adjacent negative tab regions are b2 and b3 respectively, the distance between two adjacent positive tab regions is c2, and the distance between two adjacent negative tab regions is c3; 0.5a2 + c2 + 0.5a3 = 0.5b2 + c3 + 0.5b3.

[0010] In one embodiment, in the first thickness direction, among the negative notches and the separator notches corresponding to the positive tab regions, the edge of the negative notch overlaps with the edge of the separator notch or is covered by the separator strip; in the first thickness direction, among the positive notches and the separator notches corresponding to the negative tab regions, the edge of the positive notch overlaps with the edge of the separator notch or is covered by the separator strip.

[0011] In one embodiment, the prefabricated unit includes a winding start point and a winding end point at both ends in the first length direction. From the winding start point to the winding end point, the distance between adjacent separator notches in the first length direction gradually increases.

[0012] In one embodiment, the positive tab regions and the positive notches are arranged side by side in the first width direction; in the first length direction, the sizes of two adjacent positive tab regions are a2 and a3 respectively, the distance between two adjacent positive tab regions is c2, the size of the separator strip in the first width direction is d2, 0.5a2 + c2 + 0.5a3 ≥ d2 or 0.5a2 + c2 + 0.5a3 ≥ 2d2.

[0013] In one embodiment, 0.5a2 + c2 + 0.5a3 ≥ 2d2; in the first length direction, the positive tab strip includes alternately arranged positive coating regions and positive bare foil regions, the positive tab regions and the positive notches are both located in the positive bare foil regions, the negative tab strip includes alternately arranged negative coating regions and negative bare foil regions, and the negative tab regions and the negative notches are both located in the negative bare foil regions; a positive bare foil region is further provided between two adjacent positive tab regions of the positive tab strip, and a negative bare foil region is further provided between two adjacent negative tab regions of the negative tab strip.

[0014] In one embodiment, in the first length direction, the positive electrode sheet strip includes alternately arranged positive electrode coating regions and positive electrode bare foil regions, the positive electrode tab region and the positive electrode notch are both located in the positive electrode bare foil region, the negative electrode sheet strip includes alternately arranged negative electrode coating regions and negative electrode bare foil regions, and the negative electrode tab region and the negative electrode notch are both located in the negative electrode bare foil region.

[0015] In one embodiment, in the first length direction, each of the positive electrode coating regions has the same length, and each of the negative electrode coating regions has the same length.

[0016] The present utility model also provides a bare battery cell, which is wound from the bare battery cell prefabricated structure as described above, the winding direction is perpendicular to the winding axis direction, the winding axis direction is parallel to the first width direction, and the positive electrode tab region, the positive electrode notch, the negative electrode tab region, the negative electrode notch, and the separator notch are all located at the turning point of the bare battery cell.

[0017] In one embodiment, the size of the bare battery cell in the first length direction is greater than its size in the first width direction.

[0018] The present utility model also provides a battery, which includes a cover plate, a housing, and the bare battery cell as described above. The long side of the housing is parallel to the first length direction, the cover plate is arranged at the end of the housing along the first length direction, the bare battery cell is located inside the housing, the cover plate is provided with a positive conductive terminal and a negative conductive terminal, and the bare battery cell is electrically connected to the positive conductive terminal through the positive electrode tab region and electrically connected to the negative conductive terminal through the negative electrode tab region.

[0019] The beneficial effects of the present utility model are as follows: When winding, the direction where the winding axis is located is parallel to the first width direction, so that the positive electrode tab region and the negative electrode tab region are located at the winding turning point of the finally formed flat wound battery cell. The positive electrode tab region and the negative electrode tab region are spaced apart in the first length direction or the first width direction. The positive electrode sheet strip is provided with a positive electrode notch, the negative electrode sheet strip is provided with a negative electrode notch, and the separator strip is provided with a separator notch. In this way, the tab region of the wound battery cell can be arranged at the winding turning point. Subsequently, through size design, it can be realized that the length direction of the bare battery cell is parallel to the first length direction and perpendicular to the direction where the winding axis is located, and at the same time, the tab region is arranged at the end of the bare battery cell along the first length direction. Therefore, the produced battery can take into account the production efficiency, infiltration efficiency, welding quality of the cover plate and the housing of the finished battery, and the internal resistance of the battery, improving the quality of the battery. Description of the Drawings

[0020] To more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present utility model, and thus should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0021] Figure 1 is a schematic structural diagram of the positive and negative electrode strip of an embodiment of the present utility model;

[0022] Figure 2 corresponds to Figure 1 is a schematic structural diagram of the separator strip;

[0023] Figure 3a is Figure 1 and Figure 2 is a schematic diagram of a prefabricated unit method that has not been stacked;

[0024] Figure 3b is Figure 1 and Figure 2 is a schematic diagram of another prefabricated unit method that has not been stacked;

[0025] Figure 4 is Figure 1 and Figure 2 is a schematic structural diagram of a bare battery cell formed after stacking;

[0026] Figure 5 is Figure 4 is a schematic structural diagram of the positive and negative transfer sheets connected;

[0027] Figure 6 is a schematic structural diagram of the positive and negative electrode strip of another embodiment of the present utility model;

[0028] Figure 7 corresponds to Figure 6 is a schematic structural diagram of the separator strip;

[0029] Figure 8a is Figure 6 and Figure 7 is a schematic diagram of a prefabricated unit method that has not been stacked;

[0030] Figure 8b is Figure 6 and Figure 7 is a schematic diagram of another prefabricated unit method that has not been stacked;

[0031] Figure 9 is Figure 6 and Figure 7 is a schematic structural diagram of another bare battery cell formed after stacking;

[0032] Figure 10 It is a schematic structural diagram of the positive and negative electrode strip of another embodiment of the present utility model;

[0033] Figure 11 is Figure 10 A schematic structural diagram of another bare battery cell formed after stacking with the corresponding separator strip.

[0034] In the figure: 100, bare battery cell; 1, prefabricated unit; 11, positive electrode strip; 111, positive electrode coating area; 112, positive electrode bare foil area; 113, positive electrode tab area; 114, positive electrode notch; 12, negative electrode strip; 121, negative electrode coating area; 122, negative electrode bare foil area; 123, negative electrode tab area; 124, negative electrode notch; 13, separator strip; 131, separator notch; 2, positive adapter piece; 3, negative adapter piece; 4, turning point. Specific embodiments

[0035] Next, specific embodiments of the present utility model will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the description of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

[0036] In the description of the present utility model, unless otherwise clearly defined and limited, terms such as "set", "installed", "connected", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific situations.

[0037] The orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present utility model is usually placed during use. It is only for the convenience of description and simplification of the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model.

[0038] Terms such as "first", "second", "third", etc. are only used to distinguish elements with similar attributes, rather than indicating or implying relative importance or a specific order.

[0039] The term "comprises", "comprising" or any other variant thereof is intended to cover a non-exclusive inclusion, including not only those listed elements, but also other elements not specifically listed.

[0040] The present utility model provides a prefabricated structure for a bare battery cell, as Figures 1 to 11 shown, comprising a prefabricated unit 1. The prefabricated unit 1 has a first length direction L1, a first width direction W1, and a first thickness direction D1 that are perpendicular to each other in pairs; the prefabricated unit 1 includes a positive electrode strip 11, a separator strip 13, and a negative electrode strip 12 that are stacked in sequence in the first thickness direction D1. Among them, separator strips 13 are stacked on both sides of the positive electrode strip 11 or the negative electrode strip 12 to prevent the positive electrode strip 11 and the negative electrode strip 12 from directly contacting and short-circuiting when the bare battery cell 100 is formed by winding; in the first length direction L1, the positive electrode strip 11 includes positive electrode tab regions 113 arranged at intervals, and the negative electrode strip 12 includes negative electrode tab regions 123 arranged at intervals; in the first thickness direction D1, the positive electrode strip 11 includes positive electrode notches 114 corresponding to the negative electrode tab regions 123, and the negative electrode strip 12 includes negative electrode notches 124 corresponding to the positive electrode tab regions 113; the positive electrode tab regions 113 and the negative electrode tab regions 123 are arranged at intervals in the first length direction L1 or the first width direction W1, and the separator strip 13 is provided with separator notches 131 corresponding to the positive electrode tab regions 113 and the negative electrode tab regions 123 respectively. Among them, the prefabricated unit 1 includes a plurality of positive electrode tab regions 113 and a plurality of negative electrode tab regions 123, and the positive electrode tab regions 113 and the negative electrode tab regions 123 are arranged at intervals in the first length direction L1, and specifically can be arranged into a prefabricated unit 1 in which the positive electrode tab regions 113 and the negative electrode tab regions 123 alternate along the first length direction L1 as Figures 3a to 3b shown; the positive electrode tab regions 113 and the negative electrode tab regions 123 are arranged at intervals in the first width direction W1, and specifically can be arranged into a prefabricated unit 1 in which a plurality of positive electrode tab regions 113 are arranged at intervals along the first length direction L1, a plurality of negative electrode tab regions 123 are arranged at intervals along the first length direction L1, a plurality of positive electrode tab regions 113 are arranged on one side of the plurality of negative electrode tab regions 123 along the first width direction W1, the positive electrode tab regions 113 and the negative electrode tab regions 123 correspond to each other one by one, and the positive electrode tab region 113 and its corresponding negative electrode tab region 123 are arranged along the first width direction W1 as Figures 8a to 8b shown.

[0041] In this embodiment, when winding, the direction of the winding shaft is parallel to the first width direction W1, and the positive tab area 113 and the negative tab area 123 are located at the winding turning point 4 of the finally formed bare battery cell 100 (flat wound battery cell). The positive tab area 113 and the negative tab area 123 are spaced apart in the first length direction L1 or the first width direction W1. The positive electrode strip 11 is provided with a positive electrode notch 114, the negative electrode strip 12 is provided with a negative electrode notch 124, and the separator strip 13 is provided with a separator notch 131. In this way, the tab area of the wound battery cell can be arranged at the winding turning point 4. Subsequently, through dimensional design, it can be achieved that the length direction L of the bare battery cell 100 is parallel to the first length direction L1 and perpendicular to the direction of the winding shaft, and at the same time, the tab area is arranged at the end of the bare battery cell 100 along the first length direction L1. Thus, the produced battery can take into account production efficiency, infiltration efficiency, the welding quality of the cover plate (not shown) and the housing (not shown) of the finished battery, and the internal resistance of the battery, improving the quality of the battery.

[0042] Specifically, the prefabrication unit 1 includes a positive electrode strip 11, a separator strip 13, and a negative electrode strip 12 stacked in sequence in the first thickness direction D1. When the separator strip 13 is stacked on both sides of the positive electrode strip 11 or the negative electrode strip 12, it can be stacked in the manner as Figure 3a Or Figure 3b To form a prefabrication unit 1. After one prefabrication unit 1 or multiple prefabrication units 1 with the same stacking method are stacked in the first thickness direction D1, they are wound along a winding shaft parallel to the first width direction W1, and the positive tab area 113, the positive electrode notch 114, the negative tab area 123, the negative electrode notch 124, and the separator notch 131 can all be located at the turning point 4. After winding, as Figure 4 Shown, the positive tab area 113 and the negative tab area 123 are located at the winding turning point 4 of the finally formed bare battery cell 100 (flat wound battery cell); as Figure 5 Shown, a positive adapter piece 2 is arranged at the positive tab area 113, and a negative adapter piece 3 is arranged at the negative tab area 123. The positive adapter piece 2 is connected to the positive conductive terminal (not shown) on the cover plate, and the negative adapter piece 3 is connected to the negative conductive terminal (not shown) on the cover plate. In this solution, the adapter piece will not be too narrow due to the small thickness of the battery housing, and thus will not have a great impact on the internal resistance of the battery.

[0043] As an implementation manner, as Figure 1 Shown, the positive tab area 113 and the positive electrode notch 114 are alternately arranged in the first length direction L1; thus, the negative tab area 123 and the negative electrode notch 124 are also alternately arranged in the first length direction L1, so that in the first thickness direction D1, the positive tab area 113 and the negative electrode notch 124 correspond one by one, and the negative tab area 123 and the positive electrode notch 114 correspond one by one; realizing the spaced and alternating arrangement of the positive tab area 113 and the negative tab area 123 in the first length direction L1.

[0044] As an implementation manner, as Figures 1 to 4 shown, the positive electrode tab area 113 and the positive electrode notch 114 are arranged alternately in the first length direction L1. In the first length direction L1, the size of the positive electrode tab area 113 is a1, the size of the adjacent negative electrode tab area 123 is b1, the distance between the positive electrode tab area 113 and the adjacent negative electrode tab area 123 is c1, and the size of the separator tape 13 in the first width direction W1 is d1; 0.5a1 + 0.5b1 + c1 ≥ d1. In the first width direction W1, the size of the separator tape 13 used to separate the positive electrode sheet tape 11 and the negative electrode sheet tape 12 is greater than or equal to the size of the positive electrode sheet tape 11 or the negative electrode sheet tape 12, and the size of the bare battery cell 100 in the first width direction W1 is also the size d1 of the separator tape 13 in the first width direction W1. In this implementation manner, in the first length direction L1, the wound bare battery cell 100 turns at the middle of the positive electrode tab area 113 or the middle of the negative electrode tab area 123. When 0.5a1 + 0.5b1 + c1 ≥ d1, the size of the finally wound bare battery cell 100 in the first length direction L1 is greater than its size in the first width direction W1. Thus, the positive electrode tab area 113 or the negative electrode tab area 123 is arranged at the end of the length direction L where the longer outer dimension of the bare battery cell 100 is located, and the length direction L of the bare battery cell 100 is perpendicular to the direction where the winding axis is located.

[0045] As an implementation manner, as Figure 6 , Figure 9 and Figure 11 shown, the positive electrode tab area 113 and the corresponding positive electrode notch 114 are arranged side by side in the first width direction W1; thus, the negative electrode tab area 123 and the corresponding negative electrode notch 124 are also arranged side by side in the first width direction W1, so that in the first thickness direction D1, the positive electrode tab area 113 and the negative electrode notch 124 correspond one by one, and the negative electrode tab area 123 and the positive electrode notch 114 correspond one by one; realizing that the positive electrode tab area 113 and the corresponding negative electrode tab area 123 are arranged side by side in the first width direction W1. In this implementation manner, the positive electrode tab area 113 and the negative electrode tab area 123 can be arranged at the same end of the bare battery cell 100 along the first length direction L1.

[0046] As an implementation manner, as Figures 6 to 11 shown, the positive electrode tab area 113 and the corresponding positive electrode notch 114 are arranged side by side in the first width direction W1. In the first length direction L1, the sizes of two adjacent positive electrode tab areas 113 are a2 and a3 respectively, the sizes of the corresponding two adjacent negative electrode tab areas 123 are b2 and b3 respectively, the distance between two adjacent positive electrode tab areas 113 is c2, and the distance between two adjacent negative electrode tab areas 123 is c3; 0.5a2 + c2 + 0.5a3 = 0.5b2 + c3 + 0.5b3.

[0047] As an implementation manner, in the first thickness direction D1, in the negative electrode notch 124 and the separator notch 131 corresponding to the positive electrode tab area 113, the edge of the negative electrode notch 124 overlaps with the edge of the separator notch 131 or is covered by the separator strip 13; in the first thickness direction D1, in the positive electrode notch 114 and the separator notch 131 corresponding to the negative electrode tab area 123, the edge of the positive electrode notch 114 overlaps with the edge of the separator notch 131 or is covered by the separator strip 13. In this example, the size of the separator notch 131 is greater than or equal to the sizes of the positive electrode notch 114 and the negative electrode notch 124. The negative electrode notch 124 can completely cover the corresponding separator notch 131 along the first thickness direction D1, and the positive electrode notch 114 can completely cover the corresponding separator notch 131 along the first thickness direction D1, avoiding short circuit caused by the contact between the positive electrode strip 11 and the negative electrode strip 12 through the separator notch 131.

[0048] As an implementation manner, the prefabricated unit 1 includes a winding start point and a winding end point at both ends in the first length direction L1. From the winding start point to the winding end point, the distance between adjacent separator notches 131 in the first length direction L1 gradually increases to adapt to the situation that the circumference of the winding turns increases from the inside to the outside.

[0049] As an implementation manner, as Figures 6 to 11 shown, the positive electrode tab area 113 and the positive electrode notch 114 are arranged side by side in the first width direction W1; in the first length direction L1, the sizes of two adjacent positive electrode tab areas 113 are a2 and a3 respectively, the distance between two adjacent positive electrode tab areas 113 is c2, the size of the separator strip 13 in the first width direction W1 is d2, and 0.5a2 + c2 + 0.5a3 ≥ d2 or 0.5a2 + c2 + 0.5a3 ≥ 2d2. The sizes of two corresponding adjacent negative electrode tab areas 123 are b2 and b3 respectively, and the distance between two adjacent negative electrode tab areas 123 is c3; similarly, 0.5b2 + c3 + 0.5b3 ≥ d2 or 0.5b2 + c3 + 0.5b3 ≥ 2d2. Among them, because the outer winding circle has a longer circumference than the inner circle, a2 is not necessarily equal to a3, and b2 is not necessarily equal to b3.

[0050] Specifically, when 0.5a2 + c2 + 0.5a3 ≥ d2, the positive electrode strip 11, the separator strip 13, and the negative electrode strip 12 stacked in sequence in the first thickness direction D1 are stacked according to Figure 8a or Figure 8b After stacking to form the prefabricated unit 1, winding is carried out to form a bare battery cell 100 as shown in Figure 9 shown. The bare battery cell 100 turns at the positive electrode tab area 113 or the negative electrode tab area 123. Both opposite sides of the bare battery cell 100 along the first length direction L1 are provided with the positive electrode tab area 113 and the negative electrode tab area 123, and the length direction L of the bare battery cell 100 is perpendicular to the direction where the winding axis is located.

[0051] When 0.5a2 + c2 + 0.5a3 ≥ 2d2, after the positive and negative electrode strips are stacked with the corresponding separator strip 13, they are wound according to the above method to obtain a bare battery cell 100 as shown in Figure 11 Figure 100. One side of the bare battery cell 100 along the length direction L is provided with a positive electrode tab area 113 and a negative electrode tab area 123, and the length direction L of the bare battery cell 100 is perpendicular to the direction where the winding axis is located.

[0052] As an implementation manner, as shown in Figure 1 , Figure 4 , Figure 6 and Figure 9 Figure 100, on the first length direction L1, the positive electrode strip 11 includes alternately arranged positive electrode coating areas 111 and positive electrode bare foil areas 112. The positive electrode tab area 113 and the positive electrode notch 114 are both located in the positive electrode bare foil area 112. The negative electrode strip 12 includes alternately arranged negative electrode coating areas 121 and negative electrode bare foil areas 122. The negative electrode tab area 123 and the negative electrode notch 124 are both located in the negative electrode bare foil area 122. Among them, both the positive electrode tab area 113 and the negative electrode tab area 123 are at the turning point 4 of the winding. In this implementation manner, the positive electrode strip 11 turns at the uncoated and thinner positive electrode bare foil area 112, and the negative electrode strip 12 turns at the uncoated and thinner negative electrode bare foil area 122, which is convenient for winding and relieves the stress influence at the turning point 4, facilitates the shaping of the bare battery cell 100, and relieves the problem of lithium deposition due to uneven positive and negative electrode matching at the turning point of traditional wound battery cells.

[0053] As an implementation manner, when the positive electrode tab area 113 and the corresponding positive electrode notch 114 are arranged side by side in the first width direction W1 and 0.5a2 + c2 + 0.5a3 ≥ 2d2, on the first length direction L1, an uncoated positive electrode bare foil area 112 is further provided between adjacent positive electrode tab areas 113 of the positive electrode strip 11, and an uncoated negative electrode bare foil area 122 is further provided between adjacent negative electrode tab areas 123 of the negative electrode strip 12. In this implementation manner, the formed bare battery cell 100 can be provided with a positive electrode tab area 113 and a negative electrode tab area 123 only on one side in the first length direction L1, and the turning point 4 of the bare battery cell 100 is not coated, which is convenient for winding and relieves the stress influence at the turning point 4, facilitates the shaping of the bare battery cell 100, and relieves the problem of lithium deposition due to uneven positive and negative electrode matching at the turning point of traditional wound battery cells.

[0054] As an implementation manner, as shown in Figure 1 and Figure 6 Figure 100, on the first length direction L1, each positive electrode coating area 111 has the same length, and each negative electrode coating area 121 has the same length. After winding, each positive electrode coating area 111 has the same length in the first length direction L1, and each negative electrode coating area 121 has the same length in the first length direction L1.

[0055] As an implementation manner, the bare cell prefabricated structure includes at least one prefabricated unit 1. When there are multiple prefabricated units 1, the prefabricated units 1 with the same stacking manner are stacked along the first thickness direction D1.

[0056] As an implementation manner, the positive tab area 113 and the negative tab area 123 of the prefabricated unit 1 can also be alternately arranged in the first length direction L1 and spaced in the first width direction W1, so as to form a bare cell 100 in which the positive tab area 113 and the negative tab area 123 are located on opposite sides along the first length direction L1 and spaced in the first width direction W1.

[0057] The present utility model also provides a bare cell 100, as Figures 1 to 11 shown, which is wound from the above-mentioned bare cell prefabricated structure. The winding direction is perpendicular to the direction where the winding axis is located, the direction where the winding axis is located is parallel to the first width direction W1, and the positive tab area 113, the positive notch 114, the negative tab area 123, the negative notch 124, and the separator notch 131 are all located at the turning point 4 of the bare cell 100.

[0058] As an implementation manner, as Figure 4 、 Figure 9 and Figure 11 shown, the size of the bare cell 100 in the first length direction L1 is greater than its size in the first width direction W1.

[0059] The present utility model also provides a battery, which includes a cover plate (not shown), a housing (not shown), and the above-mentioned bare cell 100. The long side of the housing is parallel to the first length direction L1. The housing is a hollow cavity structure with one end open, and the opening is located at one end along the first length direction L1. The cover plate is arranged at the opening at the end of the housing along the first length direction L1 and can open or close the housing. The bare cell 100 is located inside the housing. The cover plate is provided with a positive conductive terminal (not shown) and a negative conductive terminal (not shown). The bare cell 100 is electrically connected to the positive conductive terminal through the positive tab area 113, and the bare cell 100 is electrically connected to the negative conductive terminal through the negative tab area 123.

[0060] As an implementation manner, as Figure 5 shown, the positive tab area 113 is connected to the positive conductive terminal through a positive adapter piece 2, and the negative tab area 123 is connected to the negative conductive terminal through a negative adapter piece 3.

[0061] For the bare cell 100 (wound cell) of the present utility model, the tab areas (positive tab area 113 and negative tab area 123) can be arranged at the ends of the wound cell perpendicular to the direction where the winding axis is located. Thus, the produced battery can take into account the production efficiency, the infiltration efficiency, the welding quality of the cover plate and the housing of the finished battery, and the internal resistance of the battery, improving the quality of the battery.

[0062] The present utility model also provides a method for manufacturing a bare battery cell, which is applied to a prefabricated structure of a bare battery cell and includes:

[0063] Step 1, the step of manufacturing the pole piece tape: manufacture a positive pole piece tape 11 and a negative pole piece tape 12, and obtain a positive pole piece tape 11 that is at least not coated in the positive pole tab area 113, and a negative pole piece tape 12 that is at least not coated in the negative pole tab area 123;

[0064] Step 2, the cutting step: cut the positive pole piece tape 11, the negative pole piece tape 12, and the separator tape 13, cut a positive notch 114 on the positive pole piece tape 11, cut a negative notch 124 on the negative pole piece tape 12, and cut a separator notch 131 on the separator tape 13;

[0065] Step 3, the stacking step: stack a prefabricated unit 1 in the order of the positive pole piece tape 11, the separator tape 13, the negative pole piece tape 12, and the separator tape 13 in the first thickness direction D1, or stack a prefabricated unit 1 in the order of the separator tape 13, the positive pole piece tape 11, the separator tape 13, and the negative pole piece tape 12; the positive pole tab area 113 is stacked with the corresponding negative notch 124 and the corresponding separator notch 131 in the first thickness direction D1, and the negative pole tab area 123 is stacked with the corresponding positive notch 114 and the corresponding separator notch 131 in the first thickness direction D1;

[0066] Step 4, the winding step: wind the prefabricated structure of the bare battery cell composed of the prefabricated unit 1 around a winding shaft parallel to the first width direction W1, and make both the positive pole tab area 113 and the negative pole tab area 123 located at the winding turning point 4 of the flat bare battery cell 100.

[0067] Among them, in step 4, the wound Figure 4 、 Figure 9 or Figure 11 bare battery cell 100.

[0068] As an implementation manner, in step 2, a laser or a metal knife die is used to cut the positive notch 114 and the negative notch 124; a hot cutting knife is used to cut the separator notch 131.

[0069] The above is only a preferred embodiment of the present utility model, and does not make any form of limitation to the present utility model. Although the present utility model has been disclosed above with the preferred embodiment, it is not used to limit the present utility model. Any person skilled in the art can make some changes or modifications within the scope of the technical solution of the present utility model by using the above-disclosed technical content, which is an equivalent embodiment of equivalent changes. However, as long as it does not depart from the content of the technical solution of the present utility model, any simple modification, equivalent change, and modification made to the above embodiment according to the technical essence of the present utility model still fall within the protection scope of the technical solution of the present utility model.

Claims

1. A bare cell prefabricated structure, characterized in that: The invention comprises a prefabricated unit (1), wherein the prefabricated unit (1) has a first length direction (L1), a first width direction (W1) and a first thickness direction (D1) which are perpendicular to each other; the prefabricated unit (1) comprises a positive electrode strip (11), a separator strip (13) and a negative electrode strip (12) which are sequentially stacked in the first thickness direction (D1), wherein the separator strip (13) is stacked on both sides of the positive electrode strip (11) or the negative electrode strip (12); in the first length direction (L1), the positive electrode strip (11) comprises positive electrode ear regions (113) which are arranged at intervals, and the negative electrode strip (12) comprises positive electrode ear regions (113) which are arranged at intervals. It comprises negative electrode ear areas (123) arranged at intervals; in the first thickness direction (D1), the positive electrode strip (11) comprises a positive electrode notch (114) corresponding to the negative electrode ear area (123), and the negative electrode strip (12) comprises a negative electrode notch (124) corresponding to the positive electrode ear area (113); the positive electrode ear area (113) and the negative electrode ear area (123) are arranged at intervals in the first length direction (L1) or the first width direction (W1), and the diaphragm strip (13) is provided with diaphragm notches (131) corresponding one to one to the positive electrode ear area (113) and the negative electrode ear area (123).

2. The bare cell prefabricated structure according to claim 1, characterized in that: The positive electrode ear area (113) and the positive electrode notch (114) are alternately arranged in the first length direction (L1); in the first length direction (L1), the size of the positive electrode ear area (113) is a1, the size of the adjacent negative electrode ear area (123) is b1, the spacing between the positive electrode ear area (113) and the adjacent negative electrode ear area (123) is c1, and the size of the diaphragm belt (13) in the first width direction (W1) is d1; 0.5a1+0.5b1+c1≥d1.

3. The bare cell prefabricated structure according to claim 1, characterized in that: The positive electrode ear area (113) and the positive electrode notch (114) are arranged side by side in the first width direction (W1); in the first length direction (L1), the sizes of the two adjacent positive electrode ear areas (113) are a2 and a3 respectively, and the corresponding sizes of the two adjacent negative electrode ear areas (123) are b2 and b3, the distance between the two adjacent positive electrode ear areas (113) is c2, and the distance between the two adjacent negative electrode ear areas (123) is c3; 0.5a2+c2+0.5a3=0.5b2+c3+0.5b3.

4. The bare cell prefabricated structure according to claim 1, characterized in that: In the first thickness direction (D1), in the negative electrode notch (124) and the diaphragm notch (131) corresponding to the positive electrode ear region (113), the edge of the negative electrode notch (124) overlaps with the edge of the diaphragm notch (131) or is covered by the diaphragm tape (13); in the first thickness direction (D1), in the positive electrode notch (114) and the diaphragm notch (131) corresponding to the negative electrode ear region (123), the edge of the positive electrode notch (114) overlaps with the edge of the diaphragm notch (131) or is covered by the diaphragm tape (13).

5. The bare cell prefabricated structure according to claim 1, characterized in that: The prefabricated unit (1) comprises a winding starting point and a winding end point at both ends of the first length direction (L1), and the spacing between adjacent diaphragm notches (131) in the first length direction (L1) gradually increases from the winding starting point to the winding end point.

6. The bare cell prefabricated structure according to claim 1, characterized in that: The positive electrode ear area (113) and the positive electrode notch (114) are arranged side by side in the first width direction (W1); in the first length direction (L1), the sizes of two adjacent positive electrode ear areas (113) are a2 and a3 respectively, and the distance between two adjacent positive electrode ear areas (113) is c2. The size of the diaphragm belt (13) in the first width direction (W1) is d2, 0.5a2+c2+0.5a3≥d2 or 0.5a2+c2+0.5a3≥2d2.

7. The bare cell prefabricated structure according to claim 6, characterized in that: 0.5a2+c2+0.5a3≥2d2; in the first length direction (L1), the positive electrode strip (11) comprises staggered positive electrode coating areas (111) and positive electrode hollow foil areas (112), the positive electrode ear areas (113) and the positive electrode notch (114) are both located in the positive electrode hollow foil areas (112), and the negative electrode strip (12) comprises staggered negative electrode coating areas (121) and a negative electrode empty foil area (122), the negative electrode ear area (123) and the negative electrode notch (124) are both located in the negative electrode empty foil area (122); the positive electrode strip (11) is further provided with the positive electrode empty foil area (112) between two adjacent positive electrode ear areas (113), and the negative electrode strip (12) is further provided with the negative electrode empty foil area (122) between two adjacent negative electrode ear areas (123).

8. The bare cell prefabricated structure according to any one of claims 1 to 6, characterized in that: In the first length direction (L1), the positive electrode strip (11) comprises staggered positive electrode coating areas (111) and positive electrode empty foil areas (112), the positive electrode ear areas (113) and the positive electrode notch (114) are both located in the positive electrode empty foil areas (112), and the negative electrode strip (12) comprises staggered negative electrode coating areas (121) and negative electrode empty foil areas (122), the negative electrode ear areas (123) and the negative electrode notch (124) are both located in the negative electrode empty foil areas (122).

9. The bare cell prefabricated structure according to claim 8, characterized in that: In the first length direction (L1), each of the positive electrode coating regions (111) has the same length, and each of the negative electrode coating regions (121) has the same length.

10. A bare battery cell, characterized in that: The bare battery cell prefabricated structure is wound according to any one of claims 1 to 9, the winding direction is perpendicular to the winding axis direction, the winding axis direction is parallel to the first width direction (W1), the positive electrode ear area (113), the positive electrode notch (114), the negative electrode ear area (123), the negative electrode notch (124) and the diaphragm notch (131) are all located at the turning point (4) of the bare battery cell (100).

11. The bare battery cell according to claim 10, characterized in that: The size of the bare battery cell (100) in the first length direction (L1) is greater than the size of the bare battery cell in the first width direction (W1).

12. A battery, characterized in that: It comprises a cover plate, a shell and a bare battery cell (100) as described in any one of claims 10 to 11, wherein the long side of the shell is parallel to the first length direction (L1), the cover plate is arranged at the end of the shell along the first length direction (L1), the bare battery cell (100) is located in the shell, and a positive conductive terminal and a negative conductive terminal are provided on the cover plate, the bare battery cell (100) is electrically connected to the positive conductive terminal through the positive electrode ear area (113), and the bare battery cell (100) is electrically connected to the negative conductive terminal through the negative electrode ear area (123).

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