Stacked core and battery

Abstract

The utility model provides a laminated core and a battery, and belongs to the technical field of batteries, and the laminated core comprises negative plates and positive plates which are alternately laminated along a first direction. Wherein at least one side of the negative plate close to the positive plate is provided with a first diaphragm layer, and at least one side of the positive plate close to the negative plate is provided with a second diaphragm layer. The adjacent first diaphragm layer and second diaphragm layer are matched with each other so as to limit the relative displacement of the positive plate and the negative plate in the second direction. Wherein the first direction and the second direction intersect with each other. According to the laminated core provided by the embodiment of the invention, the dislocation problem between the positive plate and the negative plate can be reduced, the laminated core quality is improved, the production efficiency is ensured, and the short-circuit risk is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a core and a battery. BACKGROUND

[0002] In the related art, during the preparation of a laminated battery, a movable lamination table is usually used to pull the separator back and forth between the lamination platforms to realize the cross-stacking of the positive and negative electrode sheets, thereby forming a core. During the pulling of the separator, the separator is prone to wrinkling, which affects the production efficiency, and the positive and negative electrode sheets are prone to misalignment during assembly, circulation and welding, thereby affecting the quality of the core and increasing the risk of short circuit. CONTENT OF THE UTILITY MODEL

[0003] Embodiments of the present application provide a core and a battery, which can reduce the misalignment problem between the positive and negative electrode sheets, improve the quality of the core, ensure the production efficiency, and reduce the risk of short circuit.

[0004] In a first aspect, embodiments of the present application provide a core, comprising negative electrode sheets and positive electrode sheets alternately stacked along a first direction;

[0005] Among them, at least one side of the negative electrode sheet close to the positive electrode sheet has a first separator layer, and at least one side of the positive electrode sheet close to the negative electrode sheet has a second separator layer;

[0006] The adjacent first separator layer and second separator layer cooperate with each other to limit the relative displacement of the positive and negative electrode sheets in a second direction;

[0007] Among them, the first direction and the second direction intersect each other.

[0008] In some embodiments, the adjacent first separator layer and second separator layer are bonded to each other to limit the relative displacement of the positive and negative electrode sheets in the second direction.

[0009] In some embodiments, the first separator layer comprises a first polymer frame layer;

[0010] And / or, the second separator layer comprises a second polymer frame layer.

[0011] In some embodiments, the first separator layer has a side close to the second separator layer, and a first groove and a first protrusion are alternately distributed along the second direction;

[0012] And / or, the second separator layer has a side close to the first separator layer, and a second groove and a second protrusion are alternately distributed along the second direction;

[0013] Among them, the second direction and the first direction intersect each other.

[0014] In some embodiments, the first groove and the second groove are one-to-one corresponding, and the first protrusion and the second protrusion are one-to-one corresponding, so that the first groove and the second groove form the wicking channel.

[0015] In some embodiments, the width D1 of the first groove along the second direction is 1mm-2mm, and the width D2 of the first protrusion along the second direction is 1mm-2mm;

[0016] And / or, the width D3 of the second groove along the second direction is 1mm-2mm, and the width D4 of the second protrusion along the second direction is 1mm-2mm.

[0017] In some embodiments, the thickness of the first diaphragm layer along the first direction is 10-15μm;

[0018] And / or, the thickness of the second diaphragm layer along the first direction is 10-15μm.

[0019] In some embodiments, the depth H1 of the first groove along the first direction is 1μm-5μm;

[0020] And / or, the depth H2 of the second groove along the first direction is 1μm-5μm.

[0021] In some embodiments, the negative electrode sheet includes a first negative electrode sheet and a second negative electrode sheet, and the first diaphragm layer includes a first diaphragm sub-layer, a second diaphragm sub-layer and a third diaphragm sub-layer;

[0022] Wherein, the first negative electrode sheet is arranged on the opposite sides of the stack in the first direction, and the second negative electrode sheet is arranged between the adjacent two positive electrode sheets;

[0023] One side of the first negative electrode sheet in the first direction is provided with the first diaphragm sub-layer, and the opposite sides of the second negative electrode sheet in the first direction are respectively provided with the second diaphragm sub-layer and the third diaphragm sub-layer.

[0024] In some embodiments, the first negative electrode sheet includes a ceramic layer, a first negative electrode current collector layer, a first negative electrode material layer, and a first diaphragm sub-layer arranged in the first direction; the ceramic layer and the first negative electrode material layer are respectively arranged on the opposite sides of the first negative electrode current collector layer in the first direction, and the first diaphragm sub-layer is arranged on the side of the first negative electrode material layer away from the first negative electrode current collector layer;

[0025] And / or, the second negative electrode sheet includes a second diaphragm sub-layer, a second negative electrode material layer, a second negative electrode current collector layer, a third negative electrode material layer, and a third diaphragm sub-layer arranged in the first direction; the second negative electrode material layer and the third negative electrode material layer are respectively arranged on the opposite sides of the second negative electrode current collector layer in the first direction, the second diaphragm sub-layer is arranged on the side of the second negative electrode material layer away from the second negative electrode current collector layer, and the third diaphragm sub-layer is arranged on the side of the third negative electrode material layer away from the second negative electrode current collector layer.

[0026] In some embodiments, the ceramic layer has a thickness of 2-5 μm in the first direction.

[0027] In some embodiments, the second diaphragm layer comprises a fourth diaphragm sublayer and a fifth diaphragm sublayer.

[0028] The positive electrode sheet comprises, in the first direction, the fourth diaphragm sublayer, the first positive electrode material layer, the positive electrode current collector layer, the second positive electrode material layer, and the fifth diaphragm sublayer.

[0029] The first positive electrode material layer and the second positive electrode material layer are respectively arranged on opposite sides of the positive electrode current collector layer in the first direction, the fourth diaphragm sublayer is arranged on a side of the first positive electrode material layer away from the positive electrode current collector layer, and the fifth diaphragm sublayer is arranged on a side of the second positive electrode material layer away from the positive electrode current collector layer.

[0030] In a second aspect, the present application also provides a battery comprising the above core stack.

[0031] The present application has the following beneficial effects:

[0032] In the embodiments of the present application, the core stack comprises, in the first direction, positive electrode sheets and negative electrode sheets arranged alternately. At least one side of each negative electrode sheet close to the positive electrode sheet has a first diaphragm layer, and at least one side of each positive electrode sheet close to the negative electrode sheet has a second diaphragm layer. The adjacent first diaphragm layer and second diaphragm layer cooperate with each other to limit the relative displacement of the positive electrode sheet and the negative electrode sheet in the second direction, wherein the first direction and the second direction intersect each other. On the one hand, by arranging the first diaphragm layer on at least one side of the negative electrode sheet close to the positive electrode sheet and the second diaphragm layer on at least one side of the positive electrode sheet close to the negative electrode sheet, the risk of misalignment of the negative electrode sheet, the positive electrode sheet, and the diaphragm is reduced compared with the way of arranging a separate diaphragm between the negative electrode sheet and the positive electrode sheet in the related art. On the other hand, by the cooperation of the adjacent first diaphragm layer and second diaphragm layer, the misalignment of the positive electrode sheet and the negative electrode sheet can be prevented, the probability of misalignment of the core stack during preparation, circulation, etc. is reduced, the risk of short circuit between the positive electrode sheet and the negative electrode sheet is reduced, and the safety performance of the core stack is improved. That is, the core stack provided in the embodiments of the present application can reduce the misalignment problem between the positive electrode sheet and the negative electrode sheet, improve the quality of the core stack, ensure the production efficiency, and reduce the risk of short circuit. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the following embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0034] Figure 1is a cross-sectional structure schematic diagram of the laminated core provided by an embodiment of the present application;

[0035] Figure 2 is a cross-sectional structure schematic diagram of the first negative electrode sheet provided by an embodiment of the present application;

[0036] Figure 3 is a cross-sectional structure schematic diagram of the second negative electrode sheet provided by an embodiment of the present application;

[0037] Figure 4 is a cross-sectional structure schematic diagram of the positive electrode sheet provided by an embodiment of the present application;

[0038] Figure 5 is a top view structure schematic diagram of the positive electrode sheet provided by an embodiment of the present application;

[0039] Figure 6 is a top view structure schematic diagram of the negative electrode sheet provided by an embodiment of the present application;

[0040] Figure 7 is a structure schematic diagram of the positive electrode sheet and the negative electrode sheet after lamination provided by an embodiment of the present application.

[0041] Legend of reference signs:

[0042] 1, negative electrode sheet; 11, first negative electrode sheet; 111, ceramic layer; 112, first negative electrode current collector layer; 113, first negative electrode material layer; 114, negative electrode tab; 12, second negative electrode sheet; 121, second negative electrode material layer; 122, second negative electrode current collector layer; 123, third negative electrode material layer; 2, positive electrode sheet; 21, first positive electrode material layer; 22, positive electrode current collector layer; 23, second positive electrode material layer; 24, positive electrode tab; 3, first separator layer; 31, first separator sub-layer; 311, first groove; 312, first protrusion; 32, second separator sub-layer; 33, third separator sub-layer; 4, second separator layer; 41, fourth separator sub-layer; 411, second groove; 412, second protrusion; 42, fifth separator sub-layer; 5, infiltration channel. DETAILED DESCRIPTION

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0044] Firstly, such as Figure 1 As shown, an embodiment of this application provides a stacked core, including a negative electrode 1 and a positive electrode 2 alternately stacked along a first direction X. The negative electrode 1 has a first separator layer 3 at least on the side closest to the positive electrode 2, and the positive electrode 2 has a second separator layer 4 at least on the side closest to the negative electrode 1. Adjacent first separator layers 3 and second separator layers 4 cooperate to restrict the relative displacement of the positive electrode 2 and the negative electrode 1 in the second direction Y. On the one hand, by providing a first separator layer 3 at least near the positive electrode 2 in the negative electrode 1 and a second separator layer 4 at least near the negative electrode 1 in the positive electrode 2, the risk of misalignment between the negative electrode 1, positive electrode 2, and separator is reduced compared to the related art method of providing a separate separator between the negative electrode 1 and the positive electrode 2. On the other hand, the cooperation between adjacent first separator layers 3 and second separator layers 4 can prevent misalignment between the positive electrode 2 and the negative electrode 1, reducing the probability of misalignment during the preparation and turnover of the stack, reducing the risk of short circuit between the positive electrode 2 and the negative electrode 1, and improving the safety performance of the stack. In other words, the stack provided in this application embodiment can reduce the misalignment problem between the positive electrode 2 and the negative electrode 1, improve the stack quality, ensure production efficiency, and reduce the risk of short circuit.

[0045] It is understood that in the stacked core provided in this application embodiment, the negative electrode 1 and the positive electrode 2 are stacked alternately, that is, stacked in the form of negative electrode 1-positive electrode 2-negative electrode 1-positive electrode 2-negative electrode 1. By replacing the separator in related technologies with the first separator layer 3 in the negative electrode 1 and the second separator layer 4 in the positive electrode 2, it is not necessary to place a separator between the negative electrode 1 and the positive electrode 2 when stacking them, simplifying the manufacturing process and improving production efficiency. Furthermore, by integrating the first separator layer 3 onto the negative electrode 1 and the second separator layer 4 onto the positive electrode 2, the risk of misalignment between the negative electrode 1, the positive electrode 2, and the separator can be reduced.

[0046] The cooperation between the first diaphragm layer 3 and the second diaphragm layer 4 can be realized in various ways. For example, the first diaphragm layer 3 and the second diaphragm layer 4 can be bonded, or the cooperation between the first diaphragm layer 3 and the second diaphragm layer 4 can be realized through other forms of cooperation such as embedding and clamping.

[0047] In some embodiments, the adjacent first diaphragm layer 3 and the second diaphragm layer 4 are bonded to each other to limit the relative displacement of the positive electrode sheet 2 and the negative electrode sheet 1 in the second direction Y.

[0048] That is, by bonding the adjacent first diaphragm layer 3 and the second diaphragm layer 4 to each other, the positive electrode sheet 2 and the negative electrode sheet 1 can be connected to each other to form a whole, so that the positive electrode sheet 2 and the negative electrode sheet are tightly connected, and the misalignment between the positive electrode sheet 2 and the negative electrode sheet 1 is reduced.

[0049] In some embodiments, the first diaphragm layer 3 comprises a first polymer framework layer.

[0050] Specifically, the material of the first polymer framework layer can include a polymer material and a bonding agent. The polymer has good chemical stability and does not react with or dissolve in the electrolyte in the battery. The polymer framework layer made of the polymer has high mechanical strength, which helps to improve the structural strength of the core. The bonding agent can bond the polymer, improve the forming ability, and improve the adhesion of the first polymer framework layer, so that the first polymer framework layer and the second polymer framework layer are bonded to each other.

[0051] For example, the polymer material includes at least one of polyacrylate, polymethyl methacrylate, polyethylene oxide, polypropylene oxide, polyvinylidene fluoride, polyacrylonitrile, polyimide, and polyvinyl alcohol. The bonding agent includes at least one of polyvinylidene fluoride, styrene-butadiene rubber, sodium carboxymethyl cellulose, polyvinyl alcohol, and polyacrylic acid.

[0052] In some embodiments, the second diaphragm layer 4 comprises a second polymer framework layer.

[0053] The second polymer framework layer is basically the same as the first polymer framework layer and has similar technical effects, which will not be described here.

[0054] It can be understood that the material composition of the first polymer framework layer and the second polymer framework layer provided in the embodiments of the present application is only used for exemplary description and does not limit the protection scope of the present application.

[0055] The first polymer framework layer and the second polymer framework layer can be bonded by hot pressing or cold pressing.

[0056] In some embodiments, as Figures 2-4As shown, the first diaphragm layer 3 is provided with first grooves 311 and first protrusions 312 alternately distributed along the second direction Y on the side close to the second diaphragm layer 4; and / or, the second diaphragm layer 4 is provided with second grooves 411 and second protrusions 412 alternately distributed along the second direction Y on the side close to the first diaphragm layer 3. The second direction Y and the first direction X are perpendicular to each other.

[0057] In one embodiment, the first diaphragm layer 3 is provided with first grooves 311 and first protrusions 312 alternately distributed along the second direction Y on the side close to the second diaphragm layer 4; and the second diaphragm layer 4 is provided with second grooves 411 and second protrusions 412 alternately distributed along the second direction Y on the side close to the first diaphragm layer 3.

[0058] In another embodiment, only the first diaphragm layer 3 is provided with first grooves 311 and first protrusions 312 alternately distributed along the second direction Y on the side close to the second diaphragm layer 4.

[0059] In still another embodiment, only the second diaphragm layer 4 is provided with second grooves 411 and second protrusions 412 alternately distributed along the second direction Y on the side close to the first diaphragm layer 3.

[0060] Through the above embodiments, the negative electrode sheet 1 and the positive electrode sheet 2 can be spaced by the first diaphragm layer 3 and the second diaphragm layer 4, and at the same time, a passage can be formed between the negative electrode sheet 1 and the positive electrode sheet 2, so as to improve the absorption efficiency of the electrolyte by the core.

[0061] In some embodiments, as shown, Figure 1 The first grooves 311 and the second grooves 411 correspond to each other, and the first protrusions 312 and the second protrusions 412 correspond to each other, so that the first grooves 311 and the second grooves 411 form the infiltration channel 5. It can be understood that the infiltration channel 5 is located between the adjacent first diaphragm layer 3 and the second diaphragm layer 4, that is, the infiltration channel 5 is located between the adjacent negative electrode sheet 1 and the positive electrode sheet 2.

[0062] That is, when the first diaphragm layer 3 is provided with first grooves 311 and first protrusions 312 alternately distributed along the second direction Y on the side close to the second diaphragm layer 4; and the second diaphragm layer 4 is provided with second grooves 411 and second protrusions 412 alternately distributed along the second direction Y on the side close to the first diaphragm layer 3, the first grooves 311 and the second grooves 411 are correspondingly arranged, and the first protrusions 312 and the second protrusions 412 are correspondingly arranged, so that the first diaphragm layer 3 and the second diaphragm layer 4 form the infiltration channel 5, further improving the absorption efficiency of the electrolyte by the core, and enabling the positive electrode sheet 2 and the negative electrode sheet 1 to be more closely attached.

[0063] The first groove 311 and the second groove 411 can be formed by a laser etching process, for example, the laser power can be 20W-100W.

[0064] In some embodiments, as shown in FIG. 3, the width D1 of the first groove 311 along the second direction Y is 1mm-2mm, and the width D2 of the first protrusion 312 along the second direction Y is 1mm-2mm. Figure 2

[0065] By setting the width D1 of the first groove 311 along the second direction Y to 1mm-2mm, a relatively dense groove structure can be formed on the surface of the first diaphragm layer 3, so that the first groove 311 and the second groove 411 cooperate to form more infiltration channels 5, thereby improving the absorption efficiency of the electrolyte by the stack core. By setting the width D2 of the first protrusion 312 along the second direction Y to 1mm-2mm, the structural strength can be ensured, and at the same time, a larger bonding area can be provided between the first diaphragm layer 3 and the second diaphragm layer 4, thereby ensuring the bonding effect between the first diaphragm layer 3 and the second diaphragm layer 4.

[0066] Similarly, as shown in FIG. 4, the width D3 of the second groove 411 along the second direction Y is also set to 1mm-2mm, and the width D4 of the second protrusion 412 along the second direction Y is also set to 1mm-2mm. Figure 4

[0067] In some embodiments, the thickness of the first diaphragm layer 3 along the first direction X is 10-15μm. By setting the thickness of the first diaphragm layer 3 along the first direction X to 10-15μm, the energy density of the battery can be improved on the basis of ensuring safety. Specifically, if the thickness of the first diaphragm layer 3 is too small, the positive electrode sheet 2 and the negative electrode sheet 1 are easy to cause contact short circuit when combined, or during use of the stack core, and if the thickness is too large, the lithium ion transmission distance is too long, the volume space ratio is too large, which affects the rate performance and volume energy density of the battery.

[0068] Similarly, the thickness of the second diaphragm layer 4 along the first direction X is also 10-15μm.

[0069] In some embodiments, as shown in FIG. 3, the depth H1 of the first groove 311 along the first direction X is 1μm-5μm. By setting the depth H1 of the first groove 311 along the first direction X to 1μm-5μm, a suitable size of the infiltration channel 5 can be formed between the first diaphragm layer 3 and the adjacent second diaphragm layer 4, and the adjacent positive electrode sheet 2 and negative electrode sheet 1 are not easy to cause contact short circuit. Figure 2 Similarly, as shown in FIG. 4, the depth H2 of the second groove 411 along the first direction X is also set to 1μm-5μm.

[0070] Figure 4 ​​​As shown, the depth H2 of the second groove 411 in the first direction X is also set to 1-5 μm. Through the cooperation of the first groove 311 and the second groove 411, an appropriate size of the infiltration channel 5 can be formed to ensure the absorption efficiency of the laminated core to the electrolyte.

[0071] In some embodiments, as shown in FIG. 1, the negative electrode sheet 1 includes a first negative electrode sheet 11 and a second negative electrode sheet 12, and the first separator layer 3 includes a first separator sub-layer 31, a second separator sub-layer 32, and a third separator sub-layer 33. Figures 1-3 As shown, the negative electrode sheet 1 includes a first negative electrode sheet 11 and a second negative electrode sheet 12, and the first separator layer 3 includes a first separator sub-layer 31, a second separator sub-layer 32, and a third separator sub-layer 33. Among them, the first negative electrode sheet 11 is arranged on the opposite sides of the laminated core in the first direction X, and the second negative electrode sheet 12 is arranged between the adjacent two positive electrode sheets 2. One side of the first negative electrode sheet 11 in the first direction X is provided with the first separator sub-layer 31, and the opposite sides of the second negative electrode sheet 12 in the first direction X are respectively provided with the second separator sub-layer 32 and the third separator sub-layer 33.

[0072] That is, the first negative electrode sheet 11 is located on the opposite sides of the laminated core in the first direction X, one side of the first negative electrode sheet 11 is adjacent to the positive electrode sheet 2, and the other side faces the outside of the laminated core. The second negative electrode sheet 12 is arranged in the middle of the laminated core between the two positive electrode sheets 2.

[0073] Correspondingly, since only one side of the first negative electrode sheet 11 is adjacent to the positive electrode sheet 2, the first separator sub-layer 31 can be arranged on one side of the first negative electrode sheet 11 to meet the requirements. Since both sides of the second negative electrode sheet 12 are adjacent to the positive electrode sheet 2, the second separator sub-layer 32 and the third separator sub-layer 33 need to be arranged on both sides of the second negative electrode sheet 12 respectively.

[0074] In some embodiments, as shown in FIG. 1, the negative electrode sheet 1 includes a first negative electrode sheet 11 and a second negative electrode sheet 12, and the first separator layer 3 includes a first separator sub-layer 31, a second separator sub-layer 32, and a third separator sub-layer 33. Figure 2 As shown, the first negative electrode sheet 11 includes a ceramic layer 111, a first negative electrode current collector layer 112, a first negative electrode material layer 113, and a first separator sub-layer 31 arranged in the first direction X. The ceramic layer 111 and the first negative electrode material layer 113 are arranged on the opposite sides of the first negative electrode current collector layer 112 in the first direction X, and the first separator sub-layer 31 is arranged on the side of the first negative electrode material layer 113 away from the first negative electrode current collector layer 112.

[0075] The first negative electrode current collector layer 112 in the first negative electrode sheet 11 serves as a carrier layer for the first negative electrode material layer 113, and has the function of conducting and collecting current. The first negative electrode material layer 113 provides negative electrode activity and participates in the battery reaction. The first separator sub-layer 31 is disposed on the side of the first negative electrode material layer 113 away from the first negative electrode current collector layer 112, and can replace the separator in the traditional technology. The ceramic layer 111 disposed on the side of the first negative electrode current collector layer 112 away from the first negative electrode material layer 113 can play the role of insulation and preventing warping, reducing the risk of short circuit between the first negative electrode current collector and other components (such as tabs) in the battery. Since the first negative electrode sheet 11 is located in the outer shell of the stacked core and adopts a single-sided coating process, it is prone to warping during use, which can lead to problems such as black spots and lithium plating. The ceramic layer 111 has a certain hardness and structural strength, which can reduce the probability of the above problems occurring.

[0076] In some embodiments, such as Figure 3 As shown, the second negative electrode 12 includes a second separator sublayer 32, a second negative electrode material layer 121, a second negative electrode current collector layer 122, a third negative electrode material layer 123, and a third separator sublayer 33 stacked along the first direction X. The second negative electrode material layer 121 and the third negative electrode material layer 123 are respectively disposed on opposite sides of the second negative electrode current collector layer 122 in the first direction X. The second separator sublayer 32 is disposed on the side of the second negative electrode material layer 121 away from the second negative electrode current collector layer 122, and the third separator sublayer 33 is disposed on the side of the third negative electrode material layer 123 away from the second negative electrode current collector layer 122.

[0077] That is, the second negative electrode 12 is located in the middle of the stacked core, and adopts the form of double-sided coating of negative electrode material (the second negative electrode material layer 121 and the third negative electrode material layer 123 are respectively provided on both sides of the second negative electrode current collector layer 122), and the second separator sub-layer 32 and the third separator sub-layer 33 are correspondingly provided.

[0078] For example, the first negative electrode current collector layer 112 and the second negative electrode current collector layer 122 may be made of copper foil. The first negative electrode material layer 113, the second negative electrode material layer 121, and the third negative electrode material layer 123 may include a negative electrode active material, a conductive agent, and a binder. The negative electrode active material may include at least one of graphite, artificial graphite, mesophase carbon microspheres, soft carbon, hard carbon, lithium titanate, and silicon-based materials; the conductive agent may include at least one of graphite, carbon nanotubes, graphene, and carbon fibers; and the binder may include at least one of polyvinylidene fluoride, styrene-butadiene rubber, sodium carboxymethyl cellulose, polyvinyl alcohol, and polyacrylic acid.

[0079] In some embodiments, the thickness of the ceramic layer 111 along the first direction X is 2μm-5μm. This ensures that warping is prevented while avoiding the problem of reduced battery volumetric energy density caused by excessive thickness.

[0080] Exemplarily, the material of the ceramic layer 111 can include a ceramic material and a binder. The ceramic material includes at least one of alumina, boehmite, zirconia, carbon-silicon oxide, and silicon dioxide, and the binder includes at least one of polyvinylidene fluoride, styrene butadiene rubber, sodium carboxymethyl cellulose, polyvinyl alcohol, and polyacrylic acid.

[0081] In some embodiments, as shown in FIG. 1, the second diaphragm layer 4 includes a fourth diaphragm sub-layer 41 and a fifth diaphragm sub-layer 42. Figure 4 The positive electrode sheet 2 includes the fourth diaphragm sub-layer 41, the first positive electrode material layer 21, the positive electrode current collector layer 22, the second positive electrode material layer 23, and the fifth diaphragm sub-layer 42 stacked along the first direction X. The first positive electrode material layer 21 and the second positive electrode material layer 23 are respectively arranged on opposite sides of the positive electrode current collector layer 22 in the first direction X, the fourth diaphragm sub-layer 41 is arranged on the side of the first positive electrode material layer 21 away from the positive electrode current collector layer 22, and the fifth diaphragm sub-layer 42 is arranged on the side of the second positive electrode material layer 23 away from the positive electrode current collector layer 22.

[0082] The positive electrode sheet 2 is arranged between two adjacent negative electrode sheets 1, and thus the positive electrode sheet 2 is double-sided coated.

[0083] Exemplarily, the first positive electrode material layer 21 and the second positive electrode material layer 23 can include a positive electrode active material, a conductive agent, and a binder. The positive electrode active material can include at least one of lithium cobaltate, lithium manganate, lithium nickelate, lithium iron phosphate, lithium nickel cobalt manganate, and lithium nickel cobalt aluminum, the conductive agent can include at least one of graphite, carbon nanotubes, graphene, and carbon fibers, and the binder can include at least one of polyvinylidene fluoride, styrene butadiene rubber, sodium carboxymethyl cellulose, polyvinyl alcohol, and polyacrylic acid.

[0084] In some embodiments, as shown in FIG. 1, the second diaphragm layer 4 includes a fourth diaphragm sub-layer 41 and a fifth diaphragm sub-layer 42. Figure 5 The positive electrode sheet 2 further includes a positive electrode tab 24 extending along the second direction Y. The positive electrode tab 24 can serve as a bridge for connecting the positive electrode sheet 2 and an external circuit.

[0085] Exemplarily, the positive electrode tab 24 can extend to the outside through a part of the positive electrode current collector. That is, the positive electrode tab 24 and the positive electrode current collector are integrally formed, which can reduce the step of welding between the positive electrode tab 24 and the positive electrode current collector, reduce the contact resistance between the positive electrode tab 24 and the positive electrode current collector, help improve the conductivity of the battery, and optimize the structure of the positive electrode sheet 2.

[0086] In some embodiments, as shown in FIG. 1, the second diaphragm layer 4 includes a fourth diaphragm sub-layer 41 and a fifth diaphragm sub-layer 42. Figure 6 The negative electrode sheet 1 further includes a negative electrode tab 114 extending along the second direction Y. Similarly, the negative electrode tab 114 can serve as a bridge for connecting the negative electrode sheet 1 and an external circuit.

[0087] Exemplarily, the negative tab 114 can extend to the outside through a part of the first negative current collector layer 112 or the second negative current collector layer 122. That is, the negative tab 114 and the first negative current collector layer 112 or the second negative current collector layer 122 are integrally formed, which can reduce the step of welding between the negative tab 114 and the first negative current collector layer 112 or the second negative current collector layer 122, reduce the contact resistance between the negative tab 114 and the first negative current collector layer 112 or the second negative current collector layer 122, help to improve the conductive performance of the battery, and optimize the structure of the negative sheet 1.

[0088] In some embodiments, as shown in FIG. 1, the positive tab 24 and the negative tab 114 are respectively arranged on opposite sides of the stack core in a certain direction. By arranging the positive tab 24 and the negative tab 114 on opposite sides of the stack core in a certain direction, the risk of short circuit caused by contact between the positive tab 24 and the negative tab 114 can be reduced. Figure 7

[0089] In a second aspect, the present application also provides a battery comprising the stack core as above. The battery provided by the embodiments of the present application has all the beneficial effects of the stack core as above, which will not be described here again.

[0090] The embodiments of the present application are described in detail above, and the principles and implementation modes of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the method of the present application and its core idea; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed, and the above description should not be understood as a limitation of the present application.​

Claims

1. A core stack, characterized in that, The negative electrode sheet and the positive electrode sheet are alternately and sequentially arranged along a first direction; At least one side of the negative electrode sheet close to the positive electrode sheet has a first diaphragm layer, and at least one side of the positive electrode sheet close to the negative electrode sheet has a second diaphragm layer; The first diaphragm layer and the second diaphragm layer are matched with each other to limit the relative displacement of the positive electrode sheet and the negative electrode sheet in a second direction; The first direction and the second direction intersect with each other.

2. The laminated core of claim 1, wherein The first diaphragm layer and the second diaphragm layer are bonded with each other to limit the relative displacement of the positive electrode sheet and the negative electrode sheet in the second direction.

3. The laminated core of claim 2, wherein The first diaphragm layer comprises a first polymer frame layer; And / or, the second diaphragm layer comprises a second polymer frame layer.

4. The laminated core of claim 1 wherein, The first diaphragm layer has a first groove and a first protrusion alternately arranged along the second direction on one side close to the second diaphragm layer; And / or, the second diaphragm layer has a second groove and a second protrusion alternately arranged along the second direction on one side close to the first diaphragm layer.

5. The core according to claim 4, wherein The first groove and the second groove correspond to each other, and the first protrusion and the second protrusion correspond to each other, so that the first groove and the second groove form an infiltration channel.

6. The core according to claim 4, wherein The width D1 of the first groove along the second direction is 1mm-2mm, and the width D2 of the first protrusion along the second direction is 1mm-2mm; And / or, the width D3 of the second groove along the second direction is 1mm-2mm, and the width D4 of the second protrusion along the second direction is 1mm-2mm.

7. The laminated core of claim 4 wherein, The thickness of the first diaphragm layer along the first direction is 10-15μm; And / or, the thickness of the second diaphragm layer along the first direction is 10-15μm.

8. The laminated core of claim 7, wherein The depth H1 of the first groove along the first direction is 1μm-5μm; And / or, the depth H2 of the second groove along the first direction is 1μm-5μm.

9. The core according to any one of claims 1 to 8, wherein The negative electrode sheet comprises a first negative electrode sheet and a second negative electrode sheet, and the first diaphragm layer comprises a first diaphragm sub-layer, a second diaphragm sub-layer and a third diaphragm sub-layer; The first negative electrode sheet is arranged on the opposite sides of the core in the first direction, and the second negative electrode sheet is arranged between two adjacent positive electrode sheets; One side of the first negative electrode sheet in the first direction is provided with the first diaphragm sub-layer, and the opposite sides of the second negative electrode sheet in the first direction are respectively provided with the second diaphragm sub-layer and the third diaphragm sub-layer.

10. The laminated core of claim 9, wherein The first negative electrode sheet comprises a ceramic layer, a first negative electrode current collector layer, a first negative electrode material layer and a first diaphragm sub-layer arranged along the first direction, and the ceramic layer and the first negative electrode material layer are arranged on the opposite sides of the first negative electrode current collector layer in the first direction, and the first diaphragm sub-layer is arranged on the side of the first negative electrode material layer away from the first negative electrode current collector layer; And / or, the second negative plate comprises the second diaphragm sublayer, the second negative electrode material layer, the second negative electrode current collector layer, the third negative electrode material layer, and the third diaphragm sublayer which are stacked along the first direction; the second negative electrode material layer and the third negative electrode material layer are respectively arranged on opposite sides of the second negative electrode current collector layer in the first direction, the second diaphragm sublayer is arranged on a side of the second negative electrode material layer away from the second negative electrode current collector layer, and the third diaphragm sublayer is arranged on a side of the third negative electrode material layer away from the second negative electrode current collector layer.

11. The laminated core of claim 10 wherein, The thickness of the ceramic layer along the first direction is 2 μm-5 μm.

12. The core according to any one of claims 1-8, wherein, The second diaphragm layer comprises a fourth diaphragm sublayer and a fifth diaphragm sublayer. The positive plate comprises the fourth diaphragm sublayer, the first positive electrode material layer, the positive electrode current collector layer, the second positive electrode material layer, and the fifth diaphragm sublayer which are stacked along the first direction. The first positive electrode material layer and the second positive electrode material layer are respectively arranged on opposite sides of the positive electrode current collector layer in the first direction, the fourth diaphragm sublayer is arranged on a side of the first positive electrode material layer away from the positive electrode current collector layer, and the fifth diaphragm sublayer is arranged on a side of the second positive electrode material layer away from the positive electrode current collector layer.

13. A battery, characterized by The core comprises any one of claims 1-12.

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