An in-situ solid-state battery and a method of manufacturing the same

Abstract

The embodiment of the present application provides a kind of in situ solid-state battery and preparation method thereof, belong to battery technical field.The preparation method includes: in situ solidification electrolyte precursor is injected into battery, and the battery to be solidified is obtained;And pulse current is applied to the electrode of the battery to be solidified, to heat solidification is carried out to the in situ solidification electrolyte precursor, and solid-state battery is obtained.The embodiment of the present application adopts pulse heating solidification mode, utilizes the self impedance of battery interior to realize solidification heating, and heating mode is more uniform, relatively makes the polymerization effect also more uniform, to make battery interface more uniform and stable.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically to an in-situ solid-state battery and its preparation method. Background Technology

[0002] The dwindling supply of fossil resources and increasing environmental pollution have made green, efficient, and clean new electrochemical energy storage devices the preferred choice. To achieve large-scale adoption of electric vehicles, improving the energy density and safety of power batteries has become the most important research direction internationally. Increasing battery energy density not only increases driving range but also reduces cell costs and extends battery life.

[0003] However, with the increase in the energy density of lithium batteries, battery safety has become a major concern. Currently, lithium batteries primarily use liquid electrolytes, but liquid organic electrolytes pose safety risks such as volatility, leakage, and flammability. To address this issue, researchers have proposed replacing traditional liquid electrolytes with polymer electrolytes, which can effectively mitigate the safety risks associated with liquid organic electrolytes and reduce the likelihood of battery explosions.

[0004] Currently, the preparation process of polymer electrolytes has abandoned the complex steps of polymer dissolution, drying for film formation, and electrolyte swelling, and has instead adopted an in-situ polymerization method to generate polymer electrolytes. This method gives polymer lithium batteries better interfacial compatibility, significantly improves battery performance, effectively reduces costs, and is well compatible with existing battery industrial systems, showing promising application prospects.

[0005] However, this involves in-situ curing initiation processes for electrolytes, which are mainly divided into UV initiation, electrochemical initiation, and thermal initiation. Currently, UV curing is fast and has high initiation efficiency, but because the inside of the battery cell is opaque, UV light cannot be used for cell curing. Electrochemical initiation in-situ curing processes have specific requirements for monomers and initiators, exhibiting strong selectivity, and the curing process is prone to uneven monomer polymerization reactions. In addition, the polymerization products of electrochemical initiation coat the electrode surface, and the polymerization products usually have poor conductivity, causing subsequent monomers to be unable to gain or lose electrons, leading to the termination of the polymerization reaction. Thermal initiation polymerization is a commonly used in-situ curing method, which mainly uses heat conduction to heat the battery for curing. However, in the curing process of thermal initiation polymerization, the outer electrode of the battery cell is heated first, and then the heat is conducted step by step to the inner electrode of the battery cell, resulting in uneven thermal field distribution inside the battery cell. Moreover, the oven used for heating itself also has the problem of uneven temperature. These combined factors make thermal initiation prone to uneven curing problems; in addition, this method has problems such as long time consumption, high energy consumption, and high cost. Therefore, there is an urgent need to develop a process for in-situ solidification of electrolytes that can at least partially solve the above problems. Summary of the Invention

[0006] This invention provides an in-situ solid-state battery and its preparation method. By setting reasonable pulse current parameters to heat the battery cell containing the in-situ solidified electrolyte precursor, the internal resistance of the battery cell is used to make the internal electrode sheets of the battery cell uniformly heated, thereby achieving in-situ uniform polymerization of the battery cell. At the same time, the polymerization time can be significantly shortened and energy consumption reduced.

[0007] To achieve the above objectives, embodiments of the present invention provide a method for preparing an in-situ solid-state battery, comprising: injecting an in-situ solidified electrolyte precursor into a battery cell to obtain a battery to be solidified; and applying a pulsed current to the electrodes of the battery to be solidified to heat and solidify the in-situ solidified electrolyte precursor to obtain a solid-state battery.

[0008] Optionally, the waveform of the pulse current is an alternating sine wave; the frequency of the pulse current is 0.1Hz-100kHz, preferably 5Hz-1000Hz, more preferably 10Hz-20Hz; the amplitude of the pulse current is 0.5C-5C, preferably 1C-3C; and the total application time of the pulse current is 5-60min, preferably 20min-30min.

[0009] Optionally, the waveform of the pulse current is a DC-AC sine wave; the frequency of the pulse current is 0.1Hz-100kHz, preferably 5Hz-1000Hz, more preferably 10Hz-20Hz; the amplitude of the AC current and the DC battery in the pulse current is 0.5C-5C, preferably 1C-3C; and the total application time of the pulse current is 5-60min, preferably 20-30min, wherein the DC current and AC current in the DC-AC sine wave are applied simultaneously, preferably the DC current is applied only once in every 900s total application time, and each application lasts 10s-20s, preferably 10s.

[0010] Optionally, the waveform of the pulse current is a DC-AC sine wave; the frequency of the pulse current is 0.1Hz-100kHz, preferably 5Hz-1000Hz, more preferably 10Hz-20Hz; the amplitude of the AC current and the DC battery in the pulse current is 0.5C-5C, preferably 1C-3C; and the total application time of the pulse current is 5-60min, preferably 20-30min, wherein the DC current and AC current in the DC-AC sine wave are applied alternately, preferably the DC current is applied only once in every 900s total application time, and each application lasts 10s-20s, preferably 10s.

[0011] Optionally, the waveform of the pulse current is any one of AC triangular wave, AC square wave, and AC sawtooth wave; the frequency of the pulse current is 0.1Hz-100kHz, preferably 5Hz-1000Hz, more preferably 10Hz-20Hz; the amplitude of the pulse current is 0.5C-5C, preferably 1C-3C; and the total application time of the pulse current is 5-60min, preferably 20min-30min.

[0012] Optionally, before injecting the in-situ cured electrolyte precursor into the battery cell, the preparation method further includes: mixing polymer monomers, initiators, organic solvents, lithium salts and additives to obtain the in-situ cured electrolyte precursor.

[0013] Optionally, the polymer monomer is selected from any one of the following: monomers containing unsaturated carbon-carbon double bonds; cyclic monomers that can be ring-opened polymerized; and monomers containing polymerizable active functional groups.

[0014] Optionally, the initiator is selected from any one of the following: azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl, diisopropylbenzene peroxide, dibenzoyl peroxide, and ammonium persulfate.

[0015] Optionally, applying a pulse current to the electrodes of the battery to be cured includes: adapting and connecting the positive and negative electrodes of the battery to be cured to the positive and negative electrodes of the pulse charging and discharging device; and controlling the pulse charging and discharging device to deliver a pulse current to the battery to be cured by adjusting the pulse parameters of the pulse charging and discharging device.

[0016] This invention also provides an in-situ solid-state battery, which is prepared by any of the preparation methods described above.

[0017] Optionally, the in-situ solid-state battery is any one of a lithium-ion battery, a magnesium-ion battery, a zinc-ion battery, and an aluminum-ion battery.

[0018] Through the above technical solution, the embodiments of the present invention adopt a pulse heating curing method, which utilizes the internal impedance of the battery to achieve curing heating. The heating method is more uniform, which makes the polymerization effect more uniform, thereby making the battery interface more uniform and stable.

[0019] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0021] Figure 1 Figure 2 is a schematic flowchart of the in-situ solid-state battery preparation method of the present invention; and Figures 2(a) and 2(b) are photographs of the battery interfaces of Example 1 and Comparative Example 1, respectively. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0023] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] like Figure 1 As shown, the first aspect of the present invention provides a method for preparing an in-situ solid-state battery, which may include the following steps:

[0025] Step S1: Inject the in-situ cured electrolyte precursor into the cell to obtain the battery to be cured;

[0026] Step S2: Apply a pulsed current to the electrodes of the battery to be cured to heat and cure the in-situ cured electrolyte precursor, thereby obtaining a solid-state battery.

[0027] This in-situ solid-state battery fabrication method utilizes the battery's equivalent internal resistance to generate heat during charging and discharging, achieving a self-heating effect. Furthermore, addressing the issue of uneven thermal field distribution within the cell caused by heat sources such as ovens in thermal polymerization methods, it employs pulse charging and discharging for heating. This allows the internal electrodes to be heated simultaneously, ensuring that all electrodes within the battery maintain an isothermal temperature field at any given time. This prevents battery aging as the temperature gradually increases. Therefore, this invention aims to induce uniform in-situ solidification of the battery through pulse charging and discharging without affecting battery performance.

[0028] For step S1, the polymer monomer, initiator, organic solvent, lithium salt and additives are mixed in, for example, a glove box to obtain the in-situ cured electrolyte precursor.

[0029] Preferably, the polymer monomer is selected from thermally initiated polymer electrolyte monomers or thermally initiated gel electrolyte monomers, more preferably from any one of the following: monomers containing unsaturated carbon-carbon double bonds; cyclic monomers capable of ring-opening polymerization; and monomers containing polymerizable active functional groups. For example, monomers containing unsaturated carbon-carbon double bonds can be used to generate thermally initiated gel electrolyte monomers.

[0030] Preferably, the initiator may be selected from any one of the following: azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl, diisopropylbenzene peroxide, dibenzoyl peroxide, and ammonium persulfate.

[0031] For step S2, applying a pulse current to the electrodes of the battery to be cured may include: adapting and connecting the positive and negative electrodes of the battery to be cured to the positive and negative electrodes of the pulse charging and discharging device; and controlling the pulse charging and discharging device to deliver a pulse current to the battery to be cured by adjusting the pulse parameters of the pulse charging and discharging device.

[0032] For example, a pulse charge / discharge device is a pulse power supply, whose pulse parameters include any one or more of the following: pulse waveform, pulse frequency, pulse current amplitude, pulse time, and upper and lower limit voltages. The upper and lower limit voltages are configured to match the upper and lower limit voltages of the battery during operation, and will not be elaborated further here. The other parameters can be understood with reference to the following text.

[0033] The pulse waveform can be any one of AC sine wave, AC triangular wave, AC square wave, AC sawtooth wave, and DC-AC sine wave.

[0034] In a preferred embodiment, the waveform of the pulsed current is an alternating sine wave; the frequency of the pulsed current is 0.1Hz-100kHz, preferably 5Hz-1000Hz, more preferably 10Hz-20Hz; the amplitude of the pulsed current is 0.5C-5C, preferably 1C-3C; and the total application time of the pulsed current is 5-60min, preferably 20min-30min. Here, the current amplitude refers to the maximum value that the current fluctuation can reach; for example, if the alternating current range is -2C to 2C, then its amplitude is 2C. The relationship between the current unit (A) and the amplitude unit (C) is described by the following formula:

[0035] Current A = Battery capacity Ah * Rate C (h) -1 ).

[0036] In another preferred embodiment, the waveform of the pulsed current is a DC-AC sine wave. For this DC-AC sine wave: the current frequency is 0.1Hz-100kHz, preferably 5Hz-1000Hz, more preferably 10Hz-20Hz; the current amplitude is 0.5C-5C, preferably 1C-3C; and the total application time of the pulsed current is 5-60 minutes, preferably 20-30 minutes. Further, based on the different application methods of AC and DC currents, the following two preferred cases are also included:

[0037] 1) The DC current and AC current in the DC-AC sine wave are applied simultaneously. Preferably, the DC current is applied only once in a total application time of 900s, and each application lasts for 10s-20s, preferably 10s.

[0038] 2) The DC current and AC current in the DC-AC sine wave are applied alternately. Preferably, the DC current is applied only once in a total application time of 900s, and each application lasts for 10s-20s, preferably 10s.

[0039] In another preferred embodiment, the waveform of the pulse current is any one of an AC triangular wave, an AC square wave, or an AC sawtooth wave; the frequency of the pulse current is 0.1Hz-100kHz, preferably 5Hz-1000Hz, and more preferably 10Hz-20Hz; the amplitude of the pulse current is 0.5C-5C, preferably 1C-3C; and the total application time of the pulse current is 5-60min, preferably 20min-30min.

[0040] A second aspect of the present invention provides an in-situ solid-state battery, which is prepared by the preparation method of the first aspect.

[0041] Preferably, the in-situ solid-state battery is any one of a lithium-ion battery (hereinafter referred to as a lithium battery), a magnesium-ion battery, a zinc-ion battery, and an aluminum-ion battery.

[0042] The in-situ solidification battery and its preparation method of the present invention have the following advantages:

[0043] 1) The pulse heating curing method is adopted, which uses the internal impedance of the battery to generate heat to achieve curing heating. The heating method is more uniform, which makes the polymerization effect more uniform, resulting in a more uniform and stable battery interface.

[0044] 2) By adjusting the pulse waveform, frequency, current amplitude, and pulse application time, uniform heating inside the battery can be achieved without damaging the internal structure of the battery.

[0045] 3) This preparation method is applicable to the in-situ polymerization of most electrolyte precursors;

[0046] 4) The in-situ solid-state battery prepared by this method has a small volume and low cost;

[0047] 5) This preparation method has high heating efficiency and short heating time, which improves production efficiency.

[0048] To further illustrate the advantages of the present invention, more embodiments are described in detail below, but these should not be construed as limiting the scope of protection of the present invention. The raw materials used in the following embodiments of the present invention are all commercially available products.

[0049] (I) Preparation of the battery to be cured.

[0050] Preparation Example 1

[0051] The positive electrode, negative electrode, and separator are sequentially assembled into a cell through stacking, tab welding, top sealing, and side sealing. An in-situ solidified electrolyte precursor is injected into the cell, which is then vacuum-sealed and vacuum-encapsulated to form a battery to be solidified.

[0052] The method for preparing the positive electrode sheet may include: mixing 90-98 wt% of positive active material, 2-4 wt% of conductive agent and 1-5 wt% of binder with solvent based on 100% of the positive electrode sheet mass to obtain a positive electrode slurry; then uniformly coating the slurry on both sides of the positive current collector, and obtaining the desired positive electrode sheet through drying, rolling, slitting and other steps.

[0053] The method for preparing the negative electrode sheet may include: mixing 90-98 wt% of negative electrode active material, 2-4 wt% of conductive agent, and 1-5 wt% of binder with a solvent, based on 100% of the weight of the negative electrode sheet, and stirring until homogeneous to obtain a negative electrode slurry. The slurry is then uniformly coated on both sides of the negative electrode current collector, and subjected to drying, rolling, and slitting steps to obtain the desired negative electrode sheet.

[0054] Taking a lithium-ion battery as an example, the positive electrode active material can be selected from lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, and lithium nickel manganese oxide; the negative electrode active material can be selected from lithium metal, lithium metal alloy, graphite, hard carbon, silicon carbon, tin-based materials, and silicon oxide materials; the separator can be selected from polyolefin separators, ceramic composite separators, cellulose nonwoven membranes, and glass fiber membranes.

[0055] (II) Test methods for in-situ solid-state batteries:

[0056] 1) Polymerization uniformity: Disassemble the cured battery and visually inspect whether the electrode surface is uniform, and evaluate it as poor, average, or good.

[0057] 2) Surface density deviation: Disassemble the cured battery, take the middle positive electrode sheet and divide it into 6 parts with the same area, weigh each of the 6 parts and measure their mass. Surface density deviation = [maximum value max (mass) - minimum value min (mass)] / average value avg (mass).

[0058] 3) The battery cycle life is tested according to the standard cycle life test method in GB / T 31484-2015 "Requirements and Test Methods for Cycle Life of Power Batteries for Electric Vehicles". The capacity retention rate is calculated based on the capacity before and after the cycle.

[0059] 4) The DC internal resistance (DCR) test after battery cycling is conducted according to the hybrid pulse power characteristic test method in DOE / ID-11069 "FreedomCAR Power Assist Battery Test Manual". The increase of DCR after cycling can be known by calculating the DC internal resistance before and after cycling based on R=U / I.

[0060] (III) Preparation and performance of in-situ solid-state batteries:

[0061] Example 1

[0062] In this Example 1, for the battery to be cured in Preparation Example 1, the in-situ solid-state battery preparation method of the present invention is used to prepare the in-situ solid-state battery accordingly.

[0063] (1) For the positive electrode sheet, the preferred configuration of the positive electrode slurry is NCM811, conductive carbon black and polyvinylidene fluoride in a mass ratio of 96:2:2, and the solvent is N-methylpyrrolidone.

[0064] (2) For the negative electrode sheet, the preferred configuration of the negative electrode slurry is artificial graphite, conductive carbon black, styrene-butadiene rubber and sodium carboxymethyl cellulose in a mass ratio of 95:2.5:1.5:1, and the solvent is water.

[0065] (3) The positive electrode, negative electrode, and separator are assembled into a 10Ah ternary NCM / graphite soft-pack lithium battery (i.e., cell) by stacking, welding tabs, top sealing, and side sealing in sequence.

[0066] (4) Prepare the in-situ cured electrolyte precursor: the amount of methyl methacrylate added is, for example, 5g, the amount of azobisisobutyronitrile initiator added is, for example, 0.05g, and the amount of organic solvent added is, for example, 15g.

[0067] (5) Inject the in-situ cured electrolyte precursor prepared in (4) into the assembled 10Ah ternary NCM / graphite soft-pack lithium battery and age it for 24 hours (e.g. at 25°C) to form a battery to be cured (hereinafter also referred to as a lithium battery).

[0068] (6) Connect the positive and negative terminals of the lithium battery after injecting the in-situ solidified electrolyte precursor in (5) to the positive and negative terminals of the pulse charge and discharge device respectively. The pulse wave is an AC sine wave, the voltage range is set to 2.75-4.25V, the AC frequency is 100Hz, the AC current amplitude is 3C, and the total application time of the pulse current (hereinafter referred to as pulse time) is 30min. Finally, the in-situ solid battery is obtained by pulse current solidification.

[0069] (7) Disassemble the original solidified lithium battery and observe the battery interface, as shown in Figure 2(a).

[0070] Comparative Example 1

[0071] (1) Prepare the lithium battery to be cured by referring to steps (1)-(5) of Example 1;

[0072] (2) The lithium battery after injecting the in-situ solidified electrolyte precursor was placed in a 60°C oven and solidified for 24 hours.

[0073] (3) After curing, disassemble the lithium battery and observe the battery interface, as shown in Figure 2(b).

[0074] By comparing Figure 2(a) and Figure 2(b), it can be seen that under the same conditions, the pulsed current curing scheme of Example 1 can obtain a more uniform and stable battery interface compared with the thermally initiated polymerization curing scheme of Comparative Example 1.

[0075] The preferred parameters and advantages of the in-situ solid-state battery preparation method of the present invention are further described below through Examples 2-25 and Comparative Examples 2-5 prepared using the method of Example 1.

[0076] The embodiments involve lithium batteries, aluminum-ion batteries, and sodium-ion batteries, and the materials of the positive electrode, negative electrode, and separator included in their respective cells are shown in Table 1.

[0077] Table 1

[0078] positive electrode negative electrode diaphragm lithium batteries Ternary high-nickel Silicon carbon <![CDATA[PE+Al2O3]]> Aluminum-ion batteries graphite Aluminum <![CDATA[PE+Al2O3]]> Sodium-ion batteries Prussian blue graphite <![CDATA[PE+Al2O3]]>

[0079] The embodiments involve different types of in-situ solidified electrolyte precursors (hereinafter referred to as precursors), and the material composition of each precursor is shown in Table 2.

[0080] Table 2

[0081]

[0082]

[0083] Examples 2-5: Effects of pulse heating with different durations

[0084] Examples 2-5 aim to observe the effect of the total application time of the pulse current on the polymerization effect when the battery is heated and cured by applying an AC sine wave. Examples 2-5 are all based on the lithium battery shown in Table 1 and the first type of precursor shown in Table 2. Step (6) is pulse curing according to the AC sine wave shown in Table 3, and the test results shown in Table 3 are obtained.

[0085] Table 3

[0086]

[0087] Based on the test results shown in Table 3, it is evident that different heating durations in Examples 2-5 can all achieve the heating and curing of lithium batteries. However, Examples 3 and 4 undoubtedly exhibit better polymerization uniformity, smaller areal density deviation, higher capacity retention after 200 cycles at 1C, and smaller DCR increase. Therefore, in the in-situ solid-state battery preparation method of the present invention, when using an AC sine wave pulse waveform, if other pulse parameters remain unchanged, the range of pulse current application time can be 600s-3000s (i.e., 10min-50min) corresponding to Examples 2-5, and more preferably 1200s-1800s (i.e., 20min-30min) corresponding to Examples 3-4. It should be noted that Example 3 is the most preferred embodiment; therefore, in the following comparisons of other examples, the optimal pulse current application time of 1800s determined in Example 3 is used.

[0088] Examples 6-9: Effects of pulse heating with different current amplitudes

[0089] Examples 6-9 aim to observe the effect of the pulse current amplitude on the polymerization effect when an AC sine wave is applied for battery heating and curing. Examples 6-9 are for the lithium battery shown in Table 1 and the first type of precursor shown in Table 2. In step (6), the most preferred total pulse current application time of 1800s determined in Examples 2-5 is used. AC sine waves with different current amplitudes but the same current frequency are applied according to Table 4, and the corresponding test results shown in Table 4 are obtained.

[0090] Table 4

[0091]

[0092] Based on the test results shown in Table 4, it is evident that the heating and curing of the lithium battery can be achieved using the amplitudes in Examples 6-9. However, Examples 7 and 8 undoubtedly exhibit better polymerization uniformity, smaller areal density deviation, higher capacity retention after 200 cycles at 1C, and smaller DCR increase. Therefore, in the in-situ solid-state battery preparation method of the present invention, when using an AC sine wave pulse waveform, if other pulse parameters remain unchanged, the current amplitude range can be the 0.5C-4C range corresponding to Examples 6-9, and more preferably the 1C-3C current amplitude range corresponding to Examples 7-8. Regarding this preferred 1C-3C range, when comparing other embodiments, a current amplitude of -2C to +2C is more preferably used.

[0093] Examples 10-13: Effects of different frequencies of pulse heating

[0094] Examples 10-13 aim to observe the effect of pulse current frequency on polymerization effect when an AC sine wave is applied for battery heating and curing. Examples 10-13 use the lithium battery shown in Table 1 and the first type of precursor shown in Table 2. In step (6), the most preferred total pulse current application time of 1800s determined in Examples 2-5 and the most preferred current amplitude of -2C to +2C determined in Examples 6-9 are used. Polymerization experiments are carried out according to the AC sine waves with different current frequencies applied according to Table 5, and the corresponding test results shown in Table 5 are obtained.

[0095] Table 5

[0096]

[0097] Based on the test results shown in Table 5, it is evident that Examples 10-13 all successfully completed the heating and curing of the lithium battery. However, Example 12 undoubtedly exhibits better polymerization uniformity, smaller areal density deviation, higher capacity retention after 200 cycles at 1C, and a smaller DCR increase. Therefore, in the in-situ solid-state battery preparation method of the present invention, when using an AC sine wave pulse waveform, if other pulse parameters remain unchanged, the current frequency range can be the 5-1000Hz range corresponding to Examples 10-13, and more preferably 20Hz corresponding to Example 12. Therefore, when making relevant comparisons of other embodiments, a current frequency range of 10-20Hz can be used, for example.

[0098] Based on embodiments 2 to 13 above, for AC sine waves, the most preferred set of pulse parameters was determined to be: the pulse parameters corresponding to embodiment 3, with a current amplitude of -2C to +2C, a current frequency of 20Hz, and a total application time of 1800s. Therefore, when comparing other embodiments, this optimal set of pulse parameters can be preferred.

[0099] Examples 14-16 illustrate the effects of pulse heating on different types of precursors.

[0100] Examples 14-16 aim to observe the effects of the in-situ solid-state battery preparation method of the present invention on different types of precursors. Examples 14-16 are relative to Examples 2-13 of the first type of precursor in Table 2 (taking Example 3 with the optimal pulse parameters as an example), the second type, third type, and fourth type of precursors. Step (6) involves applying an AC sine wave with the optimal pulse parameters as shown in Table 6 below for preparation and testing, and the corresponding test results are obtained.

[0101] Table 6

[0102]

[0103] Based on the test results shown in Table 6, it is easy to see that, under the same pulse parameters, when the preparation method of the in-situ solid-state battery of the present invention is applied to the first, second, third and fourth types of precursors shown in Table 2, in-situ solid-state batteries with good polymerization uniformity, small areal density deviation, high capacity retention and small DCR increase after 200 cycles at 1C can be prepared.

[0104] Examples 17-23: Effects of different pulse waveforms in pulse heating

[0105] Examples 17-23 aim to observe the effect of applying pulses of different waveforms to heat and cure the battery. Examples 17-23 are for the lithium battery shown in Table 1 and the first type of precursor shown in Table 2. In step (6), the optimal pulse parameters for AC sine waves determined in Examples 2-13 above are used (for comparison with Example 3 as an example). Different waveform pulses as shown in Table 7 are applied and the corresponding test results are obtained.

[0106] Examples 20-23 all target DC-AC sine waves, but based on the different heating methods and DC participation, they are divided into three types of simultaneous AC-DC heating methods, as shown in Table 8: Example 20, which uses alternating AC and DC heating, and Examples 21-23. The specific descriptions are as follows:

[0107] 1) Example 20, alternating AC and DC heating method: DC and AC alternate charging and heating, wherein the DC power is 1C; DC participates in one charging within 900s, and participates in a total of two charging within 1800s, each lasting 10s.

[0108] 2) Example 21, First type of AC and DC simultaneous heating method: DC power is 1C; DC participates in one charge within 900s, and participates in a total of two charges within 1800s, each lasting 10s.

[0109] 3) Example 22, Second type of AC and DC simultaneous heating method: DC power is 1C; DC participates in one charge within 900s, and participates in a total of two charges within 1800s, each lasting 15s.

[0110] 4) Example 23, the third type of AC and DC simultaneous heating method: DC power is 1C; DC participates in one charge within 900s, and participates in a total of two charges within 1800s, each lasting 20s.

[0111] Table 7

[0112]

[0113]

[0114] Table 8

[0115]

[0116] Based on the test results shown in Table 7, it is easy to see that various in-situ solid-state battery preparation methods of the present invention can be based on various pulse waveforms. Under the condition that the pulse parameters are basically the same, the AC square wave, AC sawtooth wave, AC triangular wave and DC-AC sine wave with alternating AC and DC heating used in Examples 17 to 20 can all achieve a polymerization effect close to that of the AC sine wave in Example 3. When using DC-AC sine wave with simultaneous AC and DC heating, as shown in Table 8, Examples 21 to 23 can also achieve a good polymerization effect by adjusting the time when DC participates in charging.

[0117] Examples 24-25: Effects of different types of batteries with pulse heating

[0118] Examples 24 and 25 aim to observe the effects of applying the in-situ solid-state battery preparation method of the present invention to different types of batteries. Example 24 corresponds to the aluminum-ion battery in Table 1, and Example 2 corresponds to the sodium-ion battery in Table 1, adapting to different battery types. Example 24 can use the fifth type of precursor in Table 1, while the sodium-ion battery in Example 25 can use the sixth type of precursor. Examples 24-25 all use the AC sine wave with the optimal pulse parameters corresponding to Example 3, and can be compared with Example 3. Based on this, the test results are shown in Table 9 below.

[0119] Table 9

[0120]

[0121] Based on the test results shown in Table 9, it is easy to see that, under the same pulse parameters, when the in-situ solid-state battery preparation method of the present invention is applied to the various types of batteries in Table 1, in-situ solid-state batteries with good polymerization uniformity, small areal density deviation, high capacity retention rate and small DCR increase after 200 cycles at 1C can be prepared.

[0122] Comparative Examples 2-3 did not employ the pulse heating method of this invention.

[0123] Comparative Examples 2 and 3 were designed to observe the effect of heating and curing batteries using conventional thermal polymerization methods. Comparative Example 2 used the first type of precursor shown in Table 2, and Comparative Example 3 used the second type of precursor shown in Table 2. The thermal polymerization temperature for Comparative Examples 2 and 3 was 60°C, and the duration was 24 hours. Based on this, the test results are shown in Table 10, and the test results for Comparative Examples 2 and 3 are compared with those for Examples 3 and 14, which used the same type of precursor.

[0124] Table 10

[0125]

[0126] Based on the test results shown in Table 10, it is easy to see that compared with Examples 3 and 14, Comparative Examples 2-3 have poorer polymerization effects, mainly manifested in larger areal density deviations and generally lower polymerization uniformity, resulting in a larger increase in DCR. Furthermore, the polymerization time of this thermal polymerization method is longer, up to 24 hours.

[0127] Comparative Examples 4 and 5 did not employ the pulse heating method of this invention.

[0128] Comparative Examples 4 and 5 were designed to observe the effect of heating and curing the battery using direct current. Comparative Example 4 used the first type of precursor shown in Table 2, and Comparative Example 5 used the second type of precursor shown in Table 2. The direct current used in Comparative Examples 4 and 5 had a current amplitude of 2C, a frequency of 10Hz, and an application time of 1800s. Based on this, the test results are shown in Table 11, and the test results of Comparative Examples 4 and 5 are compared with those of Examples 3 and 14, which used the same type of precursor and pulse parameters.

[0129] Table 11

[0130]

[0131] Based on the test results shown in Table 11, it is easy to see that the polymerization effect of Comparative Examples 4-5 is worse than that of Examples 3 and 14, mainly due to more severe aging, which is reflected in a larger increase in DCR.

[0132] In summary, the in-situ curing battery preparation method of the present invention applied in Examples 2-25 showed good polymerization effect of pulse-initiated precursor polymerization. Both the polymerization uniformity (reflected in the areal density deviation) and the degree of aging (reflected in the increase of DCR) were within acceptable range under the conditions of non-batch mass production of battery cells.

[0133] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing an in-situ solid-state battery, characterized in that, The preparation method includes: In-situ cured electrolyte precursor is injected into the cell to obtain the battery to be cured; and A pulsed current is applied to the electrodes of the battery to be cured to heat and cure the in-situ cured electrolyte precursor, thereby obtaining a solid-state battery. The electrodes are in an isothermal temperature field at any time during the heating process, and the waveform of the pulsed current is selected from either an AC sine wave or an alternating DC-AC sine wave.

2. The preparation method according to claim 1, characterized in that, The waveform of the pulse current is an alternating sine wave; The frequency of the pulse current is 0.1Hz-100kHz; The amplitude of the pulse current is 0.5C-5C; as well as The total application time of the pulse current is 5-60 minutes.

3. The preparation method according to claim 2, characterized in that, The frequency of the pulse current is 5Hz-1000Hz.

4. The preparation method according to claim 3, characterized in that, The frequency of the pulse current is 10Hz-20Hz.

5. The preparation method according to claim 2, characterized in that, The amplitude of the pulse current is 1C-3C.

6. The preparation method according to claim 2, characterized in that, The total application time of the pulse current is 20-30 minutes.

7. The preparation method according to claim 1, characterized in that, The waveform of the pulse current is a DC-AC sine wave; The frequency of the pulse current is 0.1Hz-100kHz; The amplitude of the AC current and the DC battery in the pulse current is 0.5C-5C; as well as The total application time of the pulsed current is 5-60 minutes, wherein the DC current and AC current in the DC-AC sine wave are applied alternately.

8. The preparation method according to claim 7, characterized in that, The frequency of the pulse current is 5Hz-1000Hz.

9. The preparation method according to claim 8, characterized in that, The frequency of the pulse current is 10Hz-20Hz.

10. The preparation method according to claim 7, characterized in that, The amplitude of the AC current and the DC battery in the pulse current is 1C-3C.

11. The preparation method according to claim 7, characterized in that, The total application time of the pulse current is 20-30 minutes.

12. The preparation method according to claim 7, characterized in that, The DC current is applied only once within a total application time of 900s, and each application lasts for 10s-20s.

13. The preparation method according to claim 1, characterized in that, Before injecting the in-situ solidified electrolyte precursor into the battery cell, the preparation method further includes: The polymer monomer, initiator, organic solvent, lithium salt and additives are mixed to obtain the in-situ cured electrolyte precursor.

14. The preparation method according to claim 13, characterized in that, The polymer monomer is selected from any one of the following: Monomers containing unsaturated carbon-carbon double bonds; Cyclic monomers that can undergo ring-opening polymerization; and Monomers containing polymerizable reactive functional groups.

15. The preparation method according to claim 13, characterized in that, The initiator is selected from any one of the following: azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl, diisopropylbenzene peroxide, dibenzoyl peroxide, and ammonium persulfate.

16. An in-situ solid-state battery, characterized in that, The in-situ solid-state battery is prepared by the preparation method according to any one of claims 1-15.

17. The in-situ solid-state battery according to claim 16, characterized in that, The in-situ solid-state battery is any one of lithium-ion batteries, magnesium-ion batteries, zinc-ion batteries, and aluminum-ion batteries.

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