Anti-precipitation lithium battery cell and anti-precipitation lithium battery

Abstract

The utility model provides an anti-precipitation lithium battery core and an anti-precipitation lithium battery, which comprise a first pole piece, a diaphragm and a second pole piece, the first pole piece, the diaphragm and the second pole piece are sequentially laminated and wound into a roll core; a first liquid absorption layer is arranged on one surface, facing the first pole piece, of the diaphragm, a ceramic layer is arranged on one surface, facing the second pole piece, of the diaphragm, the ceramic layer is used for fixing the shape of the diaphragm, a second liquid absorption layer is arranged on one surface, back to the diaphragm, of the ceramic layer, and the ceramic layer is used for fixing the shape of the diaphragm. The first liquid absorption layer and the second liquid absorption layer are used for absorbing electrolyte, and both the first liquid absorption layer and the second liquid absorption layer have elasticity. According to the anti-precipitation lithium battery cell disclosed by the utility model, the pole pieces in the battery cell can be effectively prevented from being broken.

Description

Technical Field

[0001] This utility model relates to the field of new energy technology, and in particular to an anti-lithium-plating battery cell and an anti-lithium-plating battery. Background Technology

[0002] With continuous technological advancements and innovation, the demand for various smart devices, especially smartphones and computers, is growing daily. The widespread adoption of these devices has led to higher requirements for the performance and safety of smart products. Among numerous performance indicators, energy density and safety have become the primary focus for both consumers and manufacturers. To meet these demands, higher coating weights and compaction are employed, posing increasing challenges to the charging capacity of the system, especially at weak corners where lithium plating is particularly prone to occur later in the cycle, significantly impacting the safety and reliability of the battery cell. Current technologies typically involve applying coatings to the separator to improve the cell's liquid retention capacity and reduce lithium plating. However, when coating the separator, it is prone to deformation and even breakage. This can lead to direct contact between the active materials at the anode and cathode, causing a short circuit within the cell. Therefore, the shape of the separator needs to be fixed. During battery cell use, cyclic charging and discharging cause the electrodes on both sides of the separator to expand, generating significant internal stress that can lead to electrode breakage. Therefore, a battery cell design that prevents electrode breakage is needed. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an anti-lithium plating battery cell, which can effectively prevent the electrode plates in the battery cell from breaking.

[0004] This utility model also proposes an anti-lithium plating battery.

[0005] According to a first aspect of the present invention, an anti-lithium plating battery cell includes: a first electrode, a separator, and a second electrode, wherein the first electrode, the separator, and the second electrode are sequentially stacked and wound into a core; a first liquid-absorbing layer is provided on the side of the separator facing the first electrode, and a ceramic layer is provided on the side of the separator facing the second electrode, the ceramic layer being used to fix the shape of the separator, and a second liquid-absorbing layer is provided on the side of the ceramic layer facing away from the separator; the first liquid-absorbing layer and the second liquid-absorbing layer are used to absorb electrolyte, and both the first liquid-absorbing layer and the second liquid-absorbing layer are elastic.

[0006] The lithium-ion battery cell according to the first aspect of the present invention has at least the following beneficial effects: by setting a ceramic layer on the separator, the hardness of the separator is increased and the shape of the separator is fixed, thereby avoiding separator deformation and preventing the first electrode from directly contacting the second electrode, thus preventing short circuits inside the battery cell. At the same time, by setting a first liquid-absorbing layer and a second liquid-absorbing layer respectively, while preserving the electrolyte and preventing lithium deposition in the battery cell, gaps are formed on both sides of the separator, so that the first electrode and the second electrode have sufficient space when they expand, which effectively prevents the first electrode and the second electrode from breaking and also prevents the separator from being squeezed and deformed.

[0007] According to some embodiments of the present invention, both the first liquid-absorbing layer and the second liquid-absorbing layer are pore-forming materials. The pore-forming material includes pore-forming particles and a binder. The pore-forming particles and the binder are mixed and coated on the ceramic layer to form the second liquid-absorbing layer. The pore-forming particles and the binder are mixed and coated on the diaphragm to form the first liquid-absorbing layer.

[0008] According to some embodiments of the present invention, the ceramic layer includes one of aluminum oxide, silicon dioxide, magnesium hydroxide, boehmite, zirconium dioxide, calcium oxide, and zinc oxide.

[0009] According to some embodiments of this utility model, the pore-forming particles are polymethyl methacrylate aggregates, the binder is polyvinylidene fluoride, the weight percentage of the pore-forming particles is no more than 10%, and the areal density of the mixed solution coated on the ceramic layer is no less than 0.05 g / m² and no more than 5 g / m².

[0010] According to some embodiments of the present invention, the adhesion force of the first liquid-absorbing layer and the second liquid-absorbing layer is not less than 0.5 N / m.

[0011] According to some embodiments of the present invention, the thickness of both the first liquid-absorbing layer and the second liquid-absorbing layer is not less than 0.5 μm and not more than 10 μm.

[0012] According to some embodiments of the present invention, the volume of the first absorbent layer is A, the volume of electrolyte that the first absorbent layer can hold is B, and B / A is not less than 0.97%.

[0013] According to some embodiments of the present invention, the thickness of the ceramic layer is not less than 0.1 μm and not more than 2 μm.

[0014] According to some embodiments of this utility model, the particle size of the pore-forming particles does not exceed 200 μm.

[0015] According to a second aspect of the present invention, the lithium-plating-resistant battery is characterized in that it includes the lithium-plating-resistant battery cell described in any one of the above embodiments.

[0016] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] Figure 1 This is a schematic cross-sectional view of the diaphragm in an anti-lithium plating battery cell according to the present invention;

[0018] Figure 2 This is a schematic diagram of the core structure of an anti-lithium plating battery cell according to the present invention;

[0019] Figure 3 This is a cross-sectional schematic diagram of an anti-lithium plating battery cell according to the present invention.

[0020] Icon labels:

[0021] 1. First electrode; 2. Diaphragm; 3. Second electrode; 4. Ceramic layer; 5. First absorbent layer; 6. Second absorbent layer. Detailed Implementation

[0022] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0023] In the description of this utility model, it should be understood that the orientation descriptions, such as up and down, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0024] In the description of this utility model, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features or their sequential relationship.

[0025] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0026] The energy density of a battery cell refers to the energy that can be stored per unit volume or unit mass of the cell. It is usually expressed in watt-hours per liter (Wh / L) for volumetric energy density and in watt-hours per kilogram (Wh / kg) for gravimetric energy density. Higher energy density means the cell can store more electrical energy per unit volume or mass, which is crucial for applications such as portable electronic devices and electric vehicles. How is the energy density of a battery cell calculated? The energy density of a battery cell, i.e., the energy stored per unit volume or unit mass of the battery, is one of the key indicators for measuring battery performance. It is influenced by a variety of complex factors, spanning a wide range of fields from materials science to engineering design. First, the chemical composition of the cell is the core factor affecting energy density. Different cathode materials, such as lithium cobalt oxide (LiCoO2), lithium nickel cobalt manganese oxide (NCM), or lithium iron phosphate (LFP), have different energy storage capacities. Anode materials, such as graphite or silicon-based materials, also affect the overall energy density due to their different electrochemical properties. The choice of electrolyte and the material of the separator are equally important, as they determine the efficiency and safety of ion transport within the battery. Design and manufacturing processes are also crucial factors affecting energy density. The battery's structural design, including electrode thickness, active material loading, and packaging method, significantly impacts energy density. For example, thinner electrodes reduce the use of inactive materials, thus increasing energy density per unit volume. The precision of the manufacturing process, such as coating uniformity, compaction density, and assembly accuracy, all affect battery performance. Furthermore, material quality and purity also have a significant impact on energy density. High-purity materials reduce internal side reactions and improve energy utilization. The microstructure of materials, such as particle size and distribution, also affects the surface area of ​​electrode materials and ion diffusion paths, thereby influencing the battery's charge and discharge performance.

[0027] Electrolytes play a crucial role in batteries, serving not only as a medium for charge transfer but also as a key to the smooth operation of internal chemical reactions. Electrolytes are typically composed of a specific solvent and dissolved electrolyte salts, and the choice of materials directly impacts battery performance. In rechargeable batteries, the role of the electrolyte is particularly significant. It participates in the electrochemical reactions during charging and discharging and is responsible for efficiently transporting ions between the positive and negative electrodes, ensuring a smooth conversion between electrical and chemical energy. Taking lithium-ion batteries as an example, the electrolyte is usually composed of a series of carbonate solvents and lithium salts. These carbonate solvents, such as ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC), have good chemical stability and can withstand the high-temperature environment generated during charging and discharging. Lithium salts, such as lithium hexafluorophosphate (LiPF6), provide the necessary lithium ions, which shuttle between the positive and negative electrodes inside the battery, enabling the battery to store and release energy. The importance of electrolytes lies not only in their ability to ensure the smooth movement of ions during charging and discharging, but also in their contribution to the overall stability and safety of the battery. A well-designed electrolyte can reduce side reactions, extend battery life, and provide necessary protection under extreme conditions, preventing overheating or dangerous chemical reactions. Therefore, meticulous selection and optimization of electrolyte materials and properties during battery design and manufacturing are crucial steps in ensuring efficient, safe, and long-term stable battery operation. Consequently, during battery operation, it is essential to ensure that the electrodes are fully wetted by the electrolyte.

[0028] As the battery cycles through charging and discharging, the cell electrodes expand, squeezing the interfaces and corners. This is especially true in silicon systems, where the adhesion between the oily separator and the electrodes is too strong, leaving no interfacial gaps. The anode sheet expands too much, and there are no gaps to alleviate the expansion. The corners are squeezed first, leading to electrolyte breakage, black spots on the electrodes, and lithium plating. In severe cases, the electrodes may even break, reducing the battery's cycle performance and safety, thus shortening its lifespan.

[0029] Reference Figure 1 , Figure 2 and Figure 3The lithium-ion battery cell according to the first embodiment of this utility model includes: a first electrode 1, a separator 2, and a second electrode 3. The first electrode 1, separator 2, and second electrode 3 are stacked and wound into a core. A first absorbent layer 5 is provided on the side of the separator 2 facing the first electrode 1, and a ceramic layer 4 is provided on the side of the separator 2 facing the second electrode 3. The ceramic layer 4 is used to fix the shape of the separator 2. A second absorbent layer 6 is provided on the side of the ceramic layer 4 facing away from the separator 2. The first absorbent layer 5 and the second absorbent layer 6 are used to absorb electrolyte. Both the first absorbent layer 5 and the second absorbent layer 6 are elastic. In high-energy-density battery cells, the electrodes are hot-pressed relatively tightly. In such a tight environment, it is difficult for the electrolyte to fully penetrate the electrodes. Therefore, it is necessary to provide a first absorbent layer 5 and a second absorbent layer 6 on the separator 2 to retain sufficient electrolyte between the first electrode 1 and the second electrode 3. To prevent the diaphragm 2 from deforming after heating, a ceramic layer 4 is provided on the diaphragm 2 to fix its shape, preventing deformation that could lead to direct contact between the first electrode 1 and the second electrode 3. Direct contact between the first electrode 1 and the second electrode 3 would cause a short circuit in the battery cell. A first absorbent layer 5 and a second absorbent layer 6 are respectively provided on the opposite side of the diaphragm 2 and the ceramic layer 4. When the first electrode 1 and the second electrode 3 expand, they compress the first absorbent layers 5 and 6, causing them to elastically contract and preventing excessive stress on the first electrode 1 and the second electrode 3, thus preventing breakage. Furthermore, the first absorbent layer 5 and the second absorbent layer 6 are provided on both sides of the diaphragm 2, allowing gaps to be formed on both sides to accommodate the first electrode 1 and the second electrode 3, preventing deformation of the diaphragm 2 due to compression on one side. When only the first absorbent layer 5 or the second absorbent layer 6 is provided on the diaphragm 2, a gap can only be formed on one side of the diaphragm 2. When the first electrode 1 and the second electrode 3 expand, they simultaneously compress both sides of the diaphragm 2. The side of the diaphragm 2 without gaps will directly press against the diaphragm 2, which will cause the diaphragm 2 to deform or even break. Therefore, it is necessary to set an elastic first liquid-absorbing layer 5 and a second liquid-absorbing layer 6 on both sides of the diaphragm 2 to protect the diaphragm 2 from deformation and prevent the first electrode 1 and the second electrode 3 from breaking.

[0030] In wound battery cells, to increase the energy density, the active material is pressed more tightly, and the electrodes are also pressed more tightly together. This makes it difficult for the electrolyte to fully penetrate the electrodes, preventing them from discharging completely and leading to lithium plating. Therefore, a first wicking layer 5 and a second wicking layer 6 are needed between the first electrode 1 and the second electrode 3 to store the electrolyte, ensuring sufficient electrolyte between them. Simultaneously, the first wicking layer 5 and the second wicking layer 6 also have adhesive properties to firmly adhere the separator 2 to the first electrode 1 and the second electrode 3. Furthermore, the first wicking layer 5 and the second wicking layer 6 can elastically deform, providing space for the expansion of the first electrode 1 and the second electrode 3 when they expand, preventing them from being squeezed together and breaking.

[0031] According to some embodiments of this utility model, both the first liquid-absorbing layer 5 and the second liquid-absorbing layer 6 are pore-forming materials. The pore-forming material includes pore-forming particles and a binder. The pore-forming particles and binder are mixed and coated onto the ceramic layer 4 to form the second liquid-absorbing layer 6. The pore-forming particles and binder are mixed and coated onto the diaphragm 2 to form the first liquid-absorbing layer 5. After the pore-forming particles and binder are mixed, the pore-forming particles can be fixed onto the ceramic layer 4 and the diaphragm 2. At this time, gaps are formed between the pore-forming particles, and electrolyte can be retained in these gaps, thus forming the first liquid-absorbing layer 5 and the second liquid-absorbing layer 6. Simultaneously, the pore-forming particles are elastic and can undergo elastic deformation, thereby providing space for the first electrode 1 and the second electrode 3 when they expand. The pore-forming particles can be agglomerated particles such as acrylic balls or polyethylene. The pore-forming particles themselves have a certain degree of viscosity. To adjust the gaps and adhesion in the pore-forming material, the ratio and type of the pore-forming particles and binder are adjusted.

[0032] According to some embodiments of this utility model, the ceramic layer 4 includes one of aluminum oxide, silicon dioxide, magnesium hydroxide, boehmite, zirconium dioxide, calcium oxide, and zinc oxide. Firstly, the ceramic layer 4 has high-temperature resistance; it will not deform after being subjected to high temperatures. Simultaneously, when the separator 2 is affected by high temperatures, the ceramic layer 4 can also prevent the separator 2 from deforming, thereby avoiding direct contact between the first electrode 1 and the second electrode 3, thus greatly reducing the risk of short circuits in the battery cell. The ceramic layer 4 is used to fix the shape of the separator 2. Materials such as aluminum oxide, silicon dioxide, magnesium hydroxide, boehmite, zirconium dioxide, calcium oxide, and zinc oxide not only do not react within the battery cell, but also, after being coated on the separator 2, can form a fixed shape and fix the separator 2.

[0033] According to some embodiments of this utility model, the pore-forming particles are polymethyl methacrylate (PMMA) aggregates, the binder is polyvinylidene fluoride (PVDF), and the weight percentage of the pore-forming particles does not exceed 10%. The areal density of the mixed solution coated on the ceramic layer 4 is not less than 0.05 g / m² and not more than 5 g / m². When the proportion of pore-forming particles is too high, the first liquid-absorbing layer 5 and the second liquid-absorbing layer 6 will become too thick, and the adhesion of the pore-forming material will decrease. Therefore, the proportion of pore-forming particles and the coating density of the pore-forming material are limited to ensure that the formed pore-forming material has an appropriate thickness and gap. Different pore-forming particles have different adhesion, so the ratio of different pore-forming particles to binder is different. When the pore-forming particles are PMMA aggregates and PVDF is used as the binder, the weight percentage of the pore-forming particles does not exceed 10%, which is sufficient to ensure that the pore-forming material has good adhesion and liquid absorption capacity, as well as good elastic deformation capacity.

[0034] According to some embodiments of this utility model, the adhesion force of both the first liquid-absorbing layer 5 and the second liquid-absorbing layer 6 is not less than 0.5 N / m. If the adhesion force of the first liquid-absorbing layer 5 and the second liquid-absorbing layer 6 is too small, the pore-forming material will detach. Therefore, the adhesion force of the pore-forming material is limited to above 0.5 N / m to prevent the pore-forming material from detaching from the diaphragm 2 or the ceramic layer 4. This allows the diaphragm 2 to be firmly adhered to the first electrode 1 and the second electrode 3.

[0035] According to some embodiments of this utility model, the thickness of the first liquid-absorbing layer 5 and the second liquid-absorbing layer 6 is not less than 0.5 μm and not more than 10 μm. After coating the pore-forming material onto the separator 2 or the ceramic layer 4, the first liquid-absorbing layer 5 and the second liquid-absorbing layer 6 are pressed to make their thicknesses between 0.5 μm and 10 μm, thereby improving the energy density of the battery cell while ensuring the function of the first liquid-absorbing layer 5 and the second liquid-absorbing layer. However, when the thickness of the first liquid-absorbing layer 5 and the second liquid-absorbing layer 6 is large, air bubbles are easily generated in the gaps between the first liquid-absorbing layer 5 and the second liquid-absorbing layer 6, which prevents the electrolyte from completely penetrating the first liquid-absorbing layer 5 and the second liquid-absorbing layer 6, resulting in a broken bridge phenomenon in the first liquid-absorbing layer 5 and the second liquid-absorbing layer 6, thus leading to deterioration of lithium plating. Therefore, the thickness of the first liquid-absorbing layer 5 and the second liquid-absorbing layer 6 is limited to less than 10 μm.

[0036] According to some embodiments of this utility model, the volume of the first liquid-absorbing layer 5 is A, and the volume of electrolyte that the first liquid-absorbing layer 5 can hold is B, where B / A is not less than 0.97%. This ensures that the volume of the gaps in the first liquid-absorbing layer 5 is sufficient to hold enough electrolyte, thus avoiding lithium plating caused by insufficient electrolyte.

[0037] According to some embodiments of this utility model, the thickness of the ceramic layer 4 is not less than 0.1 μm and not more than 2 μm. A larger thickness of the ceramic layer 4 will reduce the energy density of the battery cell, while a smaller thickness of the ceramic layer 4 will not be able to guarantee the shape of the separator 2. Therefore, the thickness of the ceramic layer 4 is limited to between 0.1 μm and 2 μm.

[0038] According to some embodiments of this invention, the particle size of the pore-forming particles does not exceed 200 μm. The pore-forming particles can be spherical or elliptical. When the particle size is large, the gaps in the pore-forming material decrease, resulting in less electrolyte being stored within the material. Therefore, it is necessary to limit the particle size of the pore-forming particles to below 200 μm to increase the gaps within the particles, thereby improving the electrolyte storage capacity of the pore-forming material.

[0039] According to a second aspect of the present invention, the lithium-plating-resistant battery is characterized in that it includes any of the lithium-plating-resistant cells described in the above embodiments.

[0040] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A lithium precipitation preventing battery cell, characterized by, The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell.

2. The lithium plating prevention battery cell of claim 1, wherein, The application relates to a lithium battery cell.

3. The lithium plating prevention battery cell of claim 1, wherein, The application relates to a lithium battery cell.

4. The lithium plating prevention cell of claim 1, wherein The application relates to a lithium battery cell.

5. The lithium plating prevention cell of claim 1, wherein, The application relates to a lithium battery cell.

6. The lithium plating prevention cell of claim 1, wherein, The application relates to a lithium battery cell.

7. The lithium plating prevention cell of claim 1, wherein The application relates to a lithium battery cell.

8. A lithium precipitation preventing battery, characterized by The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application relates to a lithium battery cell. The application

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