Stacked core and novel battery

Abstract

The utility model relates to the technical field of energy storage, in particular to a stacked core and a novel battery, which comprise a plurality of stacked pole pieces and diaphragms arranged between the adjacent pole pieces, the pole piece comprises a current collector, an active material layer, an insulating layer and a conductive foil layer arranged on the current collector; and in the first direction, the thickness of the conductive foil layer of the first end pole piece in the pole pieces is greater than that of the conductive foil layer of the second end pole piece. According to the invention, the conductive foil layers of the pole pieces at the two ends of the first direction are set to be conductive foil layers with different thicknesses, and in the compaction and combination process, it is only required to ensure that the pole piece with a large deformation quantity is a thicker first end pole piece and the pole piece with a small deformation quantity is a second end pole piece; therefore, low resistance and low thickness of the battery can be ensured on the basis that the conductive foil layer is ensured to be better in welding strength, more difficult to break and higher in yield, and miniaturization, lightening and thinning of the battery cannot be hindered.

Description

Technical Field

[0001] The utility model relates to the technical field of energy storage, in particular to a stacked core and a novel battery. Background Art

[0002] In order to improve the nail penetration performance and impact resistance of battery cells, technicians in the lithium battery industry began to try to convert the current collector from metal foil to a composite current collector, which includes a support layer (insulating layer) and a conductive coating (metal layer) located on the upper and lower sides of the support layer.

[0003] In practical applications, because the upper and lower metal layers of a composite current collector cannot be directly connected, a conductive foil layer is usually welded to each of the upper and lower metal layers of the composite current collector to form a soft tab, and the upper and lower layers are connected through the welded tab. However, this structure easily causes the tab area after welding to be thicker than the tab area of ​​a conventional current collector, resulting in poor welding stability and a longer overall weld area, which is not conducive to the miniaturization and thinness of the battery. It also brings difficulties to the bending and transfer welding of the tab of the battery cell to a certain extent, reducing the yield rate of the finished product in battery production.

[0004] Therefore, how to solve the problem in the prior art that the tabs of the battery stack are too thick, which is not conducive to battery miniaturization and lightweighting, while also taking into account a high finished product yield, is an urgent problem to be solved by those skilled in the art. Utility Model Content

[0005] The purpose of the utility model is to provide a stacked core and a new type of battery to solve the problem in the prior art that it is impossible to take into account the miniaturization, lightness and high yield of the battery.

[0006] In order to solve the above technical problems, the present invention provides a stacked core, comprising a plurality of stacked pole pieces and a diaphragm arranged between adjacent pole pieces;

[0007] The pole piece includes a current collector, an active material layer, an insulating layer and a conductive foil layer arranged on the current collector;

[0008] The current collector includes a polymer layer, a first conductive layer and a second conductive layer, and along a first direction, the first conductive layer and the second conductive layer are respectively arranged on two surfaces of the polymer layer;

[0009] Along the second direction, the first conductive layer and / or the second conductive layer includes a first coating area, a second coating area and a blank area;

[0010] The conductive foil layer includes a connecting portion and an extending portion connected to the connecting portion;

[0011] The active material layer is provided in the first coating area, the connecting portion is fixedly connected to the blank area, and the insulating layer is provided in the second coating area, and the insulating layer isolates the active material layer from the conductive foil layer;

[0012] Along the first direction, the thickness of the conductive foil layer of the first end electrode piece among the electrode pieces is greater than the thickness of the conductive foil layer of the second end electrode piece.

[0013] Optionally, in the stacked core, the pole piece includes a third pole piece, and along the first direction, the third pole piece is located between the first end pole piece and the second end pole piece;

[0014] Along the first direction, the third pole piece includes a first surface and a second surface opposite to each other; wherein the first surface is closer to the first end pole piece than the second surface;

[0015] The conductive foil layer is provided on both the first surface and the second surface; the thickness of the conductive foil layer on the first surface is greater than the thickness of the conductive foil layer on the second surface.

[0016] Optionally, in the stacked core, the thickness of the conductive foil layer of the third electrode piece is between the thickness of the conductive foil layer of the second end electrode piece and the thickness of the conductive foil layer of the first end electrode piece.

[0017] Optionally, in the stacked core, a thickness difference between the conductive foil layer of the first end electrode piece and the conductive foil layer of the second end electrode piece is 2 microns to 10 microns;

[0018] and / or,

[0019] The thickness of the conductive foil layer of the first terminal piece is in a range of 4 microns to 20 microns;

[0020] and / or,

[0021] The thickness of the conductive foil layer of the second terminal piece is in a range of 4 microns to 20 microns;

[0022] and / or,

[0023] The thickness of the conductive foil layer of the third pole piece ranges from 2 microns to 20 microns;

[0024] and / or,

[0025] The thickness of the current collector ranges from 2 micrometers to 20 micrometers.

[0026] Optionally, in the stacked core, the stacked core includes a stacked core body, and the extension portion includes a bent section;

[0027] Along the first direction, the height L of the bending section and the thickness D of the stacked core body satisfy: L=K1*D, where K1 is a proportional coefficient, K1≤1;

[0028] The range of K1 is 0.5-1.

[0029] Optionally, in the stacked core, the stacked core includes a first tab, at least a portion of the extension portion and at least a portion of the first tab overlap and are welded to form a welding area, and along the second direction, a starting welding position of the welding area exceeds the blank area.

[0030] Optionally, in the stacked core, the distance H between the starting welding position of the welding zone and the stacked core body and the thickness D of the stacked core body satisfy: H=K1*K2*D, where K2 is the number of bending times of the conductive foil layer, K2≥1, and K2 is an integer.

[0031] Optionally, in the stacked core, along the first direction, the weld width W of the welding area and the height L of the bending section satisfy: W<L;

[0032] And / or, along the first direction, the weld width W of the welding area and the thickness D of the stacked core body satisfy: W<k1*D.

[0033] Optionally, in the stacked core, the extension portion includes at least three bending segments.

[0034] A novel battery comprises any one of the stacked cores described above.

[0035] The stacked core provided by the present invention comprises a plurality of stacked pole pieces and a diaphragm arranged between adjacent pole pieces; the pole piece comprises a current collector, an active material layer, an insulating layer and a conductive foil layer arranged on the current collector; the current collector comprises a polymer layer, a first conductive layer and a second conductive layer, and along a first direction, the first conductive layer and the second conductive layer are respectively arranged on two surfaces of the polymer layer; along a second direction, the first conductive layer and / or the second conductive layer comprises a first coating area, a second coating area and a blank area; the conductive foil layer comprises a connecting portion and an extension portion connected to the connecting portion; the active material layer is arranged in the first coating area, the connecting portion is fixedly connected to the blank area, the insulating layer is arranged in the second coating area, and the insulating layer isolates the active material layer from the conductive foil layer; along the first direction, the thickness of the conductive foil layer of the first end pole piece in the pole piece is greater than the thickness of the conductive foil layer of the second end pole piece.

[0036] After the stacking of the core bodies is completed, the conductive structures extending from the core bodies need to be compacted and merged. Since the conductive foil layers corresponding to different pole pieces are located at different positions in the thickness of the core bodies, the deformation of the extensions of the conductive foil layers is different during the compaction and consolidation process. In the present invention, the conductive foil layers of the pole pieces at both ends of the first direction are set to conductive foil layers with different thicknesses. During the compaction and merging process, it is only necessary to ensure that the pole piece with the larger deformation is the thicker first end pole piece, and the pole piece with the smaller deformation is the second end pole piece. This ensures better welding strength of the conductive foil layer, is less likely to break, and has a higher yield rate, while ensuring low resistance and low thickness of the battery, and will not hinder the miniaturization and thinness of the battery. The utility model also provides a new battery with the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 A schematic diagram of the partial structure of a specific embodiment of the stacked core provided by the present invention;

[0039] Figure 2 A schematic diagram of the partial structure of a specific embodiment of the stacked core provided by the present invention;

[0040] Figure 3 A schematic diagram of the partial structure of a specific embodiment of the stacked core provided by the present invention;

[0041] Figure 4 A schematic diagram of the partial structure of a specific embodiment of the stacked core provided by the present invention;

[0042] Figure 5 A schematic diagram of the partial structure of a specific embodiment of the stacked core provided by the present invention;

[0043] Figure 6 A schematic structural diagram of a specific embodiment of the stacked core provided by the present invention;

[0044] Figure 7 A structural schematic diagram of another specific embodiment of the stacked core provided by the present invention;

[0045] Figure 8 A schematic diagram showing the dimensions of a specific embodiment of the stacked core provided by the present invention;

[0046] Figure 9 A schematic diagram of dimension markings for a specific embodiment of the stacked core provided by the present invention.

[0047] In the figure, including 100A-first end electrode, 100B-second end electrode, 100C-third electrode, 110-current collector, 120-active material layer, 130-insulating layer, 140-conductive foil layer, 141-connecting part, 142-extension part, 142A-bending section, 150-conductive welding part, 111-polymer layer, 112-first conductive layer, 113-second conductive layer, 01-first coating area, 02-second coating area, 03-blank area, 310-welding area, 311-starting welding position, 320-ear glue. DETAILED DESCRIPTION

[0048] To help those skilled in the art better understand the present invention, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Obviously, the embodiments described are only a portion of the present invention, not all of the embodiments. All other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0049] The core of the present invention is to provide a stacked core, a structural diagram of a specific embodiment of which is shown in FIG. Figures 1 to 2 As shown, it is referred to as specific embodiment 1, including a plurality of stacked pole pieces and a diaphragm arranged between adjacent pole pieces;

[0050] The electrode comprises a current collector 110, an active material layer 120, an insulating layer 130 and a conductive foil layer 140 disposed on the current collector 110;

[0051] The current collector 110 includes a polymer layer 111, a first conductive layer 112, and a second conductive layer 113. Along a first direction, the first conductive layer 112 and the second conductive layer 113 are respectively disposed on two surfaces of the polymer layer 111.

[0052] Along the second direction, the first conductive layer 112 and / or the second conductive layer 113 includes a first coating area 01, a second coating area 02 and a blank area 03;

[0053] The conductive foil layer 140 includes a connecting portion 141 and an extending portion 142 connected to the connecting portion 141;

[0054] The active material layer 120 is disposed in the first coating area 01 , the connecting portion 141 is fixedly connected to the blank area 03 , and the insulating layer 130 is disposed in the second coating area 02 . The insulating layer 130 isolates the active material layer 120 from the conductive foil layer 140 .

[0055] Along the first direction, the thickness of the conductive foil layer 140 of the first end electrode piece 100A among the electrode pieces is greater than the thickness of the conductive foil layer 140 of the second end electrode piece 100B.

[0056] The first direction is the thickness direction of the stacked core, that is, the stacking direction of the pole pieces, or the thickness direction of the current collector 110; the second direction is the length direction of the battery cell, that is, the length direction of the pole pieces, which is perpendicular to the first direction.

[0057] Please see Figure 1 , Figure 1 is a schematic structural diagram of the current collector 110. It should be noted that: Figure 1 The first conductive layer 112 and the second conductive layer 113 can be interchanged, and it is not necessary that the first conductive layer 112 is above the second conductive layer 113. Figure 1 The locations of the first coating area 01, the second coating area 02 and the blank area 03 are also marked, and a schematic diagram of the first direction and the second direction is given.

[0058] The present invention does not limit the positive and negative properties of the electrode. In addition, since the first end electrode 100A and the second end electrode 100B are the electrode pieces at the two ends of the stacked core, the first end electrode 100A and the second end electrode 100B can be electrode pieces with the conductive foil layer 140 set on only one side, and the conductive foil is not set on the surface facing the outside of the stacked core. This can reduce the overall thickness of the stacked core while meeting the conductive needs. Assuming that the first end electrode 100A is the electrode set at the top of the stacked core, and the second end electrode 100B is the electrode set at the bottom of the stacked core, the first end electrode 100A can only have the conductive foil layer 140 set on the lower surface, and the second end electrode 100B can correspondingly only have the conductive foil layer 140 set on the upper surface (correspondingly, the subsequent compaction and merging process of the conductive structure can be compaction and merging from the first end electrode 100A to the second end electrode 100B along the first direction). Please refer to Figure 2 , Figure 2This is a schematic structural diagram of the first terminal plate 100A or the second terminal plate 100B. In the figure, the area where the active material layer 120 is provided corresponds to the first coating area 01, the area where the insulating layer 130 is provided corresponds to the second coating area 02, and the portion where the conductive foil layer 140 is in contact with the current collector 110 is the connecting portion 141, and the corresponding area is the blank area 03. It should be noted that Figure 2 This is only a schematic diagram, so the ratio of the connecting portion 141 and the extending portion 142 in the figure may be different from the actual ratio. In addition, in order to electrically connect the first conductive layer 112 and the second conductive layer 113 located on both sides of the polymer layer 111, the conductive foil layer 140 is usually connected to the first and / or second conductive layer by roller welding. The structure connecting the two conductive layers is the conductive welding portion 150. Figure 3 The conductive foil layer 140 and the conductive welding portion 150 corresponding to the conductive layer are marked with a grid area.

[0059] It can be assumed that the stacked core includes n layers of electrodes in total, and the thickness of the conductive foil layer 140 of the first end electrode 100A can be expressed as X1, and the thickness of the conductive foil layer 140 of the second end electrode 100B can be expressed as X n From the description of this specific embodiment, it can be seen that X1>X n .

[0060] As a preferred embodiment, along the first direction, the third pole piece 100C is located between the first end pole piece 100A and the second end pole piece 100B;

[0061] Along the first direction, the third pole piece 100C includes a first surface and a second surface opposite to each other; wherein the first surface is closer to the first end pole piece 100A than the second surface;

[0062] The conductive foil layer 140 is provided on both the first surface and the second surface; the thickness of the conductive foil layer 140 on the first surface is greater than the thickness of the conductive foil layer 140 on the second surface.

[0063] That is, in this preferred embodiment, the pole pieces in the stacked core are divided into three categories: the first end pole piece 100A, the second end pole piece 100B located at both ends of the stacked core, and the third pole piece 100C not at the end of the stacked core. Figure 4, corresponding conductive foil layers 140 are provided on both sides of the third electrode piece 100C. Since the deformation of the conductive foil layer 140 of the first end electrode piece 100A is greater than the deformation of the second end electrode piece 100B during the subsequent compaction and merging process, the deformation of the conductive foil layer 140 on the first surface closer to the first end electrode piece 100A will definitely be greater than the conductive foil layer 140 on the second surface relatively far away from the first end electrode piece 100A. Therefore, setting the thickness of the conductive foil layer 140 on the first surface to be greater than the thickness of the conductive foil layer 140 on the second surface can achieve better welding strength, making the conductive foil layer 140 less likely to break, and improving the yield rate of finished products. In addition, the third electrode piece 100C still requires the conductive welding portion 150 to electrically connect the conductive layers on the two surfaces. The structural schematic diagram of the third electrode piece 100C electrically connecting the two conductive layers through the conductive welding portion 150 is shown in Figure 5 .

[0064] The thickness of the conductive foil layer 140 on the first surface of the third electrode 100C can be expressed as X a1 The thickness of the conductive foil layer 140 on the second surface of the third electrode 100C is represented as X a2 , then through the above expression we can get, X a1 >X a2 .

[0065] Furthermore, the thickness of the conductive foil layer 140 of the third electrode piece is between the thickness of the conductive foil layer 140 of the second end electrode piece 100B and the thickness of the conductive foil layer 140 of the first end electrode piece 100A. In this preferred embodiment, it is provided that X n <X a2 <X a1 <X1, by limiting the thickness of the conductive foil layer 140 of the third electrode 100C to between the thickness of the conductive foil layer 140 of the second end electrode 100B and the thickness of the conductive foil layer 140 of the first end electrode 100A, the thickness relationship of the conductive foil layer 140 is optimized, the risk of the entire conductive foil layer 140 falling off during the lower compaction and merging process is reduced, the welding strength is increased, the structure is optimized, and the resistance of the conductive welding portion 150 is reduced.

[0066] For easier understanding, please refer to Figure 6 and Figure 7 , Figure 6 Figure 7 The overall structure of the stacked core is shown.

[0067] Preferably, the difference in thickness between the conductive foil layer 140 of the first end electrode 100A and the conductive foil layer 140 of the second end electrode 100B is 2 μm to 10 μm, such as any one of 2.0 μm, 5.6 μm or 10.0 μm; the thickness range of the conductive foil layer 140 of the first end electrode 100A is 4 μm to 20 μm, such as any one of 4.0 μm, 14.1 μm or 20.0 μm; the thickness range of the conductive foil layer 140 of the second end electrode 100B is 4 μm to 20 μm, such as any one of 4.0 μm, 10.1 μm or 20.0 μm; the thickness range of the conductive foil layer 140 of the third electrode 100C is 2 μm to 20 μm, such as any one of 2.0 μm, 8.8 μm or 20.0 μm; the thickness range of the current collector 110 is 2 μm to 20 μm, such as any one of 2.0 μm, 19.9 μm or 20.0 μm. The above ranges are preferred values ​​based on extensive theoretical calculations and practical tests. Of course, other parameters may be used based on actual conditions, and the present invention is not limited thereto. The conductive foil layer 140 may be a metal foil layer, such as copper foil, aluminum foil, etc., or a conductive layer of other materials, and the present invention is not limited thereto.

[0068] The conductive foil layer 140 of the third electrode 100C also requires welding. During the welding process, the upper conductive foil layer 140 contacts the upper welding head, and the lower conductive foil layer 140 contacts the bottom welding seat. In the actual process, it was found that when both conductive foil layers 140 use thick foil materials, welding is normal; when both use ultra-thin foil materials with the same thickness, it is very easy for the lower conductive foil layer 140 that contacts the welding seat to adhere to the bottom welding seat, while the upper conductive foil layer 140 does not. This problem greatly affects the yield and efficiency of the process. It has been verified that adjusting the thickness relationship between the upper conductive foil 0 and the lower conductive foil layer 140 can circumvent this problem. That is, the upper conductive foil layer 140 can use ultra-thin foil materials, and the lower conductive foil layer 140 can use thin foil materials, so that the thickness of the upper conductive foil layer 140 is less than that of the lower conductive foil layer 140.

[0069] The thickness difference between the upper conductive foil layer 140 and the lower conductive foil layer 140 ranges from 2 microns to 10 microns, including endpoint values, such as any one of 2.0 microns, 5.5 microns or 10.0 microns; a smaller thickness difference will result in almost no difference in welding effect, while a larger difference will make it difficult to control welding parameters. The appropriate thickness difference within the above range can not only avoid the risk of the lower foil material adhering to the weld seat, but also facilitate the control of welding parameters and stabilize the process.

[0070] The stacked core provided by the present invention comprises a plurality of stacked pole pieces and a diaphragm arranged between adjacent pole pieces; the pole piece comprises a current collector 110, an active material layer 120, an insulating layer 130 and a conductive foil layer 140 arranged on the current collector 110; the current collector 110 comprises a polymer layer 111, a first conductive layer 112 and a second conductive layer 113, and along a first direction, the first conductive layer 112 and the second conductive layer 113 are respectively arranged on two surfaces of the polymer layer 111; along a second direction, the first conductive layer 112 and / or the second conductive layer 113 include a first coating area 01, a second coating area 02 and a blank area 03; the conductive foil layer 140 includes a connecting portion 141 and an extending portion 142 connected to the connecting portion 141; the active material layer 120 is arranged in the first coating area 01, the connecting portion 141 is fixedly connected to the blank area 03, and the insulating layer 130 is arranged in the second coating area 02, and the insulating layer 130 isolates the active material layer 120 from the conductive foil layer 140; along the first direction, the thickness of the conductive foil layer 140 of the first end electrode 100A in the electrode is greater than the thickness of the conductive foil layer 140 of the second end electrode 100B. After the stacking of the core body is completed, the conductive structure extending from the core body needs to be compacted and merged. Since the conductive foil layers 140 corresponding to different pole pieces are located at different positions in the thickness of the core body, the deformation of the extension portion 142 of each conductive foil layer 140 is different during the compaction and compaction process. In the present invention, the conductive foil layers 140 of the pole pieces located at both ends of the first direction are set to conductive foil layers 140 with different thicknesses. During the compaction and merging process, it is only necessary to ensure that the pole piece with a larger deformation is the thicker first end pole piece 100A, and the pole piece with a smaller deformation is the second end pole piece 100B. This can ensure better welding strength of the conductive foil layer 140 and make it less prone to breakage, that is, higher yield, while ensuring low resistance and low thickness of the battery, and will not hinder the miniaturization and thinness of the battery.

[0071] On the basis of the specific embodiment 1, the extension portion 142 of the conductive foil layer 140 is further defined to obtain the specific embodiment 2, and the corresponding structural diagram thereof is shown as follows: Figure 6 and Figure 7 As shown, it is referred to as the second embodiment, comprising a plurality of stacked pole pieces and a diaphragm disposed between adjacent pole pieces;

[0072] The electrode comprises a current collector 110, an active material layer 120, an insulating layer 130 and a conductive foil layer 140 disposed on the current collector 110;

[0073] The current collector 110 includes a polymer layer 111, a first conductive layer 112, and a second conductive layer 113. Along a first direction, the first conductive layer 112 and the second conductive layer 113 are respectively disposed on two surfaces of the polymer layer 111.

[0074] Along the second direction, the first conductive layer 112 and / or the second conductive layer 113 includes a first coating area 01, a second coating area 02 and a blank area 03;

[0075] The conductive foil layer 140 includes a connecting portion 141 and an extending portion 142 connected to the connecting portion 141;

[0076] The active material layer 120 is disposed in the first coating area 01 , the connecting portion 141 is fixedly connected to the blank area 03 , and the insulating layer 130 is disposed in the second coating area 02 . The insulating layer 130 isolates the active material layer 120 from the conductive foil layer 140 .

[0077] Along the first direction, the thickness of the conductive foil layer 140 of the first end electrode piece 100A among the electrode pieces is greater than the thickness of the conductive foil layer 140 of the second end electrode piece 100B;

[0078] The stacked core includes a stacked core body, and the extension portion 142 includes a bent section 142A;

[0079] Along the first direction, the height L of the bending section 142A and the thickness D of the stacked core body satisfy: L=K1*D, where K1 is a proportional coefficient, K1≤1;

[0080] The range of K1 is 0.5-1.

[0081] The difference between this embodiment and the above embodiment is that this embodiment further specifies the extension arrangement of the extension portion 142 , and the remaining structures are the same as those in the above embodiment, which will not be described in detail here.

[0082] The stacked core body in this specific embodiment refers to a structure formed by stacking all the pole pieces and all the diaphragms excluding the extension portion 142, and the height L of the bending section 142A refers to the length of the bending section 142A in the first direction, and the thickness D of the stacked core body refers to the thickness of the stacked core body in the first direction.

[0083] Please refer to Figure 6 and Figure 7In this specific embodiment, the portion of the conductive foil layer 140 extending from the stacked core body is bent to form a plurality of bent segments 142A. The plurality of bent segments 142A extend back and forth in the first direction, thereby greatly reducing the space occupied by the extension portion 142, thereby facilitating the miniaturization and lightweighting of the battery stacked core. It should be noted that the extension portion of the conductive foil layer 140 is folded once to form two bent segments. Of course, Figure 6 and Figure 7 The positions of the first end electrode 100A and the second end electrode 100B can be interchanged, and the present invention does not limit this.

[0084] As a specific embodiment, the stacked core includes a first tab, at least part of the extension portion 142 and at least part of the first tab overlap and are welded to form a welding area 310 , and along the second direction, a starting welding position 311 of the welding area 310 exceeds the blank area 03 .

[0085] The stacked core is directly connected to the external circuit through the first pole ear to complete electrical transmission. In the present embodiment, the first pole ear is overlapped with at least a portion of the extension portion 142 for welding, which greatly improves the reliability of welding. At the same time, the welding area 310 is limited to not be located in the blank area 03, thereby avoiding the rigid welding area 310 from limiting the mobility of the extension portion 142. Compared with other settings of the welding area 310, the flexibility of the extension portion 142 is improved, so that the stacked core can adapt to more setting spaces, improves versatility, and at the same time avoids the extension portion 142 from breaking, thereby improving the working stability of the stacked core. Figure 6 and Figure 7 The tab glue 320 for fixing the first tab is also marked.

[0086] Furthermore, the distance H between the starting welding position 311 of the welding area 310 and the laminated core body and the thickness D of the laminated core body satisfy: H=K1*K2*D, where K2 is the number of bending times of the conductive foil layer 140, K2≥1, and K2 is an integer.

[0087] As shown above, the height L of the bending section 142A is K1*D, so the distance H between the starting welding position 311 of the welding area 310 and the stacked core body can also be expressed as H=L*K2. In this way, by designing the transfer welding starting point at the starting position of the (k2+1) fold, it is avoided that the starting position of the weld point is on the k2 and previous bending circles, and the tail of the weld mark is on the k2+1 bending circle, that is, the weld mark of the transfer weld is avoided from being bent, the transfer weld weld mark structure is protected, and the tab is prevented from falling off and being damaged.

[0088] Furthermore, along the first direction, the weld width W of the welding area 310 and the height L of the bending section 142A satisfy: W<L;

[0089] And / or, along the first direction, the weld width W of the welding area 310 and the thickness D of the stacked core body satisfy: W<k1*D.

[0090] In this preferred embodiment, the weld width W of the welding area 310 is limited. The weld width W refers to the length of the welding area 310 on the extension portion 142. In this preferred embodiment, the weld width W is limited to less than the height L of the bending section, that is, one bending section can accommodate the welding area 310, and the welding area 310 will not bend between the two extension portions 142, thereby greatly reducing the process difficulty and the problem of unstable connection caused by the bending welding area, and improving production efficiency and yield. Regarding the thickness D of the stacked core body, the height L of the bending section 142A, the weld width W and the distance H between the starting welding position 311 and the stacked core body, you can refer to Figure 8 and Figure 9 ,in, Figure 8 and Figure 7 Corresponding, Figure 9 This is a structural diagram of the extension portion 142 after being compacted and merged but not yet bent to form the bent section 142A. It should be noted that one end of the distance H is the starting welding position 311 of the welding area 310, and the other end is the compacted and merged position of the extension portion 142.

[0091] In one embodiment, the extension portion 142 includes at least three bent segments 142A. This embodiment employs multiple bends to ensure that the height L of the bent segments 142A does not exceed the thickness D of the stacked core body, thereby meeting the thickness requirements of the ultra-thin stacked core. In this embodiment, the bent segments 142A are arranged in an N-shaped or M-shaped pattern, or a combination of N and M. In other words, the bend points of all the bent segments 142A in this embodiment are positioned at the same height. This arrangement of the conductive foil layer 140 further enhances the compactness of the stacking of the bent segments 142A, reduces design and production complexity, and improves the yield rate of the finished product.

[0092] The present invention also provides a new type of battery, which includes a stacked core as described in any one of the above. The stacked core provided by the present invention includes a plurality of stacked pole pieces and a separator arranged between adjacent pole pieces; the pole piece includes a current collector 110, an active material layer 120, an insulating layer 130 and a conductive foil layer 140 arranged on the current collector 110; the current collector 110 includes a polymer layer 111, a first conductive layer 112 and a second conductive layer 113, and along the first direction, the first conductive layer 112 and the second conductive layer 113 are respectively arranged on the two surfaces of the polymer layer 111; along the second direction, the first conductive layer 112 and / or the second conductive layer 113 include a first coating area 01, a second coating area 02 and a blank area 03; the conductive foil layer 140 includes a connecting portion 141 and an extending portion 142 connected to the connecting portion 141; the active material layer 120 is arranged in the first coating area 01, the connecting portion 141 is fixedly connected to the blank area 03, and the insulating layer 130 is arranged in the second coating area 02, and the insulating layer 130 isolates the active material layer 120 from the conductive foil layer 140; along the first direction, the thickness of the conductive foil layer 140 of the first end electrode 100A in the electrode is greater than the thickness of the conductive foil layer 140 of the second end electrode 100B. After the stacking of the core body is completed, the conductive structure extending from the core body needs to be compacted and merged. Since the conductive foil layers 140 corresponding to different pole pieces are located at different positions in the thickness of the core body, the deformation of the extension portion 142 of each conductive foil layer 140 is different during the compaction and compaction process. In the present invention, the conductive foil layers 140 of the pole pieces located at both ends of the first direction are set to conductive foil layers 140 with different thicknesses. During the compaction and merging process, it is only necessary to ensure that the pole piece with a larger deformation is the thicker first end pole piece 100A, and the pole piece with a smaller deformation is the second end pole piece 100B. This can ensure better welding strength of the conductive foil layer 140 and make it less prone to breakage, that is, higher yield, while ensuring low resistance and low thickness of the battery, and will not hinder the miniaturization and thinness of the battery.

[0093] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. Reference can be made to the descriptions of the identical or similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and the relevant parts can be referred to the descriptions of the methods.

[0094] It should be noted that, in this specification, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" 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 includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0095] The above describes in detail the stacked core and novel battery provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above examples is intended only to facilitate understanding of the method and core concept of the present invention. It should be noted that those skilled in the art may make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications fall within the scope of protection of the claims of the present invention.

Claims

1. A stacked core, characterized in that: It includes a plurality of stacked pole pieces and a diaphragm arranged between adjacent pole pieces; The pole piece includes a current collector, an active material layer, an insulating layer and a conductive foil layer arranged on the current collector; The current collector includes a polymer layer, a first conductive layer and a second conductive layer, and along a first direction, the first conductive layer and the second conductive layer are respectively arranged on two surfaces of the polymer layer; Along the second direction, the first conductive layer and / or the second conductive layer includes a first coating area, a second coating area and a blank area; The conductive foil layer includes a connecting portion and an extending portion connected to the connecting portion; The active material layer is provided in the first coating area, the connecting portion is fixedly connected to the blank area, and the insulating layer is provided in the second coating area, and the insulating layer isolates the active material layer from the conductive foil layer; Along the first direction, the thickness of the conductive foil layer of the first end electrode piece among the electrode pieces is greater than the thickness of the conductive foil layer of the second end electrode piece.

2. The stacked core according to claim 1, wherein: The pole piece includes a third pole piece, and along the first direction, the third pole piece is located between the first end pole piece and the second end pole piece; Along the first direction, the third pole piece includes a first surface and a second surface opposite to each other; wherein the first surface is closer to the first end pole piece than the second surface; The conductive foil layer is provided on both the first surface and the second surface; the thickness of the conductive foil layer on the first surface is greater than the thickness of the conductive foil layer on the second surface.

3. The stacked core according to claim 2, wherein: The thickness of the conductive foil layer of the third pole piece is between the thickness of the conductive foil layer of the second end pole piece and the thickness of the conductive foil layer of the first end pole piece.

4. The stacked core according to claim 2, wherein: The difference in thickness between the conductive foil layer of the first terminal piece and the conductive foil layer of the second terminal piece is 2 microns to 10 microns; and / or, The thickness of the conductive foil layer of the first terminal piece is in a range of 4 microns to 20 microns; and / or, The thickness of the conductive foil layer of the second terminal piece is in a range of 4 microns to 20 microns; and / or, The thickness of the conductive foil layer of the third pole piece ranges from 2 microns to 20 microns; and / or, The thickness of the current collector ranges from 2 micrometers to 20 micrometers.

5. The stacked core according to claim 1, wherein: The stacked core includes a stacked core body, and the extension portion includes a bent section; Along the first direction, the height L of the bending section and the thickness D of the stacked core body satisfy: L=K1*D, where K1 is a proportional coefficient, K1≤1; The range of K1 is 0.5-1.

6. The stacked core according to claim 5, wherein: The stacked core includes a first tab, at least a portion of the extension portion and at least a portion of the first tab overlap and are welded to form a welding area, and along the second direction, a starting welding position of the welding area exceeds the blank area.

7. The stacked core according to claim 6, wherein: The distance H between the starting welding position of the welding zone and the laminated core body and the thickness D of the laminated core body satisfy: H=K1*K2*D, where K2 is the number of bending times of the conductive foil layer, K2≥1, and K2 is an integer.

8. The stacked core according to claim 6, wherein: Along the first direction, the weld width W of the welding area and the height L of the bending section satisfy: W<L; And / or, along the first direction, the weld width W of the welding area and the thickness D of the stacked core body satisfy: W<k1*D.

9. The stacked core according to claim 5, wherein: The extension portion includes at least two bending segments.

10. A new type of battery, characterized in that: The novel battery comprises the stacked core according to any one of claims 1 to 9.

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