Composite plasticizers, electrode slurries, and uses
By leveraging the synergistic effect of 1,3-butanediol and monohydric or ortho-diol in the composite plasticizer, the problem of the difficult volatilization of 1,3-butanediol was solved, achieving efficient crack suppression of electrode sheets and rapid volatilization of plasticizer, thereby improving the production yield and battery performance of lithium-ion batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUNGROW POWER SUPPLY CO LTD
- Filing Date
- 2026-05-07
- Publication Date
- 2026-08-04
AI Technical Summary
In existing lithium-ion batteries, 1,3-butanediol is used as a plasticizer, but it is difficult to completely volatilize, which leads to cracking of the electrode surface, electrolyte consumption, and decreased battery performance. It is difficult to balance crack prevention, plasticizer volatility, battery energy density, and mass production feasibility.
A composite plasticizer is used, including a first plasticizer 1,3-butanediol and a second plasticizer monohydric alcohol or ortho-diol. By disrupting the hydrogen bond network of 1,3-butanediol, the volatilization efficiency is improved and the surface tension is reduced, thereby inhibiting cracking.
Significantly reduces plasticizer residue, improves electrode yield, ensures plasticizing effect, and meets production requirements under thick coating and high coating speed conditions.
Smart Images
Figure CN122511901A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery technology, and in particular to a composite plasticizer, electrode slurry, and its use. Background Technology
[0002] With the widespread application of lithium-ion batteries in 3C digital products, electric vehicles, and large-scale energy storage, improving battery energy density and reducing manufacturing costs have become core R&D directions. In battery manufacturing, increasing the thickness of the electrode coating layer and improving the coating speed are important technical paths to achieve cost reduction and efficiency improvement. However, in aqueous electrode coating processes, as the coating thickness and coating speed increase, the wet coating will generate significant internal stress during the drying process due to the rapid evaporation of solvents and the severe shrinkage of the adhesive film. This can easily lead to defects such as microcracks and powder shedding on the electrode surface, severely restricting the production yield of the electrode.
[0003] To address these issues, traditional techniques typically introduce plasticizers during the electrode slurry bonding process to improve electrode flexibility. 1,3-Butanediol, due to its good compatibility with electrode binders and its ability to effectively reduce solvent surface tension at the end of drying, is widely used to suppress drying stress and coating cracking. However, because 1,3-butanediol readily forms strong hydrogen bond networks between its molecules, it is difficult to completely evaporate and remove it under conventional baking processes. This results in excessive 1,3-butanediol residues in the battery cell, which not only consumes electrolyte and affects interfacial stability but may also degrade the kinetic performance and long-term cycle reliability of lithium-ion batteries. Summary of the Invention
[0004] This application provides a composite plasticizer, an electrode paste, and its use. The second plasticizer disrupts the hydrogen bond association network of the first plasticizer, thereby effectively reducing plasticizer residue while inhibiting surface cracking of the electrode.
[0005] To achieve the above objectives, the first aspect of this application provides a composite plasticizer for use in electrode paste, comprising: a first plasticizer and a second plasticizer; wherein the first plasticizer comprises: 1,3-butanediol; and the second plasticizer comprises: at least one of a monohydric alcohol and an ortho-diol.
[0006] In this application, a composite plasticizer is provided for use in electrode paste, comprising a first plasticizer and a second plasticizer. The first plasticizer comprises 1,3-butanediol, whose molecular structure has two hydroxyl groups located at the 1 and 3 carbon atoms with matched hydroxyl spacing. These hydroxyl groups can form a continuous three-dimensional network association structure through multi-site hydrogen bonds, thereby imparting low surface tension and excellent binder compatibility. This effectively maintains the flexibility of the electrode sheet and inhibits cracking caused by internal stress during the final drying stage. Furthermore, addressing the non-volatility defect of the tight hydrogen bond network of 1,3-butanediol, a second plasticizer is added to the composite plasticizer, comprising a monohydric alcohol and / or an ortho-diol. The monohydric alcohol can compete with 1,3-butanediol for hydrogen bonds through a single hydroxyl group, breaking its continuous association structure. The ortho-diol, with its hydroxyl groups located at adjacent carbon atoms, preferentially forms intramolecular hydrogen bonds or short-range intermolecular hydrogen bonds, hindering the long-range hydrogen bond network of 1,3-butanediol through steric hindrance. This synergistic effect significantly reduces the hydrogen bond association degree of the composite plasticizer system, weakens the intermolecular forces of 1,3-butanediol, thereby improving the volatilization efficiency of the composite plasticizer under drying conditions and greatly reducing the residual amount in the electrode sheet. At the same time, in the early stage of drying of the electrode sheet, the second plasticizer, as an organic solvent, can also reduce the surface tension of the electrode slurry and inhibit cracking. Ultimately, while ensuring the plasticizing effect, it improves the yield of electrode sheets under thick coating and high coating speed.
[0007] In some embodiments, the boiling point of the second plasticizer is 167~207°C under standard atmospheric pressure.
[0008] In some embodiments, the water solubility of the second plasticizer at 25 °C is greater than or equal to 2.5 g / 100 mL.
[0009] In some embodiments, the second plasticizer accounts for 10-50% of the total mass of the composite plasticizer.
[0010] In some embodiments, the second plasticizer accounts for 20-40% of the total mass of the composite plasticizer.
[0011] In some embodiments, the second plasticizer includes at least one of 1,2-butanediol, 2,3-butanediol, 1,2-propanediol, 1,2-pentanediol, 1,2-cyclopentanediol, benzyl alcohol, isononol, 2-propylheptanol, and 2-ethylhexanol.
[0012] In some embodiments, the boiling point of the second plasticizer is lower than that of the first plasticizer.
[0013] A second aspect of this application provides an electrode paste comprising the composite plasticizer described above.
[0014] In some embodiments, the electrode paste further includes: an active material, a conductive agent, and a binder.
[0015] A third aspect of this application provides the use of a composite plasticizer in the preparation of electrode sheets, wherein the composite plasticizer is as described above.
[0016] A fourth aspect of this application provides an electrode sheet comprising the composite plasticizer as described above, or the electrode paste as described above.
[0017] The fifth aspect of this application provides a battery comprising the composite plasticizer as described above, or the electrode slurry as described above, or the electrode sheet as described above.
[0018] The sixth aspect of this application provides an electrical device comprising the composite plasticizer as described above, or the electrode paste as described above, or the electrode sheet as described above, or the battery as described above. Attached Figure Description
[0019] Figure 1 This is a schematic diagram illustrating the preparation of a composite plasticizer according to an embodiment of this application; Figure 2 This is a gas-liquid equilibrium phase diagram of a composite plasticizer according to an embodiment of this application. Figure 3 This is a schematic diagram of a battery according to an embodiment of this application; Figure 4 This is a schematic diagram of an energy storage device according to an embodiment of this application; Figure 5 This is a schematic diagram of an embodiment of the power supply system of this application. Detailed Implementation
[0020] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the composite plasticizer, electrode paste, and their uses. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of essentially identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.
[0021] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values of 1 and 2 are listed, and if maximum range values of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
[0022] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.
[0023] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.
[0024] In conventional technologies, plasticizers are typically introduced during the electrode slurry mixing process to improve electrode flexibility and address defects such as microcracks and powder shedding on the electrode surface. 1,3-Butanediol is widely used as a negative electrode plasticizer due to its good compatibility with water-based binders such as carboxymethyl cellulose (CMC) and its ability to effectively reduce surface tension at the liquid-gas interface during the drying process, significantly suppressing microcrack formation. However, the presence of two hydroxyl groups at the 1 and 3 positions in the 1,3-butanediol molecular structure facilitates the formation of stable intermolecular association networks through hydrogen bonding, making it difficult to completely volatilize under conventional baking conditions. The 1,3-butanediol remaining in the electrode not only consumes electrolyte and affects the stable formation of the solid electrolyte interphase (SEI) film, but may also trigger side reactions, leading to increased battery impedance, decreased rate performance, and reduced cycle life, severely restricting the performance of high-energy-density, long-life lithium-ion batteries.
[0025] To address these issues, traditional technologies have attempted improvements from different angles. One approach involves using polymeric residual plasticizers, synthesizing polymeric plasticizers that can stably exist within the battery cell through molecular design, thus avoiding side reactions caused by small molecule residues. However, these polymeric plasticizers themselves lack electrochemical activity; their long-term presence in the negative electrode occupies effective space, reducing the mass ratio of active materials and directly leading to a decrease in battery energy density, contradicting the development trend of high-energy-density batteries. Another approach uses lithium-ion battery electrolyte components as plasticizers, such as carbonate solvents (ethylene carbonate EC, dimethyl carbonate DMC, etc.). The advantage is that even if trace amounts remain, they will not introduce impurities from the non-electrolyte system, avoiding negative impacts on battery electrochemical performance. However, this approach suffers from significant process compatibility defects: taking ethylene carbonate (EC) as an example, its melting point is approximately 36°C. During normal temperature pipeline transportation, it is highly susceptible to crystallization due to temperature fluctuations, leading to blockages in the supply pipeline and pump jamming, severely affecting the continuous and automated operation of the coating production line and failing to meet the process stability requirements of large-scale mass production.
[0026] In summary, traditional technologies still face a technical bottleneck in addressing the cracking problem of negative electrodes under thick coatings and high coating speeds: the difficulty in simultaneously achieving a balance between crack prevention capability, plasticizer volatility, battery energy density, and process mass production feasibility. There is an urgent need to develop a novel plasticizer that can effectively inhibit coating cracking during the drying process, efficiently volatilize during the baking stage without leaving residue, without sacrificing battery energy density, and is highly compatible with existing aqueous coating processes to meet the demands of large-scale, high-yield, and highly consistent production.
[0027] Based on this, this application proposes a composite plasticizer for use in electrode pastes, comprising a first plasticizer and a second plasticizer. The first plasticizer comprises 1,3-butanediol, whose molecular structure has two hydroxyl groups located at the 1 and 3 carbon atoms, with matched hydroxyl spacing. This allows for the formation of a continuous three-dimensional network association structure through multi-site hydrogen bonds, resulting in low surface tension and excellent binder compatibility. During the final drying stage of the electrode sheet, it effectively maintains the flexibility of the sheet and inhibits cracking caused by internal stress in the adhesive film. Furthermore, addressing the non-volatility defect of the tight hydrogen bond network of 1,3-butanediol, a second plasticizer is added to the composite plasticizer, comprising a monohydric alcohol and / or an ortho-diol. The monohydric alcohol can compete with 1,3-butanediol for hydrogen bonds through a single hydroxyl group, disrupting its continuous association structure. The ortho-diol, with its hydroxyl groups located on adjacent carbon atoms, preferentially forms intramolecular hydrogen bonds or short-range intermolecular hydrogen bonds, hindering the long-range hydrogen bond network of 1,3-butanediol through steric hindrance. This synergistic effect significantly reduces the hydrogen bond association degree of the composite plasticizer system, weakens the intermolecular forces of 1,3-butanediol, thereby improving the volatilization efficiency of the composite plasticizer under drying conditions and greatly reducing the residual amount in the electrode sheet. At the same time, in the early stage of drying of the electrode sheet, the second plasticizer, as an organic solvent, can also reduce the surface tension of the electrode slurry and inhibit cracking. Ultimately, while ensuring the plasticizing effect, it improves the yield of electrode sheets under thick coating and high coating speed.
[0028] The first aspect of this application provides a composite plasticizer for use in electrode paste, comprising: a first plasticizer and a second plasticizer; wherein the first plasticizer comprises: 1,3-butanediol; and the second plasticizer comprises: at least one of a monohydric alcohol and an ortho-diol.
[0029] Alternatively, the monohydric alcohol has a monohydroxy structure.
[0030] Optionally, a hydroxyl group is attached to each of the two adjacent carbon atoms of the ortho-diol.
[0031] Optionally, refer to Figure 1 (a) Corresponding to the associated state of 1,3-butanediol, multiple molecules are connected together by dashed lines (hydrogen bonds), forming an infinitely extending network structure. This structure results in extremely strong intermolecular forces and a high boiling point (1,3-butanediol boiling point is approximately 207℃). During the baking of the electrode paste, it is difficult to overcome this attraction and escape, leading to excessive residue. However, due to its molecular structure, 1,3-butanediol possesses low surface tension and excellent binder compatibility, effectively maintaining the flexibility of the electrode sheet and inhibiting cracking caused by internal stress in the adhesive film during the final stage of electrode drying.
[0032] Optionally, refer to Figure 1(b) Corresponding to the system state of the composite plasticizer with added ortho-diol, it can be seen that the molecules form closed cyclic structures or very small clusters. Due to their spatial advantages, they tend to form intramolecular hydrogen bonds or stable cyclic dimers. When it is mixed with 1,3-butanediol, it can disrupt... Figure 1 (a) The infinitely long chains force the system to become individual molecular clusters, which makes it easier to volatilize.
[0033] Optionally, refer to Figure 1 (c) Corresponding to the system state of the composite plasticizer with added monohydric alcohol, it can be seen that... Figure 1 In (a), the originally continuous chain is cut off, and the ends are free or connected to different molecules. This is because the hydroxyl group of the monohydroxy alcohol is inserted in the middle of the long chain of 1,3-butanediol, forcibly terminating the chain growth. This makes it impossible for 1,3-butanediol to form a tight hydrogen bond network, and the intermolecular binding is greatly weakened, thereby improving the volatilization efficiency of the composite plasticizer under drying conditions and greatly reducing the amount of residue in the electrode sheet.
[0034] In one feasible embodiment, the second plasticizer comprises at least one of 1,2-butanediol, 2,3-butanediol, 1,2-propanediol, 1,2-pentanediol, 1,2-cyclopentanediol, benzyl alcohol, isononol, 2-propylheptanol, and 2-ethylhexanol.
[0035] In this embodiment, a composite plasticizer is provided for use in electrode paste, comprising a first plasticizer and a second plasticizer. The first plasticizer comprises 1,3-butanediol, whose molecular structure has two hydroxyl groups located at the 1 and 3 carbon atoms, with matched hydroxyl spacing. This allows for the formation of a continuous three-dimensional network association structure through multi-site hydrogen bonds, resulting in low surface tension and excellent binder compatibility. This effectively maintains the flexibility of the electrode sheet and inhibits cracking caused by internal stress during the final drying stage. Furthermore, addressing the non-volatility defect of the tight hydrogen bond network of 1,3-butanediol, a second plasticizer is added to the composite plasticizer, comprising a monohydric alcohol and / or an ortho-diol. The monohydric alcohol can compete with 1,3-butanediol for hydrogen bonds through a single hydroxyl group, disrupting its continuous association structure. The ortho-diol, with its hydroxyl groups located on adjacent carbon atoms, preferentially forms intramolecular hydrogen bonds or short-range intermolecular hydrogen bonds, hindering the long-range hydrogen bond network of 1,3-butanediol through steric hindrance. This synergistic effect significantly reduces the hydrogen bond association degree of the composite plasticizer system, weakens the intermolecular forces of 1,3-butanediol, thereby improving the volatilization efficiency of the composite plasticizer under drying conditions and greatly reducing the residual amount in the electrode sheet. At the same time, in the early stage of drying of the electrode sheet, the second plasticizer, as an organic solvent, can also reduce the surface tension of the electrode slurry and inhibit cracking. Ultimately, while ensuring the plasticizing effect, it improves the yield of electrode sheets under thick coating and high coating speed.
[0036] Optionally, the boiling point of the second plasticizer is lower than that of the first plasticizer.
[0037] In one feasible embodiment, the boiling point of the second plasticizer is 167~207℃ at standard atmospheric pressure (101.325 kPa). For example, the boiling points of the second plasticizer are 167℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 207℃, etc.
[0038] In this embodiment, the boiling point of the second plasticizer is limited to 167~207℃, forming a clever synergistic effect with the volatilization behavior of 1,3-butanediol (the first plasticizer) in the system. During the later stages of drying, as 1,3-butanediol gradually volatilizes, the second plasticizer within this boiling point range, due to its moderate volatility, can effectively increase the saturated vapor pressure of the free plasticizer system while retaining sufficient plasticizing effect. This ensures that the second plasticizer will not escape prematurely in the early stages of drying due to an excessively low boiling point, disrupting slurry leveling, nor will it be difficult to volatilize due to an excessively high boiling point, resulting in residue. This allows the composite plasticizer to maintain a high vapor pressure within a wide temperature range of 60~120℃, thus constructing a mixed system with "generally positive deviation" characteristics together with 1,3-butanediol. This not only significantly reduces the hydrogen bonding degree of the system and optimizes the processing rheological properties, but also ensures that at the end of the electrode slurry drying process, after some 1,3-butanediol has entered the film network and played a permanent plasticizing role, the remaining free plasticizer (rich in this second plasticizer) can still be quickly and completely discharged from the thick-coated electrode due to its excellent volatility. This solves the defects such as blistering and pinholes caused by plasticizer residue under high coating speeds and greatly improves the electrode yield.
[0039] In one feasible embodiment, at 25 °C, the water solubility of the second plasticizer (i.e., its solubility in deionized water) is greater than or equal to 2.5 g / 100 mL.
[0040] In this embodiment, during the electrode drying process, the second plasticizer can be released first through thermal evaporation due to its moderate boiling point. For the residual parts deep in the coating or those that are difficult to completely evaporate due to the thick coating process, it has high water solubility (≥2.5 g / 100 mL). This ensures that it can be quickly dissolved and carried away by the solvent components in the electrolyte during the subsequent liquid injection or wetting process, thereby avoiding electrode swelling, increased interfacial impedance or electrochemical performance degradation caused by plasticizer residue.
[0041] In one feasible embodiment, the second plasticizer accounts for 10-50% of the total mass of the composite plasticizer. For example, the second plasticizer accounts for 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% of the total mass of the composite plasticizer.
[0042] In one feasible embodiment, the mass of the second plasticizer accounts for 20-40% of the total mass of the composite plasticizer.
[0043] Optionally, the gas-liquid equilibrium phase diagram of the composite plasticizer is referenced. Figure 2 The composite plasticizer system includes: component A (i.e., the first plasticizer) and component B (i.e., the second plasticizer). Figure 2 The horizontal axis represents the composition ratio of the second plasticizer (component B) to the first plasticizer (component A) in the composite plasticizer, and the vertical axis represents the temperature. Figure 2 The lower curve represents the liquidus line, and the upper curve represents the vapor line. In an ideal solution, the boiling point of the mixture typically lies between the boiling points of the two pure components. The composite plasticizer in this application belongs to a "general positive deviation system," such as... Figure 2 As shown, its gas-liquid equilibrium curve exhibits obvious nonlinear characteristics. Because the interaction force (hydrogen bond association degree) between the second plasticizer (component B) and the first plasticizer (component A) molecules is weaker than the interaction force between molecules of the same type, the molecules of the mixed system are more likely to escape into the gas phase. Figure 2 The curve morphology shows that, over a wide range of compositional ratios, the bubble point temperature (the temperature at which boiling begins) of the mixed system is significantly lower than the theoretical value under ideal mixing conditions. This means that at the same drying temperature, the saturated vapor pressure of this system is higher than that of an ideal solution, thus maintaining a high vapor pressure. As the proportion of the second plasticizer (component B) increases, the liquidus curve of the system generally shows a downward trend. This implies that during the drying process, as the volatile first plasticizer (component A) gradually decreases, the concentration of the second plasticizer (component B) in the remaining liquid phase becomes relatively concentrated. Due to the positive deviation characteristic of this system, the remaining mixture enriched with the second plasticizer is not as difficult to volatilize as traditional high-boiling-point solvents. Instead, due to its lower boiling point and the high vapor pressure effect brought about by the positive deviation, it can continue to volatilize rapidly at a lower boiling temperature. In other words, as drying progresses, the difficulty of volatilizing the remaining liquid does not increase significantly. Instead, due to the presence of the second plasticizer and the positive deviation effect, it maintains high volatility, thus ensuring that the composite plasticizer can still quickly and fully volatilize from the electrode in the later stages of drying, reducing plasticizer residue.
[0044] In this embodiment, adding an appropriate amount of a second plasticizer to the composite plasticizer can fully leverage its synergistic properties of moderate boiling point and good water solubility. On the one hand, during the drying stage, the second plasticizer can form a positive deviation system with 1,3-butanediol, increasing the saturated vapor pressure and ensuring rapid volatilization under thick coating and high coating speed, while retaining sufficient plasticizing effect to inhibit electrode cracking. On the other hand, the high water solubility of the second plasticizer can dissolve residual parts, avoiding electrolyte side reactions. If the amount of the second plasticizer added to the composite plasticizer is too low, it is difficult to form an effective positive deviation system, resulting in insufficient volatilization efficiency and easy to lead to electrode residue and interface defects. If the amount of the second plasticizer added to the composite plasticizer is too high, although the volatilization rate is increased, it may affect the coating uniformity due to excessive reduction of slurry viscosity, and excessive residue will cause electrolyte component imbalance due to excessive water solubility, increasing interfacial impedance and even triggering side reactions. Therefore, in this embodiment, the mass of the second plasticizer is determined to be 10-50% of the total mass of the composite plasticizer.
[0045] A second aspect of this application provides an electrode paste. The electrode paste includes the composite plasticizer provided in the first aspect of this application. The function of the electrode paste of the second aspect of this application can be referred to the function of the composite plasticizer provided in the first aspect of this application. Other technical features of this electrode paste are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.
[0046] Optionally, the electrode paste includes: active material, conductive agent, binder, and composite plasticizer.
[0047] Optionally, the electrode slurry may also include a solvent.
[0048] Optionally, the active material includes: positive electrode active material and negative electrode active material.
[0049] Optionally, the electrode slurry includes: positive electrode slurry and negative electrode slurry.
[0050] A third aspect of this application provides the use of a composite plasticizer in the preparation of electrode sheets, wherein the composite plasticizer is the same as that provided in the first aspect of this application. The technical effects of the use in this third aspect are the same as those of the composite plasticizer provided in the first aspect of this application. Other technical features in this use are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.
[0051] Optionally, the composite plasticizer can be added to the electrode slurry. During the preparation of the electrode sheet, the electrode slurry can be coated onto at least one surface of the current collector to form a wet coating. The current collector can be a metal foil, for example, aluminum foil for the positive electrode and copper foil for the negative electrode. The current collector coated with the electrode slurry is then placed in an oven for drying. During the drying process, the composite plasticizer is gradually heated and evaporated along with the solvent in the electrode slurry. As the solvent and composite plasticizer evaporate, the electrode active material, conductive agent, and binder in the electrode slurry gradually form a solid film with a porous network structure on the surface of the current collector. This film is the active material layer (also called the coating layer) of the electrode sheet. Since the composite plasticizer is almost completely removed during the drying process, the residual amount of composite plasticizer in the final coating layer of the electrode sheet is extremely low.
[0052] This application provides a fourth aspect of an electrode sheet. The electrode sheet includes the composite plasticizer provided in the first aspect of this application, or the electrode slurry provided in the second aspect of this application. The electrode sheet of this third aspect functions similarly to the composite plasticizer provided in the first aspect of this application. Other technical features of the electrode slurry are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.
[0053] Optionally, the electrode plates include: a positive electrode plate and a negative electrode plate.
[0054] Optionally, by coating the electrode paste onto a current collector (e.g., aluminum foil, copper foil), and drying it to remove the solvent, an electrode sheet is formed. The composite plasticizer is also gradually heated and evaporated along with the solvent in the electrode paste, resulting in extremely low residual amount of composite plasticizer in the final coating layer of the electrode sheet.
[0055] Optionally, the active material layer (i.e., dressing layer) of the electrode sheet contains the composite plasticizer provided in the first aspect of this application.
[0056] This application provides a battery in a fifth aspect. The battery includes the composite plasticizer provided in the first aspect of this application, the electrode slurry provided in the second aspect of this application, or the electrode sheet provided in the third aspect of this application. The battery of this fourth aspect functions similarly to the composite plasticizer provided in the first aspect of this application. Other technical features of this battery are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.
[0057] In addition, the battery and power-consuming device of this application will be described below with appropriate reference to the accompanying drawings.
[0058] In one embodiment of this application, a battery is provided.
[0059] Typically, a battery consists of a positive electrode, a negative electrode, an electrolyte, and a separator. During charging and discharging, active ions move back and forth between the positive and negative electrodes, inserting and releasing. The electrolyte acts as a conductor between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing ions to pass through.
[0060] Positive electrode sheet The positive electrode sheet may include a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector.
[0061] Optionally, the positive electrode active material layer includes the composite plasticizer provided in the first aspect of this application.
[0062] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.
[0063] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
[0064] In some embodiments, the positive electrode active material layer may further include a binder. As an example, the binder may include at least one selected from polyvinylidene fluoride, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, and carboxymethyl chitosan.
[0065] In some embodiments, the positive electrode active material layer may further include a conductive agent. As an example, the conductive agent may include at least one of acetylene black, superconducting carbon, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
[0066] Negative electrode sheet The negative electrode sheet may include only a negative current collector, or it may include a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector, wherein the negative active material layer includes a negative active material.
[0067] Optionally, the negative electrode active material layer includes the composite plasticizer provided in the first aspect of this application.
[0068] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.
[0069] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
[0070] In some embodiments, the negative electrode active material may be a negative electrode active material known in the art. As an example, the negative electrode active material may include at least one of: artificial graphite, natural graphite, soft carbon, hard carbon, and silicon-based materials. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.
[0071] electrolytes The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific restrictions on the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel, or entirely solid.
[0072] Separating membrane In some embodiments, the battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.
[0073] In some embodiments, the material of the separator can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.
[0074] In some embodiments, the battery may include an outer packaging. This outer packaging may be used to encapsulate the electrode assembly and electrolyte described above.
[0075] In some implementations, the battery's outer packaging can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The battery's outer packaging can also be a soft pack, such as a pouch. The soft pack can be made of plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.
[0076] This application does not impose any particular limitation on the shape of the battery; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 3 This is a square-shaped battery as an example.
[0077] In addition, this application also provides an electrical device, which includes at least one of the composite plasticizer, electrode slurry, electrode sheet, and battery provided in this application. The battery can be used as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
[0078] As an electrical device, the battery can be selected according to its usage requirements.
[0079] Optionally, refer to Figure 4 The electrical device can be an energy storage device. The energy storage device can adopt an integrated structure of cabinet or container and can be deployed independently outdoors or indoors as a backup power source or peak shaving and frequency regulation equipment.
[0080] Optionally, refer to Figure 5 The electrical device can be applied to an electrical system that can integrate new energy power generation equipment (such as wind turbines and photovoltaic modules), the electrical device (i.e., energy storage device) of the present application embodiment, and the load.
[0081] As an example, the electrical device can be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of the battery for this electrical device, a battery pack or battery module can be used.
[0082] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can be powered by a battery.
[0083] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.
[0084] Example 1 By weight, 96 parts of graphite anode active material, 1 part of conductive carbon black, 2 parts of SBR binder, 1 part of CMC dispersant, and 100 parts of deionized water were mixed, and 1.5 parts of composite plasticizer were added, wherein the composite plasticizer included 1.0 part of 1,3-butanediol and 0.5 parts of S,S-2,3-butanediol; the mixture was stirred evenly to obtain anode slurry. The slurry was coated onto the surface of copper foil, and after drying, anode sheet was obtained. The coating speed was 15 m / min, the drying temperature was 80 ℃, and the air frequency was 16.
[0085] Example 2 The difference from Example 1 is that the second plasticizer is replaced with isononol.
[0086] Example 3 The difference from Example 1 is that the composite plasticizer includes 1.35 parts of 1,3-butanediol and 0.15 parts of S,S-2,3-butanediol.
[0087] Example 4: The difference from Example 1 is that the composite plasticizer includes 0.75 parts of 1,3-butanediol and 0.75 parts of S,S-2,3-butanediol.
[0088] Comparative Example 1 The difference from Example 1 is that only 1.5 parts of 1,3-butanediol, a single plasticizer, were added.
[0089] Comparative Example 2 The difference from Example 1 is that the second plasticizer is replaced with 1,4-butanediol (i.e., non-ortho-diol).
[0090] Comparative Example 3 The difference from Example 1 is that the second plasticizer is replaced with cyclopentanol, which has a boiling point of 141 °C.
[0091] Comparative Example 4 The difference from Example 1 is that the second plasticizer is replaced with 2-ethylhexanol, which has a water solubility of 1g / 100ml.
[0092] Comparative Example 5 The difference from Example 1 is that the composite plasticizer includes 1.425 parts of 1,3-butanediol and 0.075 parts of S,S-2,3-butanediol.
[0093] Comparative Example 6 The difference from Example 1 is that the composite plasticizer includes 0.6 parts of 1,3-butanediol and 0.9 parts of S,S-2,3-butanediol.
[0094] The appearance and plasticizer residue of each negative electrode sheet of Examples 1-4 and Comparative Examples 1-6 were tested. Based on the above negative electrode sheets, battery cells were prepared, and the energy efficiency at 25°C and 0.5 P was tested. The results are shown in Table 1 below: Table 1
[0095] Based on the above experimental results, it can be seen that the embodiments of this application can effectively avoid cracking of the negative electrode sheet after drying. Compared with comparative examples 1-3 and 5, it can be seen that by introducing a second plasticizer with a specific molecular configuration and controlling the amount of the second plasticizer added, the embodiments 1-4 of this application effectively inhibit the formation of the hydrogen bond network between 1,3-butanediol molecules, improve the volatilization efficiency of the mixed plasticizer during the drying process, and significantly reduce the residue of plasticizer in the negative electrode sheet while ensuring the yield of the thick electrode and high coating speed process. At the same time, it improves the dynamic performance and long-term cycle reliability of the battery cell.
[0096] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.
Claims
1. A composite plasticizer, characterized in that, The material is applied to electrode pastes and includes: a first plasticizer and a second plasticizer; wherein the first plasticizer includes: 1,3-butanediol; and the second plasticizer includes: at least one of a monohydric alcohol and an ortho-diol.
2. The composite plasticizer as described in claim 1, characterized in that, Under standard atmospheric pressure, the boiling point of the second plasticizer is 167~207℃.
3. The composite plasticizer as described in claim 1, characterized in that, At 25 °C, the water solubility of the second plasticizer is greater than or equal to 2.5 g / 100 mL.
4. The composite plasticizer as described in claim 1, characterized in that, The second plasticizer accounts for 10-50% of the total mass of the composite plasticizer.
5. The composite plasticizer as described in claim 4, characterized in that, The second plasticizer accounts for 20-40% of the total mass of the composite plasticizer.
6. The composite plasticizer as described in claim 1, characterized in that, The second plasticizer includes at least one of 1,2-butanediol, 2,3-butanediol, 1,2-propanediol, 1,2-pentanediol, 1,2-cyclopentanediol, benzyl alcohol, isononol, 2-propylheptanol, and 2-ethylhexanol.
7. The composite plasticizer as described in claim 1, characterized in that, The boiling point of the second plasticizer is lower than that of the first plasticizer.
8. An electrode paste, characterized in that, Includes the composite plasticizer as described in any one of claims 1 to 7.
9. The electrode paste as described in claim 8, characterized in that, The electrode paste also includes: active materials, conductive agents, and binders.
10. The use of a composite plasticizer in the preparation of electrode sheets, characterized in that, The composite plasticizer is the composite plasticizer as described in any one of claims 1 to 7.