Lithium ion battery, manufacturing method and internal measurement method

Abstract

The invention relates to the technical field of new energy industry, and discloses a lithium ion battery which comprises a battery cell, a measuring assembly and a shell, the measuring assembly comprises a first measuring optical fiber and a second measuring optical fiber, and the first measuring optical fiber can respond to temperature and modulate an optical signal; the second measuring optical fiber can respond to temperature and strain and modulate optical signals, the measuring assembly adopts a fiber bragg grating (FBG) to measure the interior of the lithium ion battery, double optical fibers are adopted to eliminate cross interference of the temperature and strain signals, and the accuracy and reliability of measurement of the internal state of the battery are improved. Meanwhile, according to the lithium ion battery, the measuring assembly is implanted into the battery cell in a lossless mode, sealing packaging is achieved through the shell, and the structural stability and the performance of the battery are guaranteed. The invention also provides a manufacturing method of the lithium ion battery and an internal measurement method of the lithium ion battery, which can also achieve the above beneficial effects.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy industry, and in particular to a lithium ion battery, a manufacturing method and an internal measurement method. BACKGROUND

[0002] With the continuous development of clean energy technology, high-performance rechargeable secondary batteries have been widely used in energy storage systems, electric vehicles, portable electronic devices and other fields. Among them, lithium ion batteries have become the mainstream battery technology due to their high energy density, excellent coulomb efficiency and long cycle life. However, the existing battery management system has shortcomings in real-time monitoring and accurate control, which brings new challenges to battery safety and performance optimization.

[0003] In the field of internal parameter monitoring of batteries, the existing technology often uses a single optical fiber sensor to measure the internal temperature or strain of the battery. However, the temperature and strain signals are coupled, which greatly reduces the accuracy and reliability of the measurement results. Moreover, the arrangement of the optical fiber sensor in the battery, the integration process with the battery cell, and the potential impact on the integrity of the battery package are all issues that need to be further studied and solved.

[0004] In addition, the existing internal measurement method of the battery is mostly implanted directly. This method will cause local deformation of the battery, which seriously affects the stability and reliability of the battery. In the context of the increasing demand for battery performance in the new energy industry, there is an urgent need for a new internal measurement structure that can ensure the performance of the battery without affecting the performance of the battery, and achieve accurate decoupling monitoring of temperature and strain signals, while having good long-term stability to meet the needs of complex application scenarios and promote the development of battery technology to a higher level. SUMMARY

[0005] The purpose of the present application is to provide a lithium ion battery, a manufacturing method and an internal measurement method to solve the problems of the related art and improve the accuracy and reliability of the internal measurement results of the lithium ion battery while ensuring the stability of the battery structure and the performance of the battery.

[0006] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0007] The present application provides a lithium ion battery, comprising:

[0008] a battery cell, the battery cell comprising a measurement substrate, the measurement substrate comprising a substrate body and a pole piece arranged on one side of the substrate body, the substrate body being connected to one side of the current collector of the pole piece;

[0009] A measuring assembly, comprising a first measuring fiber and a second measuring fiber, the first measuring fiber being connected with the measuring substrate, the first measuring fiber being capable of responding to a temperature signal; the second measuring fiber being connected with a side of the current collector of the pole piece close to the first measuring fiber, the second measuring fiber being capable of responding to a temperature and strain signal, the second measuring fiber being arranged in parallel with the first measuring fiber;

[0010] An outer shell, the outer shell wrapping the electric core, the first measuring fiber and the second measuring fiber being capable of being led out from the outer shell.

[0011] Preferably, the substrate body has a groove capable of accommodating the first measuring fiber and the second measuring fiber, the groove being a U-shaped groove with an opening facing the direction of the second measuring fiber.

[0012] Preferably, the first measuring fiber is externally sleeved with a protective sleeve, the protective sleeve being adhesively connected with the substrate body, and the second measuring fiber is adhesively connected with the side of the current collector of the pole piece.

[0013] Preferably, the substrate body is made of polylactic acid, high-temperature-resistant resin or ceramic material.

[0014] Preferably, the first measuring fiber and the second measuring fiber are both capable of being connected with an external fiber wavelength demodulator;

[0015] The fiber wavelength demodulator is also capable of being connected with an electronic recording device.

[0016] The application provides a manufacturing method of the lithium ion battery.

[0017] Step one, fixing the first measuring fiber on the substrate body as a temperature measuring fiber, and fixing the second measuring fiber on the side of the current collector of the pole piece close to the first measuring fiber, the second measuring fiber serving as a composite fiber, and the side of the current collector of the pole piece being connected with the substrate body.

[0018] Step two, encapsulating the electric core by the outer shell, and leading the first measuring fiber and the second measuring fiber out from the outer shell.

[0019] The application also provides an internal measuring method of the lithium ion battery, the first measuring fiber being used to respond to a temperature signal inside the lithium ion battery, the second measuring fiber being used to respond to a temperature and strain signal inside the lithium ion battery, and the wavelength changes of the first measuring fiber and the second measuring fiber being collected to realize decoupling of the temperature and strain signals inside the lithium ion battery.

[0020] Preferably, the differential algorithm is used to process the reflected wavelength drift data of the first measurement optical fiber and the second measurement optical fiber to realize decoupling of the temperature and strain signals inside the lithium ion battery.

[0021] Preferably, the differential algorithm formula is as follows:

[0022]

[0023] Δε k =(Δλ ε,T -Δλ T ) / S ε

[0024] Wherein, T is the temperature of the lithium ion battery, T0 is the initial temperature of the lithium ion battery, λ T is the wavelength of the first measurement optical fiber, is the initial wavelength of the first measurement optical fiber; Δε k is the strain of the lithium ion battery, Δλ ε,T is the wavelength change of the second measurement optical fiber, Δλ T is the wavelength change of the first measurement optical fiber; S T is the temperature sensitivity coefficient, S ε is the strain sensitivity coefficient, S T and S ε are obtained through laboratory calibration.

[0025] The present application has the following technical effects relative to the related art: the lithium ion battery of the present application comprises a cell, a measurement assembly and a shell, wherein the cell comprises a measurement substrate, the measurement substrate comprises a substrate body and a pole plate arranged on one side of the substrate body, and the substrate body is connected to the current collector side of the pole plate; the measurement assembly comprises a first measurement optical fiber and a second measurement optical fiber, the first measurement optical fiber is connected to the measurement substrate and can respond to a temperature signal; the second measurement optical fiber is connected to the current collector side of the pole plate close to the first measurement optical fiber and can respond to a temperature and strain signal, and the second measurement optical fiber is arranged in parallel with the first measurement optical fiber; the shell wraps the cell, and the first measurement optical fiber and the second measurement optical fiber can be led out from the shell.

[0026] The lithium-ion battery of the present invention has an internal measurement assembly, which includes a first measurement optical fiber and a second measurement optical fiber. The first measurement optical fiber can respond to temperature and modulate an optical signal, while the second measurement optical fiber can respond to temperature and strain and modulate an optical signal. The measurement assembly uses a fiber Bragg grating (FBG) to measure the interior of the lithium-ion battery. The dual optical fibers eliminate cross-interference between temperature and strain signals, improving the accuracy and reliability of the battery's internal state measurement. Furthermore, the lithium-ion battery of the present invention non-destructively embeds the measurement assembly within the battery cell and uses a sealed outer casing to ensure the battery's structural stability and performance.

[0027] The present invention also provides a method for manufacturing the above-mentioned lithium-ion battery and a method for measuring the internal state of the above-mentioned lithium-ion battery. Naturally, the method for manufacturing the lithium-ion battery and the method for measuring the internal state of the lithium-ion battery of the present invention can also achieve the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 A schematic structural diagram of a lithium-ion battery disclosed in an embodiment of the present invention;

[0030] Figure 2 This is a schematic structural diagram of a lithium-ion battery measurement substrate disclosed in an embodiment of the present invention;

[0031] Figure 3 This is a schematic structural diagram of a battery cell obtained by assembling a measurement substrate of a lithium-ion battery disclosed in an embodiment of the present invention in a stacked structure;

[0032] Figure 4 A schematic diagram of a lithium-ion battery measurement component disclosed in an embodiment of the present invention monitoring wavelength changes caused by temperature and strain during the cycling of the lithium-ion battery;

[0033] Figure 5 A schematic diagram of internal temperature changes of a lithium-ion battery disclosed in an embodiment of the present invention;

[0034] Figure 6 Schematic diagram of internal strain changes of a lithium-ion battery disclosed in an embodiment of the present invention.

[0035] In the figure: 1. measurement substrate; 2. measurement assembly; 3. substrate body; 4. pole piece; 5. first measurement optical fiber; 6. second measurement optical fiber; 7. groove. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0037] The present application aims to provide a lithium ion battery, a manufacturing method and an internal measurement method to solve the problems in the related art, improve the accuracy and reliability of internal measurement results of the lithium ion battery, and ensure the stability of the battery structure and the performance of the battery.

[0038] To make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0039] Embodiment one

[0040] The present embodiment provides a lithium ion battery, please refer to Figures 1-6 , comprising a cell, a measurement assembly 2 and a shell, wherein the cell comprises a measurement substrate 1, the measurement substrate 1 comprises a substrate body 3 and a pole piece 4 arranged on one side of the substrate body 3, and the substrate body 3 is connected to the current collector side of the pole piece 4; the measurement assembly 2 comprises a first measurement optical fiber 5 and a second measurement optical fiber 6, the first measurement optical fiber 5 is connected to the measurement substrate 1, and the first measurement optical fiber 5 can respond to a temperature signal; the second measurement optical fiber 6 is connected to the current collector side of the pole piece 4 close to the first measurement optical fiber 5, and the second measurement optical fiber 6 can respond to a temperature and strain signal, and the second measurement optical fiber 6 is arranged in parallel with the first measurement optical fiber 5; the shell wraps the cell, and the first measurement optical fiber 5 and the second measurement optical fiber 6 can be led out from the shell.

[0041] The lithium ion battery of the present application sets a measurement assembly 2 in the battery, the measurement assembly 2 comprises a first measurement optical fiber 5 and a second measurement optical fiber 6, the first measurement optical fiber 5 can respond to temperature and modulate light signals, and the second measurement optical fiber 6 can respond to temperature and strain and modulate light signals, the measurement assembly 2 uses a Bragg fiber grating (FBG) to measure the internal state of the lithium ion battery, the present application uses double optical fibers to eliminate the cross interference of temperature and strain signals, and improves the accuracy and reliability of the internal state measurement of the battery. At the same time, the lithium ion battery of the present application implants the measurement assembly 2 into the cell without damage, and realizes sealing and packaging by using the shell, thereby ensuring the stability of the battery structure and the performance of the battery.

[0042] It should be explained here that the pole piece 4 in the battery cell includes at least one positive pole piece 4 and at least one negative pole piece 4 to form positive and negative poles, and also includes a diaphragm between the positive and negative poles. The lithium ion battery also includes an electrolyte encapsulated in the shell to ensure that the lithium ion battery can smoothly charge and discharge. The positive pole, the negative pole, the diaphragm, and the electrolyte are all known to those skilled in the art, and will not be described here. It should also be explained that when the pole piece 4 in the battery cell is multiple, the second measuring optical fiber 6 is located on the side of the current collector of one of the pole pieces 4 close to the base body 3. At the same time, the base body 3 of the present application is made of a material that takes into account the electrolyte, so as to avoid the reaction between the base body 3 and the electrolyte affecting the normal operation of the lithium ion battery.

[0043] Specifically, the base body 3 has a groove 7 capable of accommodating the first measuring optical fiber 5 and the second measuring optical fiber 6. The groove 7 is a U-shaped groove with an opening facing the direction of the second measuring optical fiber 6. The present application provides the groove 7 on the base body 3 so that the first measuring optical fiber 5 and the second measuring optical fiber 6 are both located in the groove 7. The base body 3 is used to integrate the measuring assembly 2 and the battery cell to be sealed in the shell, realizing a zero-interference integrated mode of the measuring assembly 2 and the battery reaction components, which is suitable for laminated battery cells or wound battery cells without the need for additional modification of production equipment. In this specific embodiment, the diameters of the first measuring optical fiber 5 and the second measuring optical fiber 6 are both 80 μm, the thickness of the base body 3 is preferably 1.1 mm, and the depth of the groove 7 is greater than 80 μm, so as to ensure that the groove 7 can accommodate the first measuring optical fiber 5 and the second measuring optical fiber 6, and avoid the damage to the internal structure of the battery caused by the influence of the measuring assembly 2 on the reaction components of the battery cell.

[0044] In other specific embodiments that can be achieved by the present application, a protective sleeve can be provided outside the first measuring optical fiber 5. After the protective sleeve is provided, the first measuring optical fiber 5 is fixed in the groove 7. The protective sleeve provided outside the first measuring optical fiber 5 can effectively avoid mechanical damage to the first measuring optical fiber 5 and the second measuring optical fiber 6, ensure the working reliability of the measuring assembly 2, and also play a role in preventing interference.

[0045] In the present application, the first measuring optical fiber 5 is connected to the base body 3 after being provided with a protective sleeve, and the second measuring optical fiber 6 is connected to the side of the current collector of the pole piece 4. In practical applications, a high-chemical-resistance adhesive (such as high-chemical-resistance epoxy resin) can be used to fix the first measuring optical fiber 5 and the protective sleeve in the groove 7, and the second measuring optical fiber 6 can be adhered to the side of the current collector of the pole piece 4 by using the adhesive.

[0046] In the specific embodiment, the base body 3 is made of polylactic acid (PLA), high-temperature-resistant resin, or ceramic material. The base body 3 made of polylactic acid is environmentally friendly and flexible, which is conducive to improving the applicability of the battery. The base body 3 made of high-temperature-resistant resin has elastic material that can absorb the volume expansion stress of the battery during charging and discharging, thereby avoiding deformation and short circuit of the pole piece 4 and further improving the structural stability of the battery. The base plate body made of ceramic material has stable structure. In actual application, the base body 3 can also be made of other materials to meet different working conditions.

[0047] In the specific embodiment, the base body 3 has a rectangular sheet structure, and the base body 3 has a geometric symmetry structure with the center line of the length direction of the groove 7 as the symmetry axis. The geometric symmetry structure of the base body 3 and the selection of high-strength and corrosion-resistant materials ensure the stable response of the first measurement optical fiber 5 and the second measurement optical fiber 6 in long-term circulation, thereby significantly improving the accuracy and reliability of the internal state detection of the battery.

[0048] In actual application, the first measurement optical fiber 5 and the second measurement optical fiber 6 can be connected to an external optical fiber wavelength demodulator to measure the change of the wavelength (or frequency) of the transmitted optical signal in the first measurement optical fiber 5 and the second measurement optical fiber 6, and obtain the information of the external physical quantity (such as temperature and strain) by analyzing the wavelength offset.

[0049] In order to facilitate recording, the optical fiber wavelength demodulator can also be connected to an electronic recording device. The first measurement optical fiber 5 and the second measurement optical fiber 6 can be connected to the external optical fiber wavelength demodulator by a connecting line, and the optical fiber wavelength demodulator can be connected to the electronic recording device by a connecting line to construct a measurement system.

[0050] Embodiment two

[0051] The embodiment provides a manufacturing method of the lithium ion battery of embodiment one, including the following steps:

[0052] Step one, fix the first measurement optical fiber 5 on the base body 3 as a temperature measurement optical fiber, and fix the second measurement optical fiber 6 on the current collector side of the pole piece 4 close to the first measurement optical fiber 5, the second measurement optical fiber 6 as a composite optical fiber, and the current collector side of the pole piece 4 is connected with the base body 3;

[0053] Step two, package the battery cell by the shell, and lead out the first measurement optical fiber 5 and the second measurement optical fiber 6 from the shell.

[0054] The manufacturing method of the lithium ion battery of the application implants the first measurement optical fiber 5 and the second measurement optical fiber 6 into the groove 7 of the base body 3 without damage and integrates and seals with the current collector side of the pole piece 4, realizes the integration mode of zero interference between the measurement assembly 2 and the battery cell structure, and can be applied to the existing technology of the laminated or wound battery cell production line.

[0055] Example Three

[0056] The embodiment provides a manufacturing method of the lithium ion battery of example one, and comprises the following steps:

[0057] S1, a bare optical fiber is fixed on the current collector side of the single-sided coating pole piece 4 as a second measurement optical fiber 6, called a composite optical fiber, another optical fiber is arranged in the groove 7 of the base body 3 after being inserted into the protective sleeve as a first measurement optical fiber 5, called a temperature measurement optical fiber, the current collector side of the two single-sided coating pole pieces 4 is coated with an adhesive, and the base body 3 with the groove 7 and the first measurement optical fiber 5 is pasted and cured to form a measurement base 1 with double optical fibers arranged in parallel;

[0058] S2, the measurement base 1 is placed into the battery as a positive electrode or a negative electrode according to the coating property, and is closely arranged in the form of a stack or a winding together with a diaphragm, and the assembly of the battery with optical fibers is completed;

[0059] S3, the positive and negative pole tabs are respectively welded to the positive and negative electrodes of the battery, and are loaded into the shell together with the built-in measurement assembly 2; for square shell or soft package batteries, a hole is punched at the shell or top cover and the optical fiber outlet is epoxy sealed; for aluminum plastic film soft package, the optical fiber is simultaneously heat sealed when the edge is sealed;

[0060] S4, the matched electrolyte is injected under negative pressure and the packaging is completed, and after formation and sorting treatment, the lithium ion battery with high stability and built-in double FBG optical fiber measurement function is obtained.

[0061] Example Four

[0062] The embodiment provides a manufacturing method of the lithium ion battery of example one, and comprises the following steps:

[0063] The base body 3 is selected from a polylactic acid (PLA) film with a size of 58 mm in length, 45 mm in width and 1.1 mm in thickness.

[0064] A groove 7 with a width of 1 mm and a depth of 0.9 mm is etched on the PLA film by using a laser micro-processing device, so as to arrange two FBG optical fibers with a diameter of 80 μm.

[0065] The PLA film with the groove is placed on a vacuum platform, the first measurement optical fiber 5 with the protective sleeve is placed in the groove 7 by coating a trace amount of epoxy adhesive along the inside of the groove 7, and the first measurement optical fiber 5 with the protective sleeve is tightly attached to the groove bottom by light pressing with a flexible scraper; at the same time, the second measurement optical fiber 6 is directly attached to the current collector side of the single-sided coating pole piece 4 through the adhesive.

[0066] The coated substrate body 3, the measurement assembly 2 and the pole piece 4 are all placed in an 80°C oven for curing for 30 minutes and left to stand for 24 hours.

[0067] After thorough curing, a layer of epoxy resin with a thickness of about 5 μm is evenly coated on both sides of the substrate body 3 that are in contact with the current collector, and then two single-sided coated pole pieces 4 are attached to the upper and lower surfaces of the substrate body 3, ensuring that the two measurement optical fibers are arranged in parallel in the groove 7, and after curing at 80°C for another 30 minutes, left to stand for 24 hours, forming the measurement substrate 1. It is particularly noted that the first measurement optical fiber 5 for measuring temperature has a protective sleeve, and the part of the second measurement optical fiber 6 for measuring temperature and strain in the measurement substrate 1 is a bare optical fiber.

[0068] Example Five

[0069] The present embodiment provides a method for manufacturing a lithium ion battery of Example One. The method for manufacturing a lithium ion battery of the present embodiment can be used to manufacture a soft-packaged battery with stacked pole pieces, comprising the following steps:

[0070] An NCM523 positive electrode combined with a graphite negative electrode is used to prepare a 1 Ah capacity lithium ion battery through a stacking process.

[0071] The capacity of the lithium ion battery is determined according to the requirements, and the number of positive and negative pole pieces is determined. Taking a battery capacity of 1 Ah as an example, the number of positive pole pieces is 9, and the number of negative pole pieces is 10. The positive pole pieces and the negative pole pieces are separated by a separator. The two-dimensional size of the electrode of the lithium ion battery is determined to be 45 mm x 58 mm according to the size of the battery cell in the soft-packaged battery and the subsequent battery management requirements.

[0072] A Z-shaped stacking process is used, and the measurement substrate 1 is stacked and assembled with other pole pieces. It is particularly noted that in the present embodiment, the measurement substrate 1 is assembled as a negative electrode, maintaining the assembly mode of the positive and negative pole pieces in cross-stacking. After the cell stacking is completed, the cell is fixed with a fixing tape.

[0073] Then the cell is placed in an aluminum-plastic film shell, and the two measurement optical fibers are led out from the opposite side of the battery tab. The tab side and the tab below of the cell are sealed with a heat sealer. After the two measurement optical fibers are sealed, they are led out to ensure the sealing performance of the battery. The length of the aluminum-plastic film seal at the bottom of the soft-packaged battery is not less than 6 mm.

[0074] Drying in a high-temperature vacuum box for 18 hours, and after cooling, injecting electrolyte (1M LiPF6 in EC: DMC: DEC mixed solvent, EC: DMC: DEC volume ratio 1:1:1) matching the capacity of the cell into the soft-packaged battery packaging bag in a vacuum environment.

[0075] After the first vacuumizing and sealing of the above battery, formation and sorting are carried out, and then secondary vacuumizing and sealing are carried out, so that the lithium ion battery with two measuring optical fibers arranged inside is obtained.

[0076] The internal temperature change of the lithium ion battery manufactured by the manufacturing method of the lithium ion battery of the embodiment is shown in detail in Figure 5 , and the internal strain change of the lithium ion battery is shown in detail in Figure 6 .

[0077] Embodiment six

[0078] The internal measurement method of the lithium ion battery of embodiment one is provided in the embodiment, the first measuring optical fiber 5 is used to respond to the temperature signal inside the lithium ion battery, the second measuring optical fiber 6 is used to respond to the temperature and strain signals inside the lithium ion battery, and the wavelength changes of the first measuring optical fiber 5 and the second measuring optical fiber 6 are collected, so as to realize the decoupling of the temperature and strain signals inside the lithium ion battery.

[0079] The differential algorithm is used to process the reflection wavelength drift data of the first measuring optical fiber 5 and the second measuring optical fiber 6, so as to realize the decoupling of the temperature and strain signals inside the lithium ion battery.

[0080] The differential algorithm calculation formula is as follows:

[0081]

[0082] Δε k =(Δλ ε,T -Δλ T ) / S ε

[0083] Wherein, T is the temperature of the lithium ion battery, T0 is the initial temperature of the lithium ion battery, λ T is the wavelength of the first measuring optical fiber 5, is the initial wavelength of the first measuring optical fiber 5; Δε k is the strain of the lithium ion battery, Δλ ε,T is the wavelength change of the second measuring optical fiber 6, Δλ T is the wavelength change of the first measuring optical fiber 5; S T is the temperature sensitivity coefficient, S ε is the strain sensitivity coefficient, S T and S ε are obtained through laboratory calibration.

[0084] The internal measurement method of the lithium ion battery of the embodiment effectively eliminates the cross interference of the temperature and strain signals, and improves the accuracy of the internal measurement result of the lithium ion battery.

[0085] The first measurement optical fiber 5 and the second measurement optical fiber 6 of the present application both adopt Bragg fiber grating (FBG) technology, a plurality of equidistant Bragg gratings are etched in the optical fiber photosensitive region, and each grating reflects incident light at the center wavelength. When the optical fiber is subjected to temperature action, the refractive index and the grating period change synchronously, causing the reflection center wavelength to drift; when the optical fiber is subjected to strain, only the period changes due to mechanical stretching or compression, also causing the wavelength to drift.

[0086] The present application obtains the temperature sensitivity coefficient of the first measurement optical fiber 5 and the second measurement optical fiber 6 and the strain sensitivity coefficient of the second measurement optical fiber 6 through laboratory calibration, and in actual monitoring, the difference between the wavelength changes of the two measurement optical fibers is used to realize accurate decoupling and separation of the temperature and strain signals, and the change values of the battery temperature and strain are obtained.

[0087] It should be explained here that the laboratory calibration method is a common means for those skilled in the art, which will not be described here.

[0088] Embodiment Seven

[0089] The present embodiment provides an electronic device comprising the lithium ion battery of embodiment one, and the electronic device includes but is not limited to new energy vehicles, energy storage systems, and portable electronic devices.

[0090] The present application applies specific examples to illustrate the principles and implementation modes of the present application, and the above embodiment is only used to help understand the method of the present application and its core idea; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In summary, the content of the present application should not be understood as a limitation of the present application.

Claims

1. A lithium-ion battery, characterized in that: include: A battery cell, the battery cell comprising a measurement substrate, the measurement substrate comprising a substrate body and a pole piece disposed on one side of the substrate body, the substrate body being connected to a current collector side of the pole piece; a measurement assembly, the measurement assembly comprising a first measurement optical fiber and a second measurement optical fiber, the first measurement optical fiber being connected to the measurement substrate and being capable of responding to a temperature signal; The second measuring optical fiber is connected to the current collector side of the pole piece close to the first measuring optical fiber, the second measuring optical fiber is capable of responding to temperature and strain signals, and the second measuring optical fiber is arranged parallel to the first measuring optical fiber; A shell encapsulates the battery core, and the first measuring optical fiber and the second measuring optical fiber can be led out of the shell.

2. The lithium-ion battery according to claim 1, wherein: The base body has a groove capable of accommodating the first measuring optical fiber and the second measuring optical fiber, and the groove is a U-shaped groove with an opening facing the direction of the second measuring optical fiber.

3. The lithium-ion battery according to claim 1, wherein: The first measuring optical fiber is covered with a protective sleeve, and the protective sleeve is bonded to the base body. The second measuring optical fiber is bonded to the current collector side of the pole piece.

4. The lithium-ion battery according to claim 1, wherein: The base body is made of polylactic acid, high temperature resistant resin or ceramic material.

5. The lithium-ion battery according to any one of claims 1 to 4, characterized in that: The first measuring optical fiber and the second measuring optical fiber can both be connected to an external optical fiber wavelength demodulator; The optical fiber wavelength demodulator can also be connected to an electronic recording device.

6. A method for manufacturing a lithium-ion battery according to any one of claims 1 to 5, characterized in that: The steps include: Step 1: Fix the first measuring optical fiber on the base body as a temperature measuring optical fiber, and fix the second measuring optical fiber on the current collector side of the pole piece close to the first measuring optical fiber. The second measuring optical fiber serves as a composite optical fiber, and the current collector side of the pole piece is connected to the base body; Step 2: Encapsulate the battery core using the housing, and lead the first measuring optical fiber and the second measuring optical fiber out of the housing.

7. A method for measuring the internal structure of a lithium-ion battery according to any one of claims 1 to 5, characterized in that: The first measuring optical fiber is used to respond to the temperature signal inside the lithium-ion battery, and the second measuring optical fiber is used to respond to the temperature and strain signals inside the lithium-ion battery. The wavelength changes of the first measuring optical fiber and the second measuring optical fiber are collected to achieve decoupling of the temperature and strain signals inside the lithium-ion battery.

8. The internal measurement method of a lithium-ion battery according to claim 7, characterized in that: A differential algorithm is used to process the reflection wavelength drift data of the first measuring optical fiber and the second measuring optical fiber to achieve decoupling of the temperature and strain signals inside the lithium-ion battery.

9. The lithium-ion battery according to claim 8, characterized in that The calculation formula of the differential algorithm is: T=T0+(λ T -λ T0 ) / S T No k =(Dl ε,T -Dl T ) / S ε Wherein, T is the temperature of the lithium-ion battery, T0 is the initial temperature of the lithium-ion battery, λ T is the wavelength of the first measuring fiber, is the initial wavelength of the first measurement optical fiber; Δε k is the strain of the lithium-ion battery, Δλ ε,T is the wavelength change of the second measuring fiber, Δλ T S is the wavelength change of the first measuring optical fiber; T is the temperature sensitivity coefficient, S ε is the strain sensitivity coefficient, S T and S ε Obtained through laboratory calibration.

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