Diaphragm structure, battery cell and battery

Abstract

The invention relates to the technical field of batteries, and particularly discloses a diaphragm structure which has a first direction, a second direction and a third direction which are perpendicular to one another, the diaphragm structure is provided with an embossed area and a non-embossed area, and the non-embossed area surrounds the embossed area; in the third direction, the embossing area is provided with a plurality of embossments, and the plurality of embossments are arranged at intervals in the first direction and the second direction; in the second direction, the distance between every two adjacent knurls is L3, and the distance between every two adjacent knurls in the first direction is L4; the L3 and the L4 meet the condition that L3 is equal to L4. The invention also provides a battery cell and a battery. The knurling is arranged in the knurling area of the diaphragm structure to replace the knurling of the pole piece, so that the damage to the coating material of the pole piece can be avoided, and the knurling is arranged in the diaphragm structure to form a distance in the battery cell, so that the pores in the battery cell are improved, and the liquid retention capacity and the infiltration capacity are improved.

Description

TECHNICAL FIELD

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

[0002] The separator is a functional film material with a microporous structure and good plasticity and flexibility, which plays a role of separating the positive and negative electrodes, blocking the passage of electrons in the circuit during charging and discharging, and allowing the free passage of lithium ions in the electrolyte.

[0003] At present, the liquid retention amount of the battery cell and the distance between the pole pieces will affect the cycle energy of the battery cell and the lithium precipitation of the battery cell. At present, the main means is to form a distance by embossing on the pole piece, but the embossing of the pole piece is easy to damage the coating material particles of the pole piece, thereby affecting the cycle performance of the battery cell. At the same time, the plasticity of the pole piece itself is poor, and after embossing, concave and convex points appear on the surface of the battery cell, which is poor in appearance. SUMMARY

[0004] The technical problem to be solved by the present application is how to solve the problem of damaging the coating material of the pole piece and poor appearance after embossing caused by the embossing of the pole piece in the prior art.

[0005] In order to solve the above technical problems, the present application provides a separator structure having a first direction, a second direction and a third direction perpendicular to each other;

[0006] The separator structure has an embossed region and a non-embossed region, and the non-embossed region surrounds the embossed region;

[0007] Along the third direction, the embossed region has a plurality of embossings, and the plurality of embossings are arranged at intervals along the first direction and the second direction;

[0008] Wherein, along the second direction, the distance L3 between the two adjacent embossings, and the distance L4 between the two adjacent embossings along the first direction; and L3, L4 satisfy: L3=L4, 4.45mm≤L3≤8mm.

[0009] Further preferably, the shape of the embossing is circular, and the diameter of the embossing is D;

[0010] The diameter D satisfies: 0.8mm≤D≤1.5mm.

[0011] Further preferably, the width of the non-embossed region along the first direction is L1, and the width of the embossed region along the first direction is L2;

[0012] Wherein, the width L1, L2 satisfies: 5mm≤(L1-L2) / 2≤8mm.

[0013] Further preferably, a width of the embossed region along the first direction is L2, and L2 satisfies: 30mm≤L2≤60mm.

[0014] Further preferably, along the third direction, a depth of the embossing is L5.

[0015] The depth L5 satisfies: 0.8pm≤L5≤1.2pm.

[0016] Further preferably, along the third direction, a thickness of the embossing is L6.

[0017] The thickness L6 satisfies: 0.8pm≤L6≤1.2pm.

[0018] Further preferably, the embossed shape is one or more of a circle, a stripe, a plum blossom, or a rectangle.

[0019] Further preferably, the separator structure is any one of a polyolefin separator, a cellulose separator, or a composite separator.

[0020] The application also provides a battery cell, comprising an anode sheet, a cathode sheet, and the separator structure as described above.

[0021] The separator structure is arranged between the anode sheet and the cathode sheet, and the anode sheet, the cathode sheet, and the separator structure are laminated to form the battery cell.

[0022] The application also provides a battery, comprising the battery cell as described above.

[0023] The separator structure, the battery cell, and the battery provided by the application have the following beneficial effects compared with the prior art:

[0024] Firstly, the embossing is arranged on the embossed region of the separator structure, which can replace the embossing of the electrode sheet, avoid damaging the coating material of the electrode sheet, and form a distance in the battery cell by arranging the embossing on the separator structure, thereby improving the porosity in the battery cell, the liquid retention capacity, and the wettability.

[0025] Secondly, the distance L3 between two adjacent embossings along the second direction is equal to the distance L4 between two adjacent embossings along the first direction, which can ensure the uniformity of the porosity in the battery cell, thereby ensuring the liquid retention capacity and the wettability of the battery cell.

[0026] Furthermore, since the separator structure has high plasticity, the embossing on the separator structure will not damage the separator, and the embossing on the electrode sheet will not affect the integrity and the appearance of the electrode sheet. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1This is a schematic diagram of the diaphragm structure described in this invention.

[0028] Figure 2 This is the present invention. Figure 1 A sectional view of section AA in the middle.

[0029] Figure 3 This is a schematic diagram of the structure of multiple diaphragm structures of the present invention connected as one unit.

[0030] Figure label:

[0031] 10. Diaphragm structure; 10a. Embossed area; 10b. Non-embossed area; 11. Embossed;

[0032] X, first direction; Y, second direction; Z, third direction. Detailed Implementation

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0034] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0035] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" used to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0036] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0037] Furthermore, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection; can be direct connection, can also be indirect connection through intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0038] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0039] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there can be a mediating element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there can be a mediating element. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not the only implementation.

[0040] As shown in Figures 1-2 The present application provides a diaphragm structure having a first direction X, a second direction Y and a third direction Z perpendicular to each other.

[0041] In the specific embodiment, the diaphragm structure 10 has an embossed region 10a and a non-embossed region 10b, and the non-embossed region 10b surrounds the embossed region 10a.

[0042] In some embodiments, along the third direction Z, the embossed region 10a is provided with a plurality of embossments 11, and the plurality of embossments 11 are arranged at intervals along the first direction X and the second direction Y; wherein along the second direction Y, the distance L3 between two adjacent embossments 11, along the first direction X, the distance L4 between two adjacent embossments 11; and L3, L4 satisfy: L3=L4, so that by arranging embossments 11 on the embossed region 10a of the diaphragm structure 10, the pole piece embossing can be replaced, the pole piece coating material can be prevented from being damaged, and the embossments 11 arranged on the diaphragm structure 10 can form a distance inside the battery cell, thereby improving the porosity inside the battery cell, improving the liquid retention capacity and wettability; secondly, the distance L3 between two adjacent embossments 11 along the second direction Y is equal to the distance L4 between two adjacent embossments 11 along the first direction X, which can ensure the uniformity of the porosity inside the battery cell, thereby ensuring the liquid retention capacity and wettability of the battery cell; furthermore, since the diaphragm structure 10 has high plasticity, the embossing on the diaphragm structure 10 will not damage the diaphragm, and the embossing on the pole piece will not affect the integrity and aesthetics of the pole piece.

[0043] In some embodiments, along the second direction Y, the distance L3 between two adjacent embossments 11 satisfies: 4.45mm≤L3≤8mm. Wherein, L3≤8mm can accelerate the penetration of electrolyte into the diaphragm, shorten the infiltration time by more than 30%; L3≥4.45mm can provide a lateral diffusion buffer for electrolyte, reduce local concentration polarization, and provide a deformation space to prevent the diaphragm from wrinkling and cracking.

[0044] In addition, the plurality of embossments 11 are arranged in a matrix, and the protrusions formed by the embossments on the diaphragm can form flow guide grooves, so that lithium ions can be transmitted along a low-resistance path, the membrane resistance can be reduced, and the rate performance can be improved.

[0045] In some embodiments, the embossments 11 are circular in shape, and the diameter of the embossments 11 is D; the diameter D satisfies: 0.8mm≤D≤1.5mm. The embossments with this diameter range form a nanoscale pore gradient, which promotes faster diffusion and uniform distribution of electrolyte, reduces infiltration time, and avoids battery polarization problems caused by local dry areas; in addition, 1.5mm diameter embossment points anchor the diaphragm structure, with a shrinkage rate of <5% at high temperatures, which can relieve electrode expansion stress and prolong cycle life.

[0046] In some embodiments, the non-embossed region 10b has a width L1 along the first direction X, and the embossed region 10a has a width L2 along the first direction X; wherein the widths L1, L2 satisfy: 5mm≤(L1-L2) / 2≤8mm. In this way, by limiting the ratio of the embossed region 10a to the total area of the separator structure 10, the embossing in the embossed region 10a can form a network-distributed support structure, effectively intercepting dendrite growth and reducing the risk of short circuit caused by membrane creases or breakage in the cycle; and the embossed region 10a and the non-embossed region 10b can form a pore gradient, accelerating the electrolyte diffusion speed, while reducing local concentration polarization and improving ionic conductivity.

[0047] In some embodiments, the width L2 of the embossed region 10a along the first direction X satisfies: 30mm≤L2≤60mm. The 30-60mm wide embossed band forms a continuous physical barrier, which can intercept multi-directional dendrite penetration and improve the wetting speed.

[0048] In some embodiments, along the third direction Z, the depth of the embossing 11 is L5; wherein the depth L5 satisfies: 0.8μm≤L5≤1.2μm, and the thickness of the embossing 11 is L6; wherein the thickness L6 satisfies: 0.8μm≤L6≤1.2μm. This depth and thickness range can effectively intercept early lithium dendrites, avoid lithium precipitation, and form a network of physical barriers; at the same time, it maintains the overall lightweight requirement of the separator, avoiding ion migration obstruction caused by excessive thickening; in addition, the embossed region depth of 0.8-1.2μm can improve the electrolyte retention amount, while avoiding excessive pore size leading to dendrite penetration.

[0049] In some embodiments, the embossing 11 is one or more of circular, striped, plum blossom-shaped, or rectangular. The shape of the embossing 11 can be achieved by designing the embossing roller; using a circular embossing shape, the circular arc edge can eliminate stress concentration points and reduce the breakage rate under cyclic expansion; the striped embossing can build a longitudinal interception network for dendrites to avoid lithium precipitation in the battery, and the striped direction can guide lithium ions to migrate along a low-resistance path, reducing the internal resistance of the separator; the plum blossom-shaped embossing can achieve gradient distribution of electrolyte, further improve the liquid retention amount, and improve the cycle energy of the battery and avoid lithium precipitation in the battery; the rectangular embossing array can effectively improve the protection area.

[0050] In some embodiments, the separator structure 10 is any one of a polyolefin separator, a cellulose separator, or a composite separator. The polyolefin separator (such as PE or PP) can withstand internal battery pressure and environmental changes, prevent short circuits, and ensure safe operation of the battery; the cellulose separator has high ionic conductivity and thermal stability, and its nanoscale pore structure can adsorb electrolyte to form a continuous ion channel, significantly improving the battery rate performance; the composite separator combines inorganic (such as alumina) and organic materials (such as aramid), which can balance ionic conductivity and chemical stability, and is suitable for high-power or extreme environments.

[0051] Need to explain, polyolefin separator or cellulose separator or composite separator is the existing separator, and all have plasticity, can meet the embossing of the separator.

[0052] In summary, the present application provides a kind of separator structure, by setting embossing 11 in the embossed area 10a of separator structure 10, to replace pole piece embossing, can avoid destroying pole piece coating material, and the distance can be formed in the separator structure 10 setting embossing 11 inside battery, further improve the porosity of battery inside, improve liquid retention and wetting capacity;Second, the distance L3 between two embossing 11 adjacent along the second direction Y is equal to the distance L4 between two embossing 11 adjacent along the first direction X, can guarantee the uniformity of the porosity of battery, to ensure the liquid retention and wetting capacity of battery;Further, since separator structure 10 has high plasticity, the present application is embossed on separator structure 10, and will not cause damage to separator, avoid the influence of embossing on pole piece on the integrity and aesthetics of pole piece.

[0053] The present application also provides a kind of battery, including anode sheet, cathode sheet and the separator structure as described in the above embodiment;Separator structure is arranged between anode sheet and cathode sheet, and anode sheet, cathode sheet and separator structure are laminated to form battery.The specific structure of the pole piece structure is referred to the above embodiment, since the battery uses all the technical solutions of the above all embodiments, at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0054] Need to explain, battery mainly relies on metal ion to move between anode pole piece and cathode pole piece to work.Anode pole piece includes anode current collector and anode active material layer, and anode current collector has coating area and anode lug connected to coating area, and anode active material layer is coated on the surface of anode current collector.

[0055] In some embodiments, as shown in Figure 3 A plurality of separator structures 10 are connected to form a whole, and there is a crease between adjacent two separator structures 10, to realize the separation of anode sheet and cathode sheet by folding, and realize the lamination between anode sheet, cathode sheet and separator structure.

[0056] The present application also provides a kind of battery, including shell and the battery as described in the above embodiment, and the shell covers battery.The specific structure of the battery is referred to the above embodiment, since the battery uses all the technical solutions of the above all embodiments, at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0057] Battery refers to a cup, a groove or other container (such as a shell) or part of the space of a composite container containing electrolyte solution and metal electrodes to generate current, a device that can convert chemical energy into electrical energy; batteries are divided into anodes and cathodes. With the progress of science and technology, batteries refer to small devices that can generate electrical energy, such as solar cells. The performance parameters of the battery mainly include electromotive force, capacity, specific energy and resistance. Battery principle: In a chemical battery, the direct conversion of chemical energy into electrical energy is the result of spontaneous oxidation and reduction reactions inside the battery. These reactions occur at two electrodes.

[0058] Taking a lithium battery as an example, the material of the cathode current collector can be aluminum, and the cathode active material layer can be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate. The material of the anode current collector can be copper, and the anode active material layer can be a carbon-based material (such as graphite) or a silicon-based material and an alloy material. The material of the separator can be PP (polypropylene) or PE (polyethylene). The electrolyte is a material with good ionic conductivity, such as an acid, a base, a salt solution, an organic or inorganic non-aqueous solution, a molten salt or a solid electrolyte.

[0059] In other embodiments, the battery can be a rechargeable battery, also known as a charging battery or a storage battery, which refers to a battery that can be activated by charging after discharging. By utilizing the reversibility of chemical reactions, a new battery can be assembled, that is, after a chemical reaction is converted into electrical energy, the chemical system can be repaired using electrical energy, and then the chemical reaction can be converted into electrical energy, so it is called a secondary battery (rechargeable battery).

[0060] The application also provides a power-using device comprising the above battery, and the specific structure of the battery is referred to the above embodiments. Since the power-using device adopts all the technical solutions of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0061] The electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle can be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile, or a range extended automobile, etc. The spacecraft includes an airplane, a rocket, a space shuttle, a spacecraft, etc. The electric toy includes a fixed or mobile electric toy, such as a game console, an electric automobile toy, an electric ship toy, an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool, and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator, an electric planer, etc. The electric device is not specially limited in the embodiment.

[0062] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, several improvements and replacements can be made without departing from the technical principles of the present application, and these improvements and replacements should also be considered as the protection scope of the present application. The basic principles, main features, and advantages of the present application are shown and described above, and it is obvious for those skilled in the art that the present application is not limited to the details of the preferred embodiments, and the embodiments should be considered as exemplary and non-limiting, the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims should be included in the present application.

[0063] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in the embodiments can also be properly combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A separator structure having a first direction, a second direction and a third direction perpendicular to each other, characterized in that: the separator structure has an embossed region and a non-embossed region, and the non-embossed region surrounds the embossed region; in the third direction, the embossed region is provided with a plurality of embossings, and the plurality of embossings are arranged at intervals in the first direction and the second direction; wherein, in the second direction, the distance L3 between two adjacent embossings, and in the first direction, the distance L4 between two adjacent embossings; and L3, L4 satisfy: L3=L4, 4.45mm≤L3≤8mm.

2. The membrane structure of claim 1, wherein, the embossing shape is circular, and the diameter of the embossing is D; the diameter D satisfies: 0.8mm≤D≤1.5mm.

3. The membrane structure of claim 1, wherein, the width of the non-embossed region in the first direction is L1, and the width of the embossed region in the first direction is L2; wherein, the widths L1, L2 satisfy: 5mm≤(L1-L2) / 2≤8mm.

4. A membrane structure according to claim 3, wherein the width L2 of the embossed region in the first direction satisfies: 30mm≤L2≤60mm.

5. The membrane structure of claim 1, wherein in the third direction, the depth of the embossing is L5; wherein, the depth L5 satisfies: 0.8μm≤L5≤1.2μm.

6. The membrane structure of claim 1, wherein in the third direction, the thickness of the embossing is L6; wherein, the thickness L6 satisfies: 0.8μm≤L6≤1.2μm.

7. The membrane structure of claim 1, wherein the embossing shape is one or more of circular, stripe, plum blossom or rectangular.

8. The membrane structure of claim 1, wherein, the separator structure is any one of a polyolefin separator, a cellulose separator or a composite separator.

9. An electric cell characterized by an anode sheet, a cathode sheet and the separator structure according to any one of claims 1-8; the separator structure is arranged between the anode sheet and the cathode sheet, and the anode sheet, the cathode sheet and the separator structure are laminated to form the battery cell.

10. A battery, characterized by a battery cell comprising the battery cell according to claim 9.

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