Lithium ion battery and method for determining deterioration of lithium ion battery

Abstract

The invention relates to a lithium ion battery and a deterioration determination method of the lithium ion battery. A lithium ion battery having a cell in which a positive electrode current collector, a positive electrode active material layer, a separator, a negative electrode active material layer, and a negative electrode current collector are laminated in this order, the lithium ion battery being characterized by having a frame member disposed between the positive electrode current collector and the negative electrode current collector, and a frame member that seals the positive electrode active material layer, the separator, and the negative electrode active material layer, and in which an electronic component that detects the state in the single battery is disposed.

Description

[0001] This application is a divisional application of the following application:

[0002] Invention name: Lithium-ion battery and method for determining deterioration of lithium-ion battery Application date: March 19, 2020 Application number: 202080022669.4 Technical Field

[0003] The invention relates to a lithium ion battery and a method for determining degradation of the lithium ion battery. Background Art

[0004] Lithium-ion (secondary) batteries have been widely used in various applications in recent years as high-capacity, small and light secondary batteries.

[0005] As a lithium ion battery, Patent Document 1 discloses a lithium ion battery having a single cell including an electrolyte solution and including a positive electrode collector, a positive electrode active material layer, a separator, a negative electrode active material layer, and a negative electrode collector stacked in this order.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2018-125213 Summary of the invention

[0009] Problems to be solved by the invention

[0010] Lithium-ion batteries may experience local malfunctions during use, causing their functionality to drop dramatically.

[0011] In such a case, it is not easy to check which part of the lithium-ion battery has failed, so the battery that has failed is often not reused but the battery itself is replaced.

[0012] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a lithium ion battery having a structure suitable for investigating the state inside the lithium ion battery and identifying a location where a malfunction has occurred.

[0013] Solutions for solving problems

[0014] The present invention is a lithium-ion battery having a single cell formed by sequentially stacking a positive electrode collector, a positive electrode active material layer, a separator, a negative electrode active material layer and a negative electrode collector, wherein the lithium-ion battery is characterized in that it has a frame member disposed between the positive electrode collector and the negative electrode collector to seal the positive electrode active material layer, the separator and the negative electrode active material layer, and an electronic component for detecting the state in the single cell is disposed in the frame member;

[0015] The present invention is a method for determining degradation of a lithium-ion battery, which uses the above-mentioned lithium-ion battery. The method for determining degradation of a lithium-ion battery is characterized in that the above-mentioned electronic component arranged in the above-mentioned frame member is a sensor for measuring the potential change during charging, and the potential change and the time required during charging are monitored by the above-mentioned sensor. When the potential rises in a shorter time than the normal state, it is determined that the part in the single battery measured by the sensor has deteriorated;

[0016] The present invention is a method for determining degradation of a lithium-ion battery, which uses the above-mentioned lithium-ion battery. The method for determining degradation of a lithium-ion battery is characterized in that electronic components are respectively arranged at multiple locations within a frame member arranged on the periphery of the above-mentioned single cell. The above-mentioned electronic components are sensors for measuring potential, which detect potential deviations at different locations within the single cell. When the potential deviation exceeds a specified value, it is determined that the single cell has degraded.

[0017] Effects of the Invention

[0018] According to the present invention, by arranging electronic components in the frame member of the unit cell, the state inside the unit cell can be detected, and as a result, the location where a malfunction occurs in the lithium ion battery can be identified. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a partially cutaway perspective view schematically showing an example of the configuration of a lithium-ion battery as a unit cell.

[0020] Figure 2 It is a cross-sectional view schematically showing a state where electronic components are arranged in a frame member.

[0021] Figure 3 This is a partially cutaway perspective view schematically showing another example of the structure of a lithium-ion battery as a unit cell.

[0022] Figure 4 It is a cross-sectional view schematically showing a state where a light emitting element is embedded and arranged in a frame member.

[0023] Figure 5 It is schematically shown from above. Figure 1 The shown figure is a plan view of a lithium-ion battery with the negative electrode current collector removed.

[0024] Figure 6 This is a plan view schematically showing a lithium ion battery in which a wiring substrate is provided in a frame member, with a negative electrode current collector removed, as viewed from above.

[0025] Figure 7 It is a cross-sectional view schematically showing an example of a laminated battery.

[0026] Figure 8 This is a cross-sectional view schematically showing an example of a state in which a light emitting element is embedded and arranged in a frame member of a unit cell constituting a laminate battery.

[0027] Fig. 9 It is a cross-sectional view schematically showing another example of a state in which a light emitting element is embedded and arranged in a frame member of a unit cell constituting a laminate battery. DETAILED DESCRIPTION

[0028] Hereinafter, the present invention will be described in detail.

[0029] In addition, in this specification, when describing a lithium ion battery, the concept is adopted to also include a lithium ion secondary battery.

[0030] The lithium-ion battery of the present invention is a lithium-ion battery having a single cell formed by sequentially stacking a positive electrode collector, a positive electrode active material layer, a separator, a negative electrode active material layer and a negative electrode collector, and is characterized in that it has a frame member arranged between the above-mentioned positive electrode collector and the above-mentioned negative electrode collector, sealing the above-mentioned positive electrode active material layer, the above-mentioned separator and the above-mentioned negative electrode active material layer, and an electronic component for detecting the state inside the single cell is arranged in the above-mentioned frame member.

[0031] Figure 1 FIG. 1 is a partially cutaway perspective view schematically showing an example of the structure of a lithium-ion battery as a single cell. Figure 1 In the figure, the frame member is cut away and shown at a portion where no electronic components are arranged.

[0032] Figure 1 The single cell 1 as a lithium ion battery shown is composed of a positive electrode 2 and a negative electrode 3 stacked with a separator 4. The positive electrode 2 has a positive electrode active material layer 5 formed on the surface of a positive electrode collector 7 in a substantially rectangular flat plate shape, and the negative electrode 3 has a negative electrode active material layer 6 formed on the surface of a negative electrode collector 9 in a substantially rectangular flat plate shape. The separator 4 is also substantially flat, and the whole is formed in a substantially rectangular flat plate shape. The positive electrode and the negative electrode function as the positive electrode and the negative electrode of the lithium ion battery.

[0033] The unit cell 1 includes a frame member 8 that is disposed between a positive electrode current collector 7 and a negative electrode current collector 9 and seals the positive electrode active material layer 5 , the separator 4 , and the negative electrode active material layer 6 .

[0034] exist Figure 1 In the illustrated unit battery 1 , the frame member 8 is an annular frame member and fixes the peripheral edge of the separator 4 between the positive electrode current collector 7 and the negative electrode current collector 9 .

[0035] exist Figure 1 In FIG. 1 , a portion of a single battery is shown through which the electronic component 10 is arranged in the frame member 8 .

[0036] The positive electrode current collector 7 and the negative electrode current collector 9 are positioned to face each other at a predetermined interval by the frame member 8 , and the separator 4 , the positive electrode active material layer 5 , and the negative electrode active material layer 6 are also positioned to face each other at a predetermined interval by the frame member 8 .

[0037] The gap between the positive electrode collector 7 and the separator 4 and the gap between the negative electrode collector 9 and the separator 4 are adjusted according to the capacity of the lithium ion battery, and the positional relationship between the positive electrode collector 7, the negative electrode collector 9 and the separator 4 is determined so as to obtain the necessary gap.

[0038] In the lithium ion battery of the present invention, the electronic component for detecting the state inside the single cell is arranged inside the frame member.

[0039] In conventional lithium-ion batteries, electronic components are not disposed in the frame member, and the location for disposing electronic components is only considered to be the outside of the single battery.

[0040] In contrast, the lithium ion battery of the present invention can detect the state of the single cell by arranging the electronic components in the frame member. By arranging the electronic components in the frame member, it is not necessary to set up a space for arranging the electronic components outside the single cell, and the overall space of the lithium ion battery can be saved.

[0041] Furthermore, by arranging electronic components in the single cell, the state of a position close to the single cell can be detected, so that when a defective portion occurs in the single cell, the accuracy of identifying the position where the defect occurs can be improved.

[0042] Next, the electronic components arranged in the frame member will be described.

[0043] Figure 2 It is a cross-sectional view schematically showing a state where electronic components are arranged in a frame member.

[0044] Figure 2 It is also equivalent to Figure 1 A-A line cross-sectional view.

[0045] Figure 2 The electronic component 10 is shown to be arranged in the frame member 8 .

[0046] The material constituting the frame member 8 is not particularly limited as long as it is a material that is durable to the electrolyte, but is preferably a polymer material, and more preferably a thermosetting polymer material. Specifically, epoxy resins, polyolefin resins, polyester resins, polyurethane resins, and polyvinylidene fluoride resins can be cited, and epoxy resins are preferred from the perspective of high durability and easy handling.

[0047] The electronic component 10 is an electronic component for detecting the state inside the single battery.

[0048] For example, a sensor that measures the temperature, voltage, current, or acoustic emission of a predetermined portion in a single cell is preferred.

[0049] Furthermore, it is preferable that the electronic component can wirelessly output a signal indicating the state inside the cell to an external part of the cell.

[0050] When the electronic component is a sensor, it can detect the state inside the single cell. When the electronic component is an electronic component capable of wireless output, it can wirelessly output a signal representing the detected state and receive the measurement result outside the battery, so that the state inside the single cell can be known without disassembling the single cell.

[0051] By measuring the temperature, voltage or current in the single cell, it is possible to detect a local temperature rise, a current value increase, a voltage drop, etc. caused when a malfunction such as a short circuit occurs in part of the single cell.

[0052] In addition, by measuring acoustic emissions, it is possible to detect whether damage or deformation has occurred inside the battery.

[0053] As electronic components, passive elements and active elements can be used.

[0054] As these elements, any elements such as capacitors, inductors, resistors, transistors, diodes, ICs (Integrated Circuits), and LSIs (Large-Scaled Integrations) can be used.

[0055] In addition, in the case of electronic components capable of wireless output, they may be components such as antennas, filters, amplifiers, oscillators, etc., or they may be wireless communication modules in which these components are modularized, or they may be sensor-integrated modules.

[0056] Furthermore, a switch may be provided for switching between detection of the state in the cell and non-detection using an electronic component disposed in the frame member, so that the switch is switched to detect the state in the cell when a signal from the outside is provided.

[0057] By setting the detection of the state in the single cell only when a signal from the outside is supplied, power consumption by the electronic components can be suppressed.

[0058] Furthermore, in the case of the above configuration, it is preferable that the electronic component includes an antenna element for receiving a signal from the outside.

[0059] Examples of the external signal include a signal that instructs the detection of the state inside the cell and a signal that instructs the detection of the state inside the cell to be stopped.

[0060] Preferably, the electronic component is electrically connected to the negative electrode current collector and the positive electrode current collector, and is formed so as to be able to receive power supply from the lithium ion battery.

[0061] When the electronic component is electrically connected to the negative electrode collector and the positive electrode collector, it can be operated by receiving power from the lithium ion battery. Since it is not necessary to provide a power supply and wiring for operating the electronic component, a simple structure can be adopted.

[0062] When the electronic component is electrically connected to the negative electrode collector and the positive electrode collector, the negative electrode collector and the positive electrode collector are preferably resin collectors, and the negative electrode collector and the positive electrode collector are directly bonded and electrically connected to the electronic component.

[0063] When a resin collector is used, the resin collector is brought into contact with an electrode of an electronic component, and the resin collector is heated to soften the resin, thereby enabling the resin collector to be directly bonded to the electronic component. In other words, by using a resin collector, electrical connection can be made between the collector and the electronic component without using other bonding materials such as solder.

[0064] Figure 2 It is shown that the external electrodes of the electronic component 10 disposed in the frame member 8 are in contact with the positive electrode collector 7 and the negative electrode collector 9. That is, the electronic component 10 is electrically connected to the positive electrode collector 7 and the negative electrode collector 9.

[0065] Furthermore, it is preferable that a through hole for arranging the electronic component is provided in the frame member, the electronic component is arranged in the through hole, and the thickness of the frame member is substantially equal to the height of the electronic component.

[0066] When the electronic components are arranged in the through holes, it is easy to arrange the electronic components in the frame member. By making the thickness of the frame member roughly equal to the height of the electronic components, the electronic components can be brought into contact with the positive electrode collector and the negative electrode collector, thereby electrically connecting the electronic components to the positive electrode collector and the negative electrode collector.

[0067] exist Figure 2, a state is shown in which a through hole 18 is provided in the frame member 8 and the electronic component 10 is arranged in the through hole 18. In addition, the thickness of the frame member is substantially equal to the height of the electronic component.

[0068] Furthermore, the electronic component disposed in the frame member may be a light emitting element that outputs an optical signal.

[0069] When the light emitting element is disposed in the frame member, it is preferable that the light emitting element is embedded in the frame member so as to be exposed on the side surface of the frame member so that light from the light emitting element is directed to the outside of the single battery.

[0070] According to this aspect, a signal indicating the state inside the cell can be wirelessly output to the outside of the cell in the form of an optical signal.

[0071] Figure 3 This is a partially cutaway perspective view schematically showing another example of the structure of a lithium-ion battery as a unit cell.

[0072] Figure 4 It is a cross-sectional view schematically showing a state where a light emitting element is embedded and arranged in a frame member. Figure 4 It is also equivalent to Figure 3 BB line cross-sectional view.

[0073] exist Figure 3 and Figure 4 In the illustrated unit battery 31 , the light emitting element 30 is embedded in the frame member 8 in a manner exposed at the side surface of the frame member 8 .

[0074] The light emitting element 30 converts the electric signal obtained from the unit cell 31 into an optical signal.

[0075] For example, by measuring the voltage between the positive electrode collector 7 and the negative electrode collector 9 in the single cell 31 and emitting light in a light signal pattern corresponding to the voltage, the voltage of the single cell can be detected and wirelessly output to the outside of the single cell in the form of a light signal. In order to measure the voltage, a light-emitting substrate may be provided to make the light-emitting element emit light in a light signal pattern corresponding to the voltage.

[0076] Preferably, in addition to the light-emitting element 30, the light-emitting substrate is also provided with: a voltage measuring terminal for measuring the voltage between the positive electrode collector and the negative electrode collector; and a control element for controlling the light-emitting element 30 to emit light in a specified light signal mode according to the voltage measured by the voltage measuring terminal.

[0077] Preferably, the light emitting substrate is electrically connected to the negative electrode current collector and the positive electrode current collector so that the light emitting element and the control element can receive power from the single cell.

[0078] Here, when the control element of the light-emitting substrate is short-circuited, current may continue to flow through the light-emitting element, and the light-emitting element may continue to emit light. If there is a light-emitting element that continues to emit light, it is completely impossible to distinguish signals from other light-emitting elements, which is a problem.

[0079] In anticipation of such a situation, an element (fuse) for interrupting current may be provided for the purpose of suppressing transmission of an abnormal signal when a failure such as a short circuit occurs in a control element.

[0080] When the resistance of the fuse is high and the light-emitting voltage of the light-emitting element is high, the light-emitting element cannot emit light even in normal conditions. Therefore, by adjusting the specifications of the fuse and the light-emitting element respectively, the light-emitting element can emit light appropriately under normal conditions, and the current to the light-emitting element is cut off under abnormal conditions to suppress the transmission of abnormal signals.

[0081] Examples of the light signal pattern corresponding to voltage include a pattern in which the light emission is switched on / off with a narrower pulse interval as the voltage measured by the voltage measuring terminal increases, and a pattern in which the light emission time per unit time increases.

[0082] In addition, it is preferable that the optical signal pattern is designed to be decodable by software. Specifically, regarding p determined by the following equation (1), it is preferable that p is 1 or more, more preferable that p is 1.5 or more, and particularly preferable that p is 1.75 or more.

[0083] p = log 10 {Cycle / (Pulse length from the start to the end of the longest pulse × the number of stacked single cells)}(1)

[0084] Furthermore, the light emitted from the light emitting element may have two or more colors. In this case, two or more light emitting elements emitting light of different colors (emitting light of different wavelengths) are used.

[0085] When the colors of light emitted from the light emitting elements are set to two or more colors, it is necessary to provide two or more light receiving elements corresponding to the number of colors of the light emitting elements.

[0086] By setting the color of light emitted from the light emitting element to two or more colors, it is possible to easily separate the specific signal. The specific signal means a signal output when an abnormality (abnormally high temperature, abnormally high voltage) occurs in the battery.

[0087] For example, by setting the color of light output for a normal signal for measuring a single cell voltage to be different from the color of light output when a battery abnormality (abnormally high temperature, abnormally high voltage) occurs, important information (abnormal status information) can be accurately transmitted and received without interfering with the signal.

[0088] Setting the color of light to two or more colors means separating the wavelengths of two or more lights to be transmitted and received.

[0089] For example, when two colors of wavelength A and wavelength B are used for communication, it is sufficient to prevent a light emitting element for emitting light of wavelength A (B) from emitting light of wavelength B (A) with an intensity exceeding a certain level.

[0090] Specifically, the wavelength separation of two or more lights can be determined using the following index: the intensity of the light emitting element for emitting light of wavelength A at wavelength B is 1 / n of the intensity of wavelength A. The value of n can be arbitrarily determined according to the wavelengths of the two or more lights, the specifications of the light emitting element and the light receiving element.

[0091] In the above description, an example of measuring the voltage of a single cell and outputting an optical signal pattern corresponding to the voltage is described, but characteristics other than voltage may be measured as characteristics of the single cell. For example, the temperature of the single cell may be measured and an optical signal pattern corresponding to the temperature may be output.

[0092] The optical signal pattern output to the outside of the single cell is received by a light receiving element (not shown) provided outside the single cell and insulated from the single cell. By using the light receiving element to reversely convert the optical signal into an electrical signal, an electrical signal indicating the state inside the single cell can be obtained (the same mechanism as an optical coupler).

[0093] Examples of the light-emitting element include light-emitting diodes, and examples of the light-receiving element include phototransistors.

[0094] The light emitting element and the light receiving element are in a wireless state and electrically insulated, which is preferable from the viewpoint of safety. For example, when an abnormal voltage is generated in one of the circuits inside the single cell or outside the single cell (such as a pulsed high voltage caused by the on / off of a switch), when the voltage is transmitted to the other side, the pair of circuits may be damaged. If they are in an electrically insulated state, damage to them can be avoided, which is preferable.

[0095] In the lithium ion battery of the present invention, preferably, electronic components are disposed at a plurality of locations within a frame member provided on the periphery of the unit cell, respectively, so that the states of different locations within the unit cell can be detected individually.

[0096] Figure 5 It is schematically shown from above. Figure 1 The shown figure is a plan view of a lithium-ion battery with the negative electrode current collector removed.

[0097] Figure 5It is shown that electronic components 10 are provided at six locations inside the frame member 8 .

[0098] The index indicating the state of the cell is detected individually for each of the electronic components 10 provided at the six locations. When an abnormal value is found only in the index obtained from a specific electronic component, it can be estimated that a failure has occurred near the electronic component.

[0099] That is, the cause of the failure in the single battery can be easily identified.

[0100] The number of electronic components provided in the frame member of the unit cell is not particularly limited, and can be arbitrarily set in consideration of the size of the unit cell, the size of the frame member, the size of the electronic components, and the like.

[0101] Furthermore, when electronic components are provided at a plurality of locations within the frame member, the electronic components may all be of the same type or may be a combination of different electronic components.

[0102] In the lithium ion battery of the present invention, the area of ​​the single cell when viewed from above is Figure 5 The area of ​​the inner side of the frame member 8, that is, the area of ​​the main surface of the negative electrode active material layer and the positive electrode active material layer, is determined. This area can be called the effective area of ​​the single cell, and it can be said that the lithium ion battery of the present invention is a battery with a larger battery capacity as the area increases.

[0103] As the area of ​​a single cell in plan view increases, the characteristics inside the single cell are more likely to vary. Therefore, it is particularly effective to arrange electronic components at multiple locations within a frame member provided around the outer periphery of the single cell and individually detect indicators indicating the state inside the single cell.

[0104] For example, it is preferable that the area of ​​the single cell in a plan view is 600 cm 2 above.

[0105] In addition, as for the relationship between the area of ​​the single cell in plan view and the number of electronic components to be arranged, it is preferable that the area of ​​the single cell in plan view is 100 cm 2 One to two electronic components are arranged on the area of ​​the single cell when viewed from above.

[0106] In the lithium ion battery of the present invention, preferably, a wiring substrate is provided in the frame member, and the electronic component is mounted on the wiring substrate.

[0107] Furthermore, it is preferable that other electronic components for controlling the current and / or voltage supplied to the electronic components are mounted on the wiring board.

[0108] By providing a wiring board on the frame member and mounting electronic components on the wiring board, a plurality of functions can be combined to perform various measurements and controls.

[0109] In addition, the preferred current and / or voltage differs according to the specifications of each electronic component, and the current and / or voltage directly supplied from the lithium-ion battery may not be suitable for the specifications of the electronic component. In such a case, by mounting other electronic components for controlling the current and / or voltage supplied to the electronic component on the wiring substrate, various electronic components can be used.

[0110] Figure 6 This is a plan view schematically showing a lithium ion battery in which a wiring substrate is provided in a frame member, with a negative electrode current collector removed, as viewed from above.

[0111] exist Figure 6 In the illustrated unit battery 11 , a wiring substrate 21 is provided on the frame member 8 , and the electronic component 20 is mounted on the wiring substrate 21 .

[0112] Figure 6 As the electronic component 20 , an electronic component assumed to be an amplifier, an IC, or the like is depicted, and as the other electronic component 22 for controlling current and / or voltage, an electronic component assumed to be a chip resistor is depicted.

[0113] The types of electronic components actually mounted on the wiring substrate 21 are not limited to these. In addition, when a module composed of a plurality of electronic components includes a wiring substrate, setting the module on a frame member is also included in one embodiment of setting the wiring substrate on a frame member.

[0114] Hereinafter, preferred embodiments of the components constituting the unit cell will be described.

[0115] The positive electrode active material layer contains a positive electrode active material.

[0116] As the positive electrode active material, composite oxides of lithium and transition metals {composite oxides containing one transition metal (such as LiCoO2, LiNiO2, LiAlMnO4, LiMnO2, and LiMn2O4), composite oxides containing two transition metal elements (such as LiFeMnO4, LiNi 1－x Co x O2、LiMn 1－y Co y O2、LiNi 1 / 3 Co 1 / 3 Al 1 / 3 O2 and LiNi 0.8 Co 0.15 Al 0.05 O2) and a composite oxide of three or more metal elements [e.g., LiM a M' b M” cO2 (M, M' and M" are different transition metal elements, satisfying a + b + c = 1. For example, LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2) etc.], lithium-containing transition metal phosphates (for example, LiFePO4, LiCoPO4, LiMnPO4 and LiNiPO4), transition metal oxides (for example, MnO2 and V2O5), transition metal sulfides (for example, MoS2 and TiS2) and conductive polymers (for example, polyaniline, polypyrrole, polythiophene, polyacetylene and polyparaphenylene and polyvinylcarbazole), etc., and two or more thereof may be used at the same time.

[0117] It should be noted that the lithium-containing transition metal phosphate may be a substance obtained by replacing a part of the transition metal site with other transition metals.

[0118] The positive electrode active material is preferably a coated positive electrode active material coated with a conductive auxiliary agent and a coating resin.

[0119] When the periphery of the positive electrode active material is covered with the covering resin, the volume change of the electrode can be alleviated and the expansion of the electrode can be suppressed.

[0120] Examples of the conductive aid include metal conductive aids [aluminum, stainless steel (SUS), silver, gold, copper, titanium, etc.], carbon conductive aids [graphite and carbon black (acetylene black, Ketjen Black, furnace black, channel black, thermal lamp black, etc.)], and mixtures thereof.

[0121] These conductive additives may be used alone or in combination of two or more. In addition, alloys or metal oxides thereof may also be used.

[0122] In particular, from the viewpoint of electrical stability, more preferred are aluminum, stainless steel, silver, gold, copper, titanium, carbon-based conductive aids and mixtures thereof, further preferred are silver, gold, aluminum, stainless steel and carbon-based conductive aids, and particularly preferred are carbon-based conductive aids.

[0123] Furthermore, as these conductive aids, those obtained by coating a conductive material (preferably a metal conductive aid among the above conductive aids) around a particulate ceramic material or a resin material by electroplating or the like may be used.

[0124] The shape (form) of the conductive additive is not limited to the particle form, and may be forms other than the particle form, and may be forms that are put into practical use as so-called filler-based conductive additives such as carbon nanofibers and carbon nanotubes.

[0125] The ratio of the covering resin to the conductive aid is not particularly limited, but from the perspective of the internal resistance of the battery, the weight ratio of the covering resin (resin solid content weight): conductive aid is preferably 1:0.01 to 1:50, and more preferably 1:0.2 to 1:3.0.

[0126] As the covering resin, a substance described in Japanese Patent Application Laid-Open No. 2017-054703 as a resin for covering an active material for a non-aqueous secondary battery can be preferably used.

[0127] Furthermore, the positive electrode active material layer may contain a conductive auxiliary agent in addition to the conductive auxiliary agent covering the positive electrode active material.

[0128] As the conductive auxiliary agent, the same conductive auxiliary agent as that contained in the above-mentioned coated positive electrode active material can be used appropriately.

[0129] Preferably, the positive electrode active material layer is a non-bonded body including the positive electrode active material and not including a binding material for binding the positive electrode active materials together.

[0130] Here, the term “non-bound body” means that the positive electrode active materials are not bonded to each other, and “bonded” means that the positive electrode active materials are irreversibly fixed to each other.

[0131] The positive electrode active material layer may contain a binding resin.

[0132] As the binder resin, for example, a resin obtained by mixing a small amount of an organic solvent with a nonaqueous secondary battery active material coating resin described in JP-A-2017-054703 and adjusting the glass transition temperature to room temperature or below, and a resin described as a binder in JP-A-10-255805 can be preferably used.

[0133] It should be noted that the adhesive resin means a resin that does not solidify even if the solvent component is evaporated and dried and has adhesive properties (the property of bonding by applying a slight pressure without using water, solvent, heat, etc.). On the other hand, the solution-dried electrode binder used as a binding material means a substance that is dried and solidified by evaporating the solvent component to firmly bond and fix the active materials to each other.

[0134] Therefore, the solution-drying type electrode binder (binder) and the adhesive resin are different materials.

[0135] The thickness of the positive electrode active material layer is not particularly limited, but is preferably 150 to 600 μm, more preferably 200 to 450 μm, from the viewpoint of battery performance.

[0136] The negative electrode active material layer contains a negative electrode active material.

[0137] As the negative electrode active material, known negative electrode active materials for lithium ion batteries can be used, and examples thereof include carbon materials [graphite, non-graphitizable carbon, amorphous carbon, resin sintered bodies (for example, phenolic resins and furan resins, etc., sintered carbonized materials, etc.), cokes (for example, pitch coke, needle coke, and petroleum coke, etc.), and carbon fibers, etc.], silicon materials [silicon, silicon oxide (SiO x ), silicon-carbon composites (substances obtained by covering the surface of carbon particles with silicon and / or silicon carbide, substances obtained by covering the surface of silicon particles or silicon oxide particles with carbon and / or silicon carbide, and silicon carbide, etc.), and silicon alloys (silicon-aluminum alloys, silicon-lithium alloys, silicon-nickel alloys, silicon-iron alloys, silicon-titanium alloys, silicon-manganese alloys, silicon-copper alloys, and silicon-tin alloys, etc.), conductive polymers (for example, polyacetylene and polypyrrole, etc.), metals (tin, aluminum, zirconium, and titanium, etc.), metal oxides (titanium oxide and lithium-titanium oxide, etc.), and metal alloys (for example, lithium-tin alloys, lithium-aluminum alloys, and lithium-aluminum-manganese alloys, etc.), and mixtures thereof with carbon materials, etc.

[0138] Furthermore, the negative electrode active material may be a coated negative electrode active material coated with a conductive auxiliary agent and a coating resin similar to the above-mentioned coated positive electrode active material.

[0139] As the conductive auxiliary agent and the coating resin, the same conductive auxiliary agent and the coating resin as those used to coat the positive electrode active material can be appropriately used.

[0140] The negative electrode active material layer may contain a conductive auxiliary agent in addition to the conductive auxiliary agent coating the negative electrode active material. As the conductive auxiliary agent, the same conductive auxiliary agent as that contained in the above-mentioned conductive auxiliary agent coating the positive electrode active material can be appropriately used.

[0141] Like the positive electrode active material layer, the negative electrode active material layer is preferably a non-adhesive body that does not contain a binding material for binding the negative electrode active materials together. Also, like the positive electrode active material layer, the negative electrode active material layer may contain a binding resin.

[0142] The thickness of the negative electrode active material layer is not particularly limited, but is preferably 150 to 600 μm, more preferably 200 to 450 μm, from the viewpoint of battery performance.

[0143] Examples of materials constituting the positive electrode current collector and the negative electrode current collector (hereinafter collectively referred to as current collectors) include metal materials such as copper, aluminum, titanium, stainless steel, nickel, and alloys thereof, as well as calcined carbon, conductive polymer materials, and conductive glass.

[0144] Among these materials, aluminum is preferred as the positive electrode current collector, and copper is preferred as the negative electrode current collector from the viewpoints of weight reduction, corrosion resistance, and high conductivity.

[0145] Furthermore, the current collector is preferably a resin current collector made of a conductive polymer material.

[0146] The shape of the current collector is not particularly limited, and may be a sheet-shaped current collector made of the above-mentioned material or a stacked layer made of fine particles made of the above-mentioned material.

[0147] The thickness of the current collector is not particularly limited, but is preferably 50 to 500 μm.

[0148] As the conductive polymer material constituting the resin current collector, for example, a conductive polymer material obtained by adding a conductive agent to a conductive polymer or resin as needed can be used.

[0149] As the conductive agent constituting the conductive polymer material, the same conductive agent as that contained in the above-mentioned coated positive electrode active material can be preferably used.

[0150] Examples of the resin constituting the conductive polymer material include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polycycloolefin (PCO), polyethylene terephthalate (PET), polyether nitrile (PEN), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVdF), epoxy resin, silicone resin or a mixture thereof.

[0151] From the viewpoint of electrical stability, polyethylene (PE), polypropylene (PP), polymethylpentene (PMP) and polycycloolefin (PCO) are preferred, and polyethylene (PE), polypropylene (PP) and polymethylpentene (PMP) are more preferred.

[0152] As the separator, there can be listed well-known separators for lithium ion batteries, such as porous films made of polyethylene or polypropylene, laminated films of porous polyethylene film and porous polypropylene, non-woven fabrics made of synthetic fibers (polyester fibers and aramid fibers, etc.) or glass fibers, and materials having ceramic particles such as silica, alumina, and titanium dioxide attached to their surfaces.

[0153] The positive electrode active material layer and the negative electrode active material layer contain an electrolyte solution.

[0154] As the electrolytic solution, a known electrolytic solution containing an electrolyte and a non-aqueous solvent, which is used for production of known lithium ion batteries, can be used.

[0155] As the electrolyte, substances used in known electrolytes can be used, for example, lithium salts of inorganic acids such as LiN(FSO2)2, LiPF6, LiBF4, LiSbF6, LiAsF6 and LiClO4, lithium salts of organic acids such as LiN(CF3SO2)2, LiN(C2F5SO2)2 and LiC(CF3SO2)3, etc. can be listed. Among these, from the viewpoint of battery output and charge and discharge cycle characteristics, imide electrolytes [LiN(FSO2)2, LiN(CF3SO2)2 and LiN(C2F5SO2)2, etc.] and LiPF6 are preferred.

[0156] As the non-aqueous solvent, substances used in known electrolyte solutions can be used, for example, lactone compounds, cyclic or chain carbonates, chain carboxylates, cyclic or chain ethers, phosphates, nitriles, amides, sulfones, cyclopentane sulfones, etc. and mixtures thereof can be used.

[0157] The electrolyte concentration of the electrolytic solution is preferably 1 to 5 mol / L, more preferably 1.5 to 4 mol / L, and even more preferably 2 to 3 mol / L.

[0158] When the electrolyte concentration of the electrolytic solution is less than 1 mol / L, sufficient input / output characteristics of the battery may not be obtained, and when the electrolyte concentration of the electrolytic solution exceeds 5 mol / L, the electrolyte may precipitate.

[0159] The electrolyte concentration of the electrolytic solution can be determined by extracting the electrolytic solution constituting the lithium ion battery electrode or the lithium ion battery without using a solvent or the like and measuring the concentration.

[0160] The lithium ion battery of the present invention may be a laminated battery in which a plurality of unit cells are laminated, and the electronic component disposed in the frame member may be used to individually detect the state of each unit cell constituting the laminated battery.

[0161] Figure 7 It is a cross-sectional view schematically showing an example of a laminated battery.

[0162] Figure 7 shows a stack of four Figure 1 A stacked battery 101 of single cells 1 is shown.

[0163] The stacked battery 101 is stacked in series so that the upper surfaces of the negative electrode current collectors 9 of adjacent unit cells 1 are adjacent to the lower surfaces of the positive electrode current collectors 7 . The stacked battery 101 is housed in a container 120 .

[0164] A positive electrode lead-out portion 107 is provided on the lower surface of the container 120 , and a negative electrode lead-out portion 109 is provided on the upper surface of the container 120 .

[0165] The positive electrode lead-out portion 107 is electrically connected to the positive electrode collector 7 of the lowermost unit cell 1 , and the negative electrode lead-out portion 109 is electrically connected to the negative electrode collector 9 of the uppermost unit cell 1 .

[0166] Electronic components 10 are arranged on the frame members 8 of the unit cells 1 .

[0167] Figure 7 Although the electronic components 10 are shown arranged alternately left and right in the cross-sectional view, the arrangement position of the electronic components of each unit cell may be the same as or different from that of other unit cells constituting the laminated battery.

[0168] Since electronic components are arranged in the frame members of each single cell, the state of each single cell can be detected individually. Therefore, when a malfunction occurs during the use of the laminated battery, it is possible to identify which single cell has the malfunction. Furthermore, if only the single cell with the malfunction is replaced, the laminated battery with the malfunction can be reused while the majority of the laminated battery is effectively used.

[0169] In the laminated battery, the electronic component disposed in the frame member of the unit cell may be a light emitting element that outputs an optical signal.

[0170] In the case where the electronic component disposed in the frame member of the single cell is a light emitting element, the example can be set as shown in FIG. Figure 3 and Figure 4 As explained.

[0171] Furthermore, when a light emitting element is disposed in a frame member of each unit cell constituting a laminate battery, it is preferable to provide an optical waveguide for introducing an optical signal from the light emitting element on a side surface of the laminate battery.

[0172] Furthermore, a container for accommodating the laminated battery and the optical waveguide may be provided, one end of the optical waveguide may be extended outside the container, and an optical signal derived from the end of the optical waveguide extended outside the container may be received by the light receiving unit.

[0173] Figure 8 This is a cross-sectional view schematically showing an example of a state in which a light emitting element is embedded and arranged in a frame member of a unit cell constituting a laminate battery.

[0174] In the composition Figure 8 In the illustrated single cell 31 of the laminated battery 102 , the light emitting element 30 is embedded in the frame member 8 in a manner exposed at the side surface of the frame member 8 .

[0175] An optical waveguide 130 for introducing an optical signal from the light emitting element 30 is provided on a side surface of the laminated battery 102 . An optical signal from each light emitting element 30 of each unit cell 31 is introduced into the optical waveguide 130 .

[0176] The laminated battery 102 and the optical waveguide 130 are housed in the container 120 . However, one end of the optical waveguide 130 is formed to extend to the outside of the container 120 , and the optical signal led out from the one end is received by the light receiving element 141 .

[0177] The light receiving element 141 can obtain an electrical signal indicating the state of the single cell contained in the laminate battery by reversely converting the optical signal into an electrical signal.

[0178] Fig. 9 This is a cross-sectional view schematically showing an example of a state in which a light emitting element is embedded and arranged in a frame member of a unit cell constituting a laminate battery.

[0179] In the composition Fig. 9 In the single cell 31 of the laminate battery 103 shown, the light emitting element 30 is also embedded in the frame member 8 in a form exposed at the side surface of the frame member 8 .

[0180] A light receiving element 142 is provided on the side surface of the laminate cell 103 for each light emitting element 30 .

[0181] Each light receiving element 142 obtains an electrical signal indicating the state of the unit cell contained in the laminate battery by reversely converting the signal into an electrical signal.

[0182] The laminated battery 103 and the light receiving element 142 are housed in the container 120 . However, one end of a wiring 143 connected to the light receiving element 142 is extended to the outside of the container 120 , and an electrical signal is output to the outside of the container 120 by the wiring 143 .

[0183] Even in reference Figure 8 and Fig. 9 In the case of the laminated batteries described above, when the electronic component arranged in the frame member of the unit cell is a light emitting element that outputs an optical signal, the light emitting element and the light receiving element are also in a wireless state. The light emitting element and the light receiving element are electrically insulated, which is preferable from the viewpoint of safety.

[0184] The lithium ion battery of the present invention may be a battery module composed of a plurality of laminated batteries each including a plurality of unit cells, and the state of each laminated battery constituting the battery module may be individually detected by electronic components disposed in a frame member.

[0185] In the case of a battery module in which a plurality of stacked batteries are combined, the electronic components are arranged in the frame member of the single battery, so the state of each single battery can be detected individually. Therefore, when a malfunction occurs during use of the battery module, it is possible to identify which single battery of which stacked battery has the malfunction. Furthermore, if only the single battery having the malfunction is replaced, the malfunctioning battery module can be reused while most of the battery module is effectively used.

[0186] Towards Figure 8 The light receiving element 141 in the stacked battery 102 shown in FIG. Fig. 9 The signal transmitted from the wiring 143 in the laminated battery 103 is processed by a hardware device located outside the laminated battery. The hardware device functions as a part of a battery management system (BMS), and the hardware device and the laminated battery may be separated.

[0187] Generally speaking, the durability of hardware devices is set at about 10 years, but depending on the method of use, laminated batteries can be used for a longer period of time. Therefore, if the laminated battery and the hardware device are separable, when the durability of the hardware device has passed, the laminated battery can be used continuously without disassembling the laminated battery and only the hardware device can be replaced. In this way, the overall life of the battery management system can be extended.

[0188] Next, a method for determining deterioration of a lithium ion battery according to the present invention will be described as an example of a method for using the lithium ion battery according to the present invention.

[0189] In the method for determining deterioration of a lithium-ion battery of the present invention using the lithium-ion battery of the present invention, the electronic component disposed in the frame member is a sensor for measuring a potential change during charging, and the potential change and the time required during charging are monitored by the sensor. When a potential rise occurs in a shorter time than in a normal state, it is determined that a portion of the single cell measured by the sensor has deteriorated.

[0190] In the lithium ion battery of the present invention, when the electronic component disposed in the frame member is a sensor for measuring a potential change during charging, the potential change and the time required for charging at a predetermined location in the single cell can be monitored.

[0191] During charging, the current is kept constant, so if the potential rises quickly, it means that the capacity of the single cell has decreased, that is, the single cell has deteriorated.

[0192] In particular, when the lithium-ion battery of the present invention is a stacked battery, the potential change during charging is monitored for each single cell by electronic components arranged in the frame member. When a single cell with a fast potential rise rate is identified, it can be determined that the single cell is in a state of particularly advanced degradation.

[0193] In addition, when the lithium-ion battery of the present invention is a battery module, electronic components arranged in the frame member are also used to monitor the potential change during charging for each single cell or stacked battery. When a single cell or stacked battery with a fast potential rise rate is identified, it can be determined that the single cell or stacked battery is in a state of particularly progressing degradation.

[0194] For example, when the time during which the potential rise occurs in a normal state is defined as 100%, if the time during which the potential rise occurs becomes 70% or less, it can be determined that the cell is deteriorated.

[0195] Next, a method for determining deterioration of a lithium ion battery according to the present invention will be described as another example of a method for using the lithium ion battery according to the present invention.

[0196] In the method for determining the deterioration of a lithium-ion battery of the present invention using the lithium-ion battery of the present invention, electronic components are respectively arranged at a plurality of locations within a frame member disposed on the periphery of a single cell. The electronic components are sensors for measuring potential, and detect potential deviations at different locations within the single cell. When the potential deviation exceeds a specified value, it is determined that the single cell has deteriorated.

[0197] In the lithium ion battery of the present invention, electronic components are disposed at a plurality of locations within the frame member provided on the periphery of the unit cell. When the electronic components are sensors for measuring potential, potential deviations at different locations within the unit cell can be detected.

[0198] In a battery that has not deteriorated, the potential in one single cell is the same regardless of where in the cell the potential is measured. However, if there is a deviation in the potential detected by each sensor in the single cell, the single cell is considered to be deteriorated.

[0199] Therefore, by providing sensors for measuring potential at a plurality of locations in advance in the frame member of one unit cell and allowing the sensors to detect the potential in the unit cells individually, it is possible to identify a deteriorated unit cell.

[0200] For example, when there is a deviation in the potentials measured at a plurality of locations within a single cell and a measurement point differs by ±0.2 V or more from the average value of the voltage measurement value, it is determined that the single cell has deteriorated.

[0201] In addition, when the lithium-ion battery of the present invention is a stacked battery, the potential of each single cell is monitored by electronic components arranged in the frame member to detect the deviation of the potential of each single cell. When a potential deviation occurs between single cells, it can be determined that a single cell with a different potential than other single cells is in a state of particularly deteriorating development.

[0202] In addition, when the lithium-ion battery of the present invention is a battery module, electronic components arranged in the frame member are also used to monitor the potential changes during charging for each single cell or each stacked battery. When a potential deviation occurs between single cells or stacked batteries, it can be determined that a single cell or stacked battery with a different potential than other single cells or stacked batteries is in a particularly deteriorated state.

[0203] It should be noted that, in the present invention, the configuration of arranging electronic components in the frame member is not limited to the configuration of embedding and arranging electronic components in the frame member as described above. For example, a configuration of accommodating electronic components in a notch (recess) formed on the outer peripheral surface of the frame member may also be adopted, as long as electronic components are arranged in the region where the frame member is arranged (the region of the peripheral portion between the positive electrode collector and the negative electrode collector), and other various configurations may be used.

[0204] Industrial Applicability

[0205] The lithium ion battery of the present invention can detect the state inside the single cell by arranging electronic components in the frame member of the single cell, and as a result, can identify the location where a malfunction occurs in the lithium ion battery.

[0206] Furthermore, when the lithium ion battery of the present invention is used in a stacked battery or a battery module, by replacing only the defective single cell, the defective stacked battery or battery module can be reused while most of the stacked battery or battery module is effectively utilized.

[0207] Description of reference numerals:

[0208] 1, 11, 31: single cell;

[0209] 2: positive electrode;

[0210] 3: negative electrode;

[0211] 4: diaphragm;

[0212] 5: positive electrode active material layer;

[0213] 6: negative electrode active material layer;

[0214] 7: positive electrode collector;

[0215] 8: frame components;

[0216] 9: negative electrode current collector;

[0217] 10, 20: electronic components;

[0218] 18: through hole;

[0219] 21: Wiring substrate;

[0220] 22: Other electronic components;

[0221] 30: light emitting element;

[0222] 101, 102, 103: laminated battery;

[0223] 107: positive electrode lead-out portion;

[0224] 109: negative electrode lead-out portion;

[0225] 120: container;

[0226] 130: Optical waveguide;

[0227] 141, 142: light receiving element;

[0228] 143: Wiring.

Claims

1. A lithium ion battery comprising a single cell in which a positive electrode current collector, a positive electrode active material layer, a separator, a negative electrode active material layer and a negative electrode current collector are stacked in sequence, wherein: The invention comprises: a frame member disposed between the positive electrode current collector and the negative electrode current collector, and sealing the positive electrode active material layer, the separator, and the negative electrode active material layer; Electronic components for detecting the state inside the single battery are arranged in the region where the frame member is arranged.

2. The lithium ion battery according to claim 1, wherein The electronic component is a sensor that measures temperature, voltage, current, or acoustic emission at a predetermined location within the single battery.

3. The lithium ion battery according to claim 1 or 2, wherein: Electronic components are disposed at a plurality of locations within a frame member disposed on the periphery of the single battery. The electronic components individually detect the status of different locations within the single battery.

4. The lithium ion battery according to claim 1 or 2, wherein: The electronic component is electrically connected to the negative electrode current collector and the positive electrode current collector, and receives power from a lithium-ion battery.

5. The lithium ion battery according to claim 4, wherein: The negative electrode current collector and the positive electrode current collector are resin current collectors, and the negative electrode current collector and the positive electrode current collector are directly bonded to the electronic component to be electrically connected.

6. The lithium ion battery according to claim 1 or 2, wherein: The frame member is provided with a through hole for arranging an electronic component, the electronic component is arranged in the through hole, and the thickness of the frame member is substantially equal to the height of the electronic component.

7. The lithium ion battery according to claim 1 or 2, wherein: A wiring board is provided in the frame member, and the electronic component is mounted on the wiring board.

8. The lithium ion battery according to claim 7, wherein: Other electronic components for controlling the current and / or voltage supplied to the electronic components are mounted on the wiring substrate.

9. The lithium ion battery according to claim 1 or 2, wherein: The electronic component wirelessly outputs a signal indicating a state inside the unit battery to the outside of the unit battery.

10. The lithium ion battery according to claim 1 or 2, wherein: The lithium-ion battery is a laminated battery in which a plurality of the above-mentioned single cells are stacked. The state of each of the unit cells constituting the laminate battery is individually detected by the electronic component disposed in the frame member.

11. The lithium ion battery according to claim 1 or 2, wherein: The lithium-ion battery is a battery module composed of a plurality of stacked batteries having a plurality of the single cells stacked on top of each other. The state of each of the laminate batteries constituting the battery module is individually detected by the electronic components arranged in the frame member.

12. The lithium ion battery according to claim 1 or 2, wherein: A switch is provided for switching between detecting the state of the single battery by the electronic component arranged in the frame member and not detecting the state of the single battery, When a signal from the outside is provided, the switch is switched to detect the state inside the single battery.

13. A method for determining degradation of a lithium ion battery, using the lithium ion battery according to claim 1 or 2, wherein the method for determining degradation of a lithium ion battery is characterized in that: The electronic component disposed in the frame member is a sensor for measuring a potential change during charging. The above-mentioned sensor monitors the potential change and required time during charging, and when the potential rises in a shorter time than in a normal state, it is determined that the part in the single cell measured by the sensor has deteriorated.

14. A method for determining degradation of a lithium-ion battery, using the lithium-ion battery according to claim 1 or 2, wherein the method for determining degradation of a lithium-ion battery is characterized in that: Electronic components are disposed at a plurality of locations within a frame member disposed on the periphery of the single battery. The electronic component is a sensor for measuring electric potential, The potential deviation at different locations in the single cell is detected, and when the potential deviation exceeds a predetermined value, it is determined that the single cell has deteriorated.

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