Method for measuring safe use temperature of solid electrolyte

Abstract

The invention relates to a method for measuring the safe use temperature of a solid electrolyte and a method for controlling the safe operation of a battery. The puncture function of the dynamic mechanical analyzer is utilized to quantitatively simulate the temperature when the solid electrolyte is punctured in the lithium dendrite growth process, so that whether the electrolyte is applicable or not is judged according to the working temperature of the battery, the safety performance of the battery is pre-judged, and an indirect method is provided for judging the safety performance of the battery using the solid electrolyte.

Description

Technical Field

[0001] The present invention relates to the technical field related to lithium batteries, and in particular to a method for measuring the safe operating temperature of a solid electrolyte and a method for controlling the safe operation of a battery. Background Art

[0002] Dendrites are a general term for irregular lithium deposits. Dendrites grow from the surface of the negative electrode and can pierce the separator and contact the battery's positive electrode material, causing electrical contact between the positive and negative electrodes. This short circuit is often accompanied by thermal runaway, which can cause electrolyte fires and battery explosions, shortening the battery's cycle life and complicating its safe use. The safety concerns associated with the formation of branch-like lithium dendrites during the negative electrode deposition process have limited the practical application of lithium-ion batteries.

[0003] One approach to suppressing lithium dendrite growth is to develop solid-state electrolytes with high mechanical modulus. However, numerous studies have shown that due to inherent defects in solid-state electrolytes and poor interfacial behavior, dendrite growth remains a serious problem in actual solid-state metal lithium batteries. Furthermore, dendrite growth in solid-state electrolytes can penetrate the electrolyte more rapidly than in liquid batteries, leading to more severe safety issues. Due to the fundamentally different physical and chemical environments in solid and liquid electrolytes, the growth mechanism of lithium dendrites in solid-state batteries is even more complex.

[0004] When the temperature is below the glass transition temperature, the polymer used as a solid electrolyte is in a glassy state, in which molecular mobility is low and chain segments cannot move. When the temperature exceeds the glass transition temperature, the polymer changes from a glassy state to a highly elastic state, in which molecular mobility increases, macromolecular segments move, and large elastic deformation occurs when subjected to force. As the temperature gradually increases, the mechanical properties of the polymer decrease, and accordingly, its resistance to lithium dendrite penetration also decreases.

[0005] Puncture resistance refers to the mass of a needle-shaped object applied to a film sample to penetrate it. It indicates the tendency of the film to short-circuit during assembly. Because the electrolyte membrane is sandwiched between the uneven positive and negative electrodes, it must withstand significant pressure. To prevent short circuits, the electrolyte membrane must possess a certain level of puncture resistance.

[0006] Therefore, it is desirable to provide a method for determining the temperature at which the solid electrolyte is punctured by lithium dendrites, and then to predict the safety performance of the battery in advance based on the operating temperature of the battery. Summary of the Invention

[0007] Problems to be solved by the invention

[0008] To determine the temperature at which a solid electrolyte is punctured by lithium dendrites, a commonly known method utilizes a specific lithium-ion battery separator thermal penetration test device. This method can not only simulate the separator's thermal penetration capability at different temperatures, but also simulate and test the separator's puncture resistance under tension. However, this method controls the puncture needle to penetrate the separator at a constant temperature and determines the separator's thermal penetration performance by comparing its horizontal and vertical widths. This method can only simulate the separator's thermal penetration capability at different constant temperatures.

[0009] However, because the mechanical properties of solid electrolytes change with battery temperature, it is impossible to quantify the electrolyte's puncture rate at a certain temperature when its mechanical properties change. There is still a need to provide a method that can quantitatively simulate the puncture of solid electrolytes during lithium dendrite growth, determine the safe operating temperature of solid electrolytes, and then predict the puncture resistance of solid electrolyte membranes, thereby providing new ideas and methods for achieving safe and efficient solid-state batteries.

[0010] Therefore, the present invention is intended to provide a method for measuring the safe operating temperature of a solid electrolyte as an indirect method for judging the safety performance of a battery using the solid electrolyte, as well as a method for controlling the safe operation of the battery.

[0011] Solutions for solving problems

[0012] To address the aforementioned issues, the inventors conceived of using a dynamic mechanical analyzer to measure the critical temperature at which lithium dendrites penetrate a solid-state electrolyte membrane, hoping to conduct the test in a repeatable and simple manner. The inventors discovered that by quantitatively simulating the temperature at which a solid-state electrolyte resists lithium dendrite penetration during battery charge and discharge using a dynamic mechanical analyzer, they could determine the electrolyte's suitability based on the battery's operating temperature and thus predict the battery's safety performance.

[0013] To this end, the present invention provides a method for measuring the safe operating temperature of a solid-state electrolyte. By measuring the puncture temperature of the solid-state electrolyte using a dynamic mechanical analyzer, the safe operating temperature range of the solid-state electrolyte can be determined, thereby determining whether the electrolyte is suitable for use. Furthermore, the present invention provides a method for controlling the safe operation of a battery. By obtaining the safe operating temperature of the solid-state electrolyte, the safe operating temperature of the battery can be determined, and automatic battery protection measures can be implemented when the battery operating temperature exceeds the minimum safe operating temperature of the solid-state electrolyte.

[0014] Specifically, the present invention relates to the following contents.

[0015] In order to achieve the above invention purpose, the present invention adopts the following technical solutions:

[0016] [1] A method for measuring the safe operating temperature of solid electrolytes.

[0017] The method comprises the steps of (1) forming the solid electrolyte into a thin film, and (2) using a dynamic mechanical analyzer to measure the temperature of the solid electrolyte when it is punctured, thereby determining the safe operating temperature range of the solid electrolyte.

[0018] [2] The method according to [1], wherein the solid electrolyte is at least one selected from an organic polymer solid electrolyte or an organic-inorganic composite solid electrolyte.

[0019] [3] The method according to [2], wherein the organic polymer solid electrolyte comprises a polymer and a lithium salt.

[0020] [4] The method according to [2], wherein the organic-inorganic composite solid electrolyte comprises a polymer, a lithium salt, and ceramic particles, and the ceramic particles include at least one of an oxide, a nitride, a boride, and an inorganic ceramic solid electrolyte.

[0021] [5] The method according to [4], wherein the inorganic ceramic solid electrolyte comprises at least one of lithium lanthanum zirconium oxide, lithium lanthanum titanate oxide, tantalum-doped lithium lanthanum zirconium oxide, aluminum-doped lithium lanthanum zirconium oxide, lithium germanium phosphosulfide, lithium phosphosulfur chloride and lithium germanium aluminum phosphate.

[0022] [6] The method according to any one of [1] to [5], wherein the solid electrolyte is made into a thin film having a size of 10-70 mm in length × 10-70 mm in width × 0.005-2 mm in thickness.

[0023] [7] The method according to any one of [1] to [6], wherein measuring the temperature of the solid electrolyte when it is pierced using a dynamic mechanical analyzer comprises:

[0024] The solid electrolyte film is placed on the puncture fixture in the dynamic mechanical analyzer and the film is clamped. Pressure is applied to the film using a puncture needle. The temperature is increased and the relationship between the force value and the temperature is recorded. When the film is punctured, the force value changes significantly, thereby obtaining the temperature of the solid electrolyte when it is punctured.

[0025] [8] The method according to [7], wherein the pressure ranges from 0.01 to 9.8 N.

[0026] [9] The method according to [7] or [8], wherein the temperature is increased from room temperature at a rate of 0.01-20°C / min, preferably 0.1-10°C / min, more preferably 1-5°C / min.

[0027]

[10] The method according to any one of [7] to [9], wherein the diameter of the tip of the needle is 0.1-1 mm, and the angle of the tip of the needle relative to the surface of the film is in the range of 1-89°, preferably 30-89°, and more preferably 50-89°.

[0028]

[11] A method for controlling safe operation of a battery, the method comprising:

[0029] Step S1, using the method described in any one of [1]-

[10] to obtain the safe operating temperature T1 of the solid electrolyte,

[0030] Step S2, measuring the temperature T2 of the solid electrolyte during the assembly process,

[0031] Step S3, compare T1 and T2, and execute automatic protection measures when T2 ≥ T1-10°C.

[0032]

[12] The method according to

[11] , wherein in step S2, the temperature T2 is measured by a temperature sensor.

[0033]

[13] The method according to

[11] or

[12] , wherein in step S3, automatic protection measures are performed when T2 ≥ T1-5°C.

[0034]

[14] Use of a dynamic mechanical analyzer in measuring the puncture temperature of a solid electrolyte.

[0035] Effects of the Invention

[0036] The above technical solution of the present invention has the following beneficial effects:

[0037] (1) The present invention can not only more accurately simulate the puncture resistance of the solid electrolyte membrane when it is pierced by lithium dendrites during a sudden temperature change or as the temperature slowly increases, but also is simple and safe to operate, does not require the use of special instruments, and can more easily obtain the puncture resistance performance results of the solid electrolyte membrane.

[0038] (2) The present invention can circumvent the limitations of battery type, external ambient temperature and other conditions, and has great universality.

[0039] (3) The present invention utilizes the puncture function of a dynamic mechanical analyzer to quantitatively simulate the temperature when lithium dendrites pierce the solid electrolyte during growth, providing an indirect method for determining the safety performance of batteries using the solid electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the puncture test of the dynamic mechanical analyzer.

[0041] Figure 2 Schematic diagram of the needle, wherein (a) is a morphological photograph of the needle, and (b) is a schematic diagram of the state of the needle when in contact with the film surface. DETAILED DESCRIPTION

[0042] The following describes embodiments of the present invention, but the present invention is not limited thereto. The present invention is not limited to the various configurations described below; various modifications may be made within the scope of the invention claims, and embodiments obtained by appropriately combining different embodiments and appropriately combining the technical means disclosed in the examples are also included in the technical scope of the present invention. In addition, all documents listed in this specification are cited as references in this specification.

[0043] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0044] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints A and B.

[0045] In this specification, unless otherwise specified, "multiple" in "multiple", "multiple", "many" and the like means a numerical value of 2 or more.

[0046] In this specification, the term “substantially”, “generally” or “essentially” means that the error is less than 5%, or less than 3%, or less than 1% compared with the relevant perfect standard or theoretical standard.

[0047] In this specification, unless otherwise specified, "%" means percentage by mass.

[0048] In this specification, when "room temperature" or "normal temperature" appears, the temperature may generally be 10-37°C, or 15-35°C.

[0049] In this specification, the meanings of “may” or “can” include both existence and non-existence, and both performing a certain process and not performing a certain process.

[0050] Throughout this specification, “optional” and “optionally” mean that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

[0051] The term "comprises" and any variations thereof in the specification and claims of the present invention and the accompanying drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0052] In this specification, references to "some / certain / preferred embodiments," "embodiments," etc., mean that the specific elements (e.g., features, structures, properties, and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it should be understood that the elements may be combined in any suitable manner in various embodiments.

[0053] <First Aspect>

[0054] A first aspect of the present invention relates to a method for measuring the safe operating temperature of a solid electrolyte, which comprises the steps of (1) forming the solid electrolyte into a thin film, and (2) using a dynamic mechanical analyzer to measure the temperature of the solid electrolyte when it is punctured, thereby determining the safe operating temperature range of the solid electrolyte.

[0055] Solid-state electrolytes offer advantages such as flame retardancy, corrosion resistance, non-volatility, and leak resistance, overcoming the processing, safety, and service life challenges of liquid electrolytes. They act as ionic conductors, enabling lithium ion transfer between the positive and negative active materials. They also function as separators to separate the positive and negative electrodes, preventing internal short circuits. The solid-state electrolyte is selected from at least one of an organic polymer solid electrolyte and an organic-inorganic composite solid electrolyte.

[0056] Organic polymer solid electrolytes have the advantages of low reactivity with electrode materials and good flexibility. Organic polymer solid electrolytes contain polymers and lithium salts and can be considered as solid solution systems formed by directly dissolving lithium salts in a polymer matrix. In the polymer matrix, there are two parts: the crystalline region and the amorphous region of the polymer. The functional groups in the polymer dissolve ions through coordination. The dissolved ions are mainly present in the amorphous region, and ion conduction is mainly achieved through the movement of chain segments in the amorphous region. For example, polymer solid electrolytes mainly include: polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), etc.

[0057] Organic-inorganic composite solid electrolytes, created by combining polymers with inorganic materials, combine the properties of both organic and inorganic solid electrolytes, offering excellent overall performance and effectively improving battery life and safety. Organic-inorganic composite solid electrolytes can be broadly categorized into layered polymer-inorganic ceramic composite solid electrolytes, hybrid polymer-inorganic composite solid electrolytes, and hybrid polymer-inorganic composite solid electrolytes with specific structures.

[0058] Specifically, the organic-inorganic composite solid electrolyte comprises a polymer, a lithium salt, and inorganic particles, with the highly ionic conductive inorganic particles dispersed within the polymer. This organic-inorganic composite solid electrolyte can both reduce the degree of polymer crystallinity and enable the migration and conduction of lithium ions in the inorganic electrolyte, thereby significantly improving the ionic conductivity of the composite solid electrolyte.

[0059] The inorganic particles can be provided in the form of nanoparticles, nanowires / rods, or two-dimensional sheet materials. The inorganic particles are further preferably ceramic particles, such as titanium dioxide (TiO2), aluminum oxide (Al2O3), zirconium oxide (ZrO2), and silicon dioxide (SiO2). Ceramic particles can enhance the mechanical properties and heat resistance of the composite solid electrolyte and reduce the crystallinity of the polymer matrix.

[0060] In step (1), the solid electrolyte is made into a sheet-like film with a size of 10-70 mm×10-70 mm in width×0.005-2 mm in thickness.

[0061] If the solid electrolyte membrane is too thick, it will be detrimental to battery miniaturization. In solid-state batteries, lithium ions form branch-like lithium dendrites during the deposition process at the negative electrode. The sharp structure of the lithium dendrites can pierce the electrolyte membrane, causing an internal short circuit in the battery, resulting in thermal runaway and causing combustion or explosion. If the solid electrolyte membrane is too thin, the lithium dendrites will quickly pierce the membrane, causing electrical contact between the positive and negative electrodes, which is detrimental to battery safety.

[0062] In step (2), in a dynamic mechanical analyzer, a needle is used to apply pressure to the film, the temperature is increased, and the relationship between the position of the needle and the temperature is recorded, thereby obtaining the temperature T1 when the solid electrolyte is pierced.

[0063] First, the film is placed in the puncture fixture of the dynamic mechanical analyzer and clamped. The electrolyte membrane is sandwiched between the positive and negative electrodes and needs to remain flat. By clamping the film, the solid electrolyte membrane remains flat, closely simulating the changes in behavior of the solid electrolyte membrane due to temperature changes within the battery.

[0064] Then, a certain pressure is applied to the film using a needle, the tip diameter of the needle is 0.1-1 mm, and the angle of the tip of the needle relative to the film surface is in the range of 1-89°, preferably 30-89°, more preferably 50-89°. More specifically, as Figure 2 As shown, Figure 2 a is a photo of the morphology of the needle, Figure 2 b is a schematic diagram of the state of the needle when it contacts the film surface. As lithium dendrites are unevenly deposited on the negative electrode surface, irregular protrusions are formed, which generally present an angle in the range of θ = 1-89° relative to the solid electrolyte membrane.

[0065] The range of applied pressure is 0.01-9.8N, and the battery is usually tested for charge and discharge under high temperature conditions and normal temperature conditions. By testing a known solid electrolyte membrane and measuring its pressure at a known puncture temperature and when punctured at room temperature, the puncture pressure range when the charge and discharge test is carried out under high temperature conditions and normal temperature conditions is shown. By setting the applied constant pressure within the above range, the effect of temperature on the solid electrolyte under the growth conditions of lithium dendrites can be reflected. If the applied pressure is too large, the solid electrolyte will be punctured quickly, and reasonable test results cannot be obtained. If the applied pressure is too small, it is impossible to simulate the mechanical stress exerted by the tip of the lithium dendrite on the solid electrolyte membrane as the lithium dendrite grows.

[0066] Next, the temperature is raised according to the program, and the relationship between the force and temperature is recorded. When the film is pierced, the force changes significantly, such as a sudden drop in force, thereby obtaining the temperature T1 when the solid electrolyte is pierced by the lithium dendrite.

[0067] Start heating from room temperature at a rate of 0.01-20°C / min, preferably 0.1-10°C / min, and more preferably 1-5°C / min. Polymer solid electrolytes undergo viscoelastic changes with battery temperature. A rapid temperature increase can indicate problems with the electrolyte membrane in a short period of time due to a sudden temperature change, while a slow temperature increase can indicate problems with the electrolyte membrane after a long period of time to fully deform with increasing temperature.

[0068] As a specific embodiment, a dynamic mechanical analyzer is used, and the film is placed on the puncture fixture of the analyzer to clamp the film. A certain pressure is applied to the film using a needle, and the temperature is increased according to a program. As the temperature rises and time increases, the sample deforms, and the relationship between the force and temperature is recorded. When the film is punctured, a significant change in the force is observed, thereby determining the temperature at which the solid electrolyte is pierced by the lithium dendrite, and further determining the safe operating temperature range of the solid electrolyte.

[0069] Therefore, the present invention also relates to the use of a dynamic mechanical analyzer to measure the penetration temperature of solid electrolytes. The inventors unexpectedly discovered that using a dynamic mechanical analyzer to measure the temperature of a solid electrolyte when it is penetrated by lithium dendrites is simple, convenient, pollution-free, and non-toxic to the human body. Furthermore, programmable temperature control offers higher precision than oil bath heating and a wider test temperature range.

[0070] <Second Aspect>

[0071] The second aspect of the present invention relates to a method for controlling the safe operation of a battery, which includes step S1, using the above method to obtain the safe operating temperature T1 of the solid electrolyte; step S2, measuring the temperature T2 of the solid electrolyte membrane during the assembly process; step S3, comparing T1 with T2, and executing automatic protection measures when T2 ≥ T1-10°C.

[0072] In step S1, the solid electrolyte material of this aspect is the same as that in the above <first aspect>, and will not be described again here.

[0073] The puncture function of a dynamic mechanical analyzer quantitatively simulates the temperature at which lithium dendrites pierce solid electrolytes during growth. This simple, convenient, pollution-free, and non-toxic method is also non-toxic to humans. Furthermore, programmable temperature control offers greater precision than oil bath heating and a wider test temperature range. Therefore, it is more convenient to determine suitable solid electrolyte membranes for lithium-ion batteries.

[0074] In step S2, the temperature T2 of the solid electrolyte membrane during the assembly process is measured by a battery temperature monitoring system.

[0075] To reduce the tendency of the membrane to short-circuit during assembly, it is necessary to monitor the temperature experienced by the solid electrolyte membrane during assembly. Multi-point temperature measurements can be performed to assess the temperature fluctuations and distribution across the membrane.

[0076] Temperature sensors can be categorized by their measurement method into contact and non-contact types. Non-contact temperature sensors, such as radiation thermometers, are suitable for more convenient temperature monitoring of the solid electrolyte membrane during assembly. Contact temperature sensors, such as resistance thermometers, thermistors, and thermocouples, are suitable for more accurate temperature monitoring of the solid electrolyte membrane during assembly.

[0077] In step S3, automatic protection measures are executed when T2 ≥ T1 - 10°C.

[0078] Through the battery temperature monitoring system, inputting the alarm threshold of T2 ≥ T1-10°C activates the alarm program. Automatic protection measures are implemented once T2 ≥ T1-10°C is detected. The monitoring system includes temperature monitoring nodes and a main control unit. Temperature monitoring nodes can be distributed across the solid electrolyte membrane, collecting temperature information from each area and communicating with the outside world through the main control unit. This allows for timely detection of abnormal conditions based on the alarm program.

[0079] Example

[0080] The present invention will be described in detail below by way of examples. The examples of the examples are intended to explain the present invention and are not to be construed as limiting the present invention. Where specific techniques or conditions are not specified in the examples, the methods were performed according to the techniques or conditions described in the literature in the art or according to the product specifications. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be obtained commercially.

[0081] Example 1

[0082] like Figure 1 As shown, a 40mm×40mm×0.03mm thin film sample of an organic polymer solid electrolyte was placed in the puncture fixture of a dynamic mechanical analyzer and clamped, with a 0.5mm diameter needle approaching the sample. Heating was initially performed at a 3°C / min heating rate while simultaneously applying a force of 0.05N to the needle. The relationship between force and temperature was recorded. As the temperature increased and time increased, the force value significantly changed when the sample was punctured, indirectly providing the temperature at which the solid electrolyte was punctured by the lithium dendrite.

[0083] Example 2

[0084] A 40mm x 40mm x 0.13mm thin film sample of the organic-inorganic composite solid electrolyte was placed in the puncture fixture of a dynamic mechanical analyzer and clamped, with a 0.5mm diameter needle brought close to the sample. Heating was initiated at a 3°C / min heating rate while simultaneously applying a 0.1N force to the needle. The relationship between force and temperature was recorded. As the temperature increased and time increased, the force value significantly changed when the sample was punctured, indirectly providing an estimate of the temperature at which the solid electrolyte was pierced by the lithium dendrite.

[0085] It can be seen from the above-mentioned Examples 1 and 2 that not only can the puncture resistance of the solid electrolyte membrane when it is pierced by lithium dendrites during a sudden temperature change or as the temperature slowly rises be simulated more accurately, but the operation is simple and safe, and no special instruments are required, making it easier to obtain the puncture resistance performance results of the solid electrolyte membrane.

[0086] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

[0087] Industrial applicability

[0088] The present invention utilizes the puncture function of a dynamic mechanical analyzer to quantitatively simulate the temperature when lithium dendrites pierce a solid electrolyte during growth, and can indirectly judge the safety performance of a battery using the solid electrolyte.

Claims

1. A method for measuring the safe operating temperature of a solid electrolyte, characterized in that: The method comprises the steps of (1) forming the solid electrolyte into a thin film, and (2) using a dynamic mechanical analyzer to measure the temperature of the solid electrolyte when it is punctured, thereby determining the safe operating temperature range of the solid electrolyte. 2 . The method according to claim 1 , wherein the solid electrolyte is at least one selected from an organic polymer solid electrolyte or an organic-inorganic composite solid electrolyte. 3 . The method according to claim 2 , wherein the organic polymer solid electrolyte comprises a polymer and a lithium salt.

4. The method according to claim 2, wherein the organic-inorganic composite solid electrolyte comprises a polymer, a lithium salt, and ceramic particles, and the ceramic particles include at least one of an oxide, a nitride, a boride, and an inorganic ceramic solid electrolyte.

5. The method according to claim 4, wherein the inorganic ceramic solid electrolyte comprises at least one of lithium lanthanum zirconium oxide, lithium lanthanum titanate oxide, tantalum-doped lithium lanthanum zirconium oxide, aluminum-doped lithium lanthanum zirconium oxide, lithium germanium phosphosulfide, lithium phosphosulfur chloride, and lithium germanium aluminum phosphate.

6. The method according to any one of claims 1 to 5, wherein the solid electrolyte is made into a thin film having a size of 10-70 mm in length x 10-70 mm in width x 0.005-2 mm in thickness.

7. The method according to any one of claims 1 to 6, wherein measuring the temperature of the solid electrolyte when it is punctured using a dynamic mechanical analyzer comprises: The solid electrolyte film is placed on the puncture fixture in the dynamic mechanical analyzer and the film is clamped. Pressure is applied to the film using a puncture needle. The temperature is increased and the relationship between the force value and the temperature is recorded. When the film is punctured, the force value changes significantly, thereby obtaining the temperature of the solid electrolyte when it is punctured.

8. The method according to claim 7, wherein the pressure ranges from 0.01 to 9.8 N; Preferably, the temperature is increased from room temperature at a rate of 0.01-20°C / min, preferably 0.1-10°C / min, more preferably 1-5°C / min; Preferably, the diameter of the tip of the needle is 0.1-1 mm, and the angle of the tip of the needle relative to the film surface is in the range of 1-89°, preferably 30-89°, more preferably 50-89°.

9. A method for controlling safe operation of a battery, characterized in that: The method comprises the following: Step S1, obtaining a safe operating temperature T1 of the solid electrolyte using the method according to any one of claims 1 to 8, Step S2, measuring the temperature T2 of the solid electrolyte during the assembly process, Step S3, compare T1 and T2, and execute automatic protection measures when T2 ≥ T1-10°C; Preferably, in step S2, the temperature T2 is measured by a temperature sensor; Preferably, in step S3, automatic protection measures are performed when T2 ≥ T1-5°C.

10. Use of a dynamic mechanical analyzer in measuring the penetration temperature of a solid electrolyte.

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