Sensor module and rotating body with sensor
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Filing Date
- 2023-12-25
- Publication Date
- 2026-05-11
AI Technical Summary
Existing sensor modules with rechargeable secondary batteries face challenges when installed on rotating bodies due to deteriorating battery characteristics caused by centrifugal forces, leading to difficulties in maintaining functionality.
The sensor module incorporates a sintered electrode layer for the positive or negative electrode, which retains electrolyte solution effectively, and positions the electrode closer to the central axis to mitigate centrifugal force effects, ensuring stable operation and signal transmission.
The solution maintains battery characteristics and enables stable signal transmission by retaining electrolyte solution and preventing overlap between the antenna and battery, allowing the sensor module to function effectively on rotating bodies.
Abstract
Description
Sensor module and rotating body with sensor
[0001] The present disclosure relates to a sensor module and a rotating body with a sensor.
[0002] Sensors are sometimes installed in facilities to detect changes or abnormalities in the facilities over time. Such sensors can be installed in the facilities as a sensor module that includes a sensor, a battery, and the like mounted on a single circuit board (see, for example, JP 2020-63913 A (Patent Document 1)).
[0003] Japanese Patent Application Laid-Open No. 2020-63913
[0004] In the sensor module described above, a rechargeable secondary battery is sometimes used as the battery. However, when the sensor module is installed in a rotating body, the battery characteristics may deteriorate. As a result, it may become difficult to apply the sensor module to the rotating body.
[0005] Therefore, it is an object of the present disclosure to provide a sensor module that can be applied to a rotating body and a sensor-equipped rotating body that includes the sensor module.
[0006] A sensor module according to the present disclosure includes a wiring board including a first mounting surface and a second mounting surface located on the opposite side of the first mounting surface in a thickness direction, a sensor disposed on the first mounting surface, a wireless communication module disposed on the first mounting surface, the wireless communication module including an antenna and electrically connected to the sensor, and a secondary battery disposed on the second mounting surface and supplying power to the sensor and the wireless communication module. The secondary battery includes a separator, a positive electrode layer and a negative electrode layer disposed on either side of the separator, an electrolyte impregnated in the separator, the positive electrode layer, and the negative electrode layer, and an exterior material that accommodates the separator, the positive electrode layer, the negative electrode layer, and the electrolyte. At least one of the positive electrode layer and the negative electrode layer is a sintered electrode layer that is an electrode layer composed of a sintered body.
[0007] According to the above sensor module, it is possible to provide a sensor module that can be applied to a rotating body.
[0008] FIG. 1 is a schematic perspective view showing the structure of a sensor module. FIG. 2 is a schematic perspective view showing the structure of a sensor module. FIG. 3 is a schematic plan view showing the structure of a sensor module. FIG. 4 is a schematic plan view showing the structure of a sensor module. FIG. 5 is a schematic perspective view showing the structure of a lithium ion secondary battery. FIG. 6 is a schematic cross-sectional view showing the structure of a lithium ion secondary battery. FIG. 7 is a schematic cross-sectional view showing the structure of a lithium ion secondary battery. FIG. 8 is a schematic view showing the structure of a rotating body with a sensor.
[0009] [Overview of the Embodiments] First, embodiments of the present disclosure will be described. The sensor module of the present disclosure includes a wiring substrate including a first mounting surface and a second mounting surface located on the opposite side of the first mounting surface in a thickness direction, a sensor disposed on the first mounting surface, a wireless communication module disposed on the first mounting surface, the wireless communication module including an antenna and electrically connected to the sensor, and a secondary battery disposed on the second mounting surface and supplying power to the sensor and the wireless communication module. The secondary battery includes a separator, a positive electrode layer and a negative electrode layer sandwiched between the separator, an electrolyte impregnated in the separator, the positive electrode layer, and the negative electrode layer, and an exterior material that accommodates the separator, the positive electrode layer, the negative electrode layer, and the electrolyte. At least one of the positive electrode layer and the negative electrode layer is a sintered electrode layer that is an electrode layer composed of a sintered body.
[0010] When a sensor module including a secondary battery is installed on a rotating body, centrifugal force acts on the secondary battery as the rotating body rotates. This centrifugal force causes the electrolyte contained in the secondary battery to become unevenly distributed, resulting in a state in which the electrolyte is not impregnated in part or all of the positive electrode layer and negative electrode layer. As a result, the parts of the positive electrode layer and negative electrode layer that are not impregnated with the electrolyte do not function, and the performance of the secondary battery deteriorates.
[0011] In contrast, in the secondary battery included in the sensor module of the present disclosure, at least one of the positive electrode layer and the negative electrode layer is a sintered electrode layer, which is an electrode layer composed of a sintered body. The sintered body has a structure in which raw material particles are connected to each other by necks. Therefore, the pores within the sintered body have a complex labyrinth-like shape, which provides a high electrolyte retention capacity. As a result, even when the sensor module of the present disclosure is installed on a rotating body and centrifugal force is applied to the secondary battery, the electrolyte is retained in the sintered electrode layer, and deterioration of the secondary battery's characteristics is suppressed. In this way, the sensor module of the present disclosure can provide a sensor module that can be applied to a rotating body.
[0012] In the sensor module, the sintered body constituting the sintered electrode layer may have an average pore diameter of 0.2 μm or more and 5.0 μm or less. By setting the average pore diameter to 0.2 μm or more, the sintered electrode layer can be easily impregnated with the electrolyte. By setting the average pore diameter to 5.0 μm or less, a high retention force for the electrolyte when centrifugal force is applied can be easily ensured.
[0013] In the sensor module, both the positive electrode layer and the negative electrode layer may be sintered electrode layers. With this configuration, regardless of the installation mode of the sensor module, deterioration of the characteristics of the secondary battery due to the action of centrifugal force can be suppressed.
[0014] In the sensor module, the antenna and the secondary battery may be configured not to overlap when viewed perpendicularly to the first mounting surface. This configuration prevents the secondary battery from interfering with the signal transmitted from the antenna. As a result, the wireless communication module can stably transmit the signal.
[0015] In the sensor module, the exterior may contain only one separator, one positive electrode layer, and one negative electrode layer. This configuration makes it easy to reduce the thickness of the secondary battery. As a result, it is easy to reduce the thickness of the sensor module.
[0016] The sensor module may further include a wireless charging module disposed on the first mounting surface and electrically connected to the secondary battery, which facilitates charging of the secondary battery.
[0017] The sensor-equipped rotating body of the present disclosure includes a rotating body rotatable about a central axis, and the sensor module of the present disclosure, which is installed at a position away from the central axis of the rotating body, with the sintered electrode layer being located closer to the central axis than the separator.
[0018] The sensor-equipped rotating body of the present disclosure includes a sensor module having a secondary battery in which at least one of the positive electrode layer and the negative electrode layer is a sintered electrode layer. The sintered electrode layer is positioned closer to the central axis than the separator. When the rotating body rotates, centrifugal force causes the electrolyte to shift from the side closer to the central axis to the side farther from the separator. However, in the sensor-equipped rotating body of the present disclosure, the sintered electrode layer is positioned closer to the central axis than the separator. This suppresses deterioration in the characteristics of the secondary battery. Thus, the sensor-equipped rotating body of the present disclosure can provide a sensor-equipped rotating body in which deterioration in the characteristics of the secondary battery due to rotation is suppressed.
[0019] [Specific Example of Embodiment] Next, specific examples of the sensor module and the sensor-equipped rotating body of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference characters, and their description will not be repeated.
[0020] Figures 1 and 2 are schematic perspective views showing the structure of the sensor module. Figures 1 and 2 are perspective views seen from different viewpoints. Figures 3 and 4 are schematic plan views showing the structure of the sensor module. Figures 3 and 4 are plan views seen from opposite directions in the thickness direction of the sensor module.
[0021] 1 to 4, a sensor module 1, which is one embodiment of the sensor module of the present disclosure, includes a wiring substrate 10, an acceleration sensor 20, a wireless communication module 30, a wireless charging module 40, a plurality of electronic components 51, and a lithium ion secondary battery 60.
[0022] The wiring board 10 includes a base substrate made of an insulating material such as resin, and wiring made of a conductive material such as copper arranged on at least one of the surface and the interior of the base substrate. The wiring board 10 is, for example, a printed wiring board. The wiring board 10 includes a first mounting surface 11 and a second mounting surface 12 located on the opposite side of the first mounting surface 11 in the thickness direction.
[0023] The acceleration sensor 20 is disposed on the first mounting surface 11 of the wiring board 10. The acceleration sensor 20 is electrically connected to the wiring that constitutes the wiring board 10. The acceleration sensor 20 detects acceleration such as vibration and outputs a signal containing information about the detected acceleration. In this embodiment, only one acceleration sensor 20 is disposed on the first mounting surface 11, but multiple acceleration sensors may be disposed. Furthermore, instead of or in addition to the acceleration sensor 20, another sensor, such as a temperature sensor, may be disposed on the first mounting surface 11.
[0024] The wireless communication module 30 is disposed on the first mounting surface 11 of the wiring board 10. The wireless communication module 30 is electrically connected to the wiring that constitutes the wiring board 10. The wireless communication module 30 is electrically connected to the acceleration sensor 20 via the wiring. The wireless communication module 30 includes an antenna 31. The wireless communication module 30 transmits a signal including information such as acceleration detected by a sensor such as the acceleration sensor 20 from the antenna 31 to the outside.
[0025] The wireless charging module 40 is disposed on the first mounting surface 11 of the wiring board 10. The wireless charging module 40 is electrically connected to the wiring that constitutes the wiring board 10. The wireless charging module 40 includes a power receiving coil (not shown). A magnetic field generated by a current flowing through an external power transmitting coil causes a current to flow through the power receiving coil, thereby charging the lithium ion secondary battery 60, which will be described later. Note that the lithium ion secondary battery 60 may be charged, for example, by a microwave method in which a current flowing through an external power transmitting antenna is converted into electromagnetic waves and received by a power receiving antenna.
[0026] The electronic components 51 may be, for example, passive elements, semiconductor elements, etc. Examples of semiconductor elements include transistors, diodes, etc. The electronic components 51 are electrically connected to the wiring that constitutes the wiring board 10.
[0027] The lithium ion secondary battery 60 is disposed on the second mounting surface 12 of the wiring board 10. The lithium ion secondary battery 60 is electrically connected to the wiring constituting the wiring board 10. The lithium ion secondary battery 60 is electrically connected to the wireless charging module 40 via the wiring. The lithium ion secondary battery 60 is charged by a current flowing through the power receiving coil as a result of a current flowing through an external power transmitting coil. The lithium ion secondary battery 60 is electrically connected to the acceleration sensor 20, the wireless communication module 30, and multiple electronic components 51 via the wiring. As a result, the lithium ion secondary battery 60 supplies power to the acceleration sensor 20, the wireless communication module 30, and the like. Referring to FIG. 3 , the antenna 31 and the lithium ion secondary battery 60 are disposed so as not to overlap each other when viewed in a direction perpendicular to the first mounting surface 11.
[0028] Next, the structure of the lithium ion secondary battery 60 will be described. Fig. 5 is a schematic perspective view showing the structure of a lithium ion secondary battery. Figs. 6 and 7 are schematic cross-sectional views showing the structure of a lithium ion secondary battery. Fig. 6 shows a cross section taken along line VI-VI in Fig. 5. Fig. 7 shows a cross section taken along line VII-VII in Fig. 5.
[0029] 5 to 7 , a lithium-ion secondary battery 60 according to the present embodiment includes a pair of exterior films 600, a battery body 620, a positive electrode tab terminal 631, and a negative electrode tab terminal 632. Each exterior film 600 has the same rectangular shape when viewed in the thickness direction. In the pair of exterior films 600, which are exterior materials, first outer edges 601 corresponding to the first short sides of the rectangle, second outer edges 602 corresponding to the first long sides, third outer edges 603 corresponding to the second short sides, and fourth outer edges 604 corresponding to the second long sides are bonded to each other. More specifically, the first outer edges 601 are bonded to each other over the entire area except for portions facing each other across the positive electrode tab terminal 631 and the negative electrode tab terminal 632 (see FIG. 7 ). The second outer edges 602, the third outer edges 603, and the fourth outer edges 604 are bonded to each other over the entire circumferential area. In this embodiment, the outer edges 601 to 604 are joined by fusion. The joining can be achieved by heat fusion. That is, in the pair of exterior films 600, the outer edges 601 to 604 are joined (fused) to each other in a stacked state. Referring to FIG. 6, the pair of exterior films 600 each include an inner surface 600A that is a surface facing each other, and an outer surface 600B that is a main surface opposite to the inner surface 600A. An internal space 600C is formed between the facing inner surfaces 600A of the pair of exterior films 600.
[0030] 6 , the internal space 600C accommodates a battery body 620. The battery body 620 includes a separator film 621 as a separator, a positive electrode layer 622, a negative electrode layer 623, a positive electrode current collector foil 624, a negative electrode current collector foil 625, and an electrolyte 626.
[0031] The separator film 621 is a resin film. Examples of resins that can be used to form the separator film 621 include polyolefin, polyimide, polyester (e.g., polyethylene terephthalate (PET)), and cellulose.
[0032] The positive electrode layer 622 is laminated on a first main surface 621A, which is one of the main surfaces of the separator film 621. The positive electrode layer 622 of this embodiment is a plate-shaped sintered body of lithium composite oxide. That is, the positive electrode layer 622 of this embodiment is a sintered electrode layer, which is an electrode layer made of a sintered body. The positive electrode layer 622 does not contain a binder. The lithium composite oxide is a sintered electrode layer made of Li ｘ MO ２ (0.05<x<1.10, M is at least one transition metal, and M typically includes one or more of Co (cobalt), Ni (nickel), and Mn (manganese). The average pore size of the sintered body constituting the positive electrode layer 622 is, for example, 0.2 μm or more and 5.0 μm or less.
[0033] The negative electrode layer 623 is laminated on a second main surface 621B of the separator film 621, which is located on the opposite side in the thickness direction to the first main surface 621A. The negative electrode layer 623 includes carbon such as graphite as a negative electrode active material and a binder such as styrene butadiene rubber (SBR) or polyvinylidene fluoride (PVDF). In the present embodiment, only one separator film 621, one positive electrode layer 622, and one negative electrode layer 623 are housed in the exterior film 600 (in the internal space 600C) as an exterior material.
[0034] The positive electrode current collector foil 624 is laminated on the side of the positive electrode layer 622 opposite to the separator film 621. The positive electrode current collector foil 624 is a foil made of a metal that is an electrical conductor. For example, Al (aluminum) can be used as the metal constituting the positive electrode current collector foil 624. The positive electrode current collector foil 624 is disposed between the positive electrode layer 622 and the inner surface 600A of the exterior film 600. The positive electrode current collector foil 624 is disposed along the inner surface 600A of the exterior film 600.
[0035] The negative electrode current collector foil 625 is laminated on the negative electrode layer 623 on the side opposite to the separator film 621. The negative electrode current collector foil 625 is a foil made of a metal that is an electrical conductor. Examples of metals that can be used to form the negative electrode current collector foil 625 include Cu (copper) and Al. The negative electrode current collector foil 625 is disposed between the negative electrode layer 623 and the inner surface 600A of the exterior film 600. The negative electrode current collector foil 625 is disposed along the inner surface 600A of the exterior film 600.
[0036] The electrolyte 626 is impregnated into the separator film 621, the positive electrode layer 622, and the negative electrode layer 623. The electrolyte 626 is a solution of a lithium salt (e.g., LiPF ) in an organic solvent (e.g., a mixed solvent of ethylene carbonate (EC) and methyl ethyl carbonate (MEC), a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC), or a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC)). ６ ) A solution in which a salt is dissolved can be used.
[0037] The positive electrode tab terminal 631 is connected to the battery body 620 between the pair of exterior films 600 and extends to the outside. The negative electrode tab terminal 632 is connected to the battery body 620 between the pair of exterior films 600 and extends to the outside. The positive electrode tab terminal 631 is connected to the positive electrode current collector foil 624. The negative electrode tab terminal 632 is connected to the negative electrode current collector foil 625. The positive electrode tab terminal 631 and the negative electrode tab terminal 632 have a strip-like shape. Referring to FIG. 7 , the positive electrode tab terminal 631 includes a conductive main body 631A and a resin protective layer 631B arranged to cover the surface of the main body 631A. The negative electrode tab terminal 632 includes a conductive main body 632A and a resin protective layer 632B arranged to cover the surface of the main body 632A. The conductors constituting the main bodies 631A and 632A may be metals such as aluminum (Al) and nickel (Ni).
[0038] Next, a sensor-equipped rotating body of this embodiment will be described. FIG. 8 is a schematic diagram showing the structure of the sensor-equipped rotating body. Referring to FIG. 8, the sensor-equipped rotating body 100 includes a rotating body 101 that can rotate around a central axis A in the direction of arrow B, and the sensor module 1 of this embodiment that is installed at a position away from the central axis A of the rotating body 101. The sensor module 1 is installed on the rotating body 101 while being housed in a case 102. In this embodiment, the rotating body 101 includes an outer peripheral surface 101A having a cylindrical surface shape and a pair of end surfaces 101B that close both ends of the outer peripheral surface 101A. In this embodiment, the sensor module 1 is installed on the outer peripheral surface 101A, but it may also be installed on the end surface 101B.
[0039] The shape of rotating body 101 in this embodiment is illustrative and may be other shapes. Rotating body 101 may be, for example, a rotary tool for performing milling or the like, a generator or an airplane turbine, a mixer, a winding machine, a rotary press, a mixer, a winding machine, a rotary press, a paper machine, or the like. Referring to FIGS. 8 and 6 , in sensor-equipped rotating body 100 of this embodiment, positive electrode layer 622, which is a sintered electrode layer, is located closer to central axis A than separator film 621.
[0040] In the lithium-ion secondary battery 60 included in the sensor module 1 of this embodiment, the positive electrode layer 622 is a sintered electrode layer, which is an electrode layer made of a sintered body. Therefore, even when centrifugal force is applied, the positive electrode layer 622 retains the electrolyte 626. In the sensor-equipped rotating body 100, the positive electrode layer 622, which is a sintered electrode layer, is located closer to the central axis A than the separator film 621. Therefore, in the sensor-equipped rotating body 100, even if the electrolyte 626 is biased due to centrifugal force caused by the rotation of the rotating body 101, the positive electrode layer 622, which has a higher electrolyte 626 retention capacity, is located closer to the central axis A than the separator film 621, thereby suppressing deterioration in the characteristics of the secondary battery. In this way, the sensor module 1 and the sensor-equipped rotating body 100 of this embodiment are sensor modules that can be applied to rotating bodies by suppressing deterioration in the characteristics of the secondary battery, and sensor-equipped rotating bodies in which deterioration in the characteristics of the secondary battery is suppressed.
[0041] Furthermore, in the sensor module 1 of this embodiment, the antenna 31 and the lithium ion secondary battery 60 are arranged so as not to overlap when viewed in a direction perpendicular to the first mounting surface 11. While this structure is not essential for the sensor module of the present disclosure, employing this structure prevents the lithium ion secondary battery 60 from interfering with the signal transmitted from the antenna 31. As a result, it becomes possible to stably transmit a signal from the wireless communication module 30.
[0042] Furthermore, in the sensor module 1 of this embodiment, only one separator film 621, one positive electrode layer 622, and one negative electrode layer 623 are housed within the exterior film 600 (in the internal space 600C). While this structure is not essential for the sensor module of the present disclosure, employing this structure reduces the thickness of the lithium-ion secondary battery 60, thereby contributing to a reduction in the thickness of the sensor module 1.
[0043] In addition, it is preferable that the sensor module 1 or the case 102 in the above embodiment be marked with an indication indicating the stacking direction of the separator film 621, the positive electrode layer 622, and the negative electrode layer 623 in the battery body 620, i.e., the orientation in which the sensor module 1 should be positioned to prevent deterioration in the characteristics of the lithium ion secondary battery 60.
[0044] In the sensor module 1, both the positive electrode layer 622 and the negative electrode layer 623 may be sintered electrode layers. ４ Ti ５ O １２ (hereinafter referred to as LTO) or niobium titanium composite oxide Nb ２ TiO ７ A titanium-containing sintered body containing the above-mentioned titanium compound can be used. This configuration makes it possible to suppress deterioration in the characteristics of the lithium-ion secondary battery 60 due to the action of centrifugal force, regardless of the installation mode of the sensor module 1. Furthermore, contrary to the above embodiment, the negative electrode layer 623 does not have to be a sintered electrode layer, and the positive electrode layer 622 does not have to be a sintered electrode layer.
[0045] In the above-described embodiment, a resin film is used as the separator film 621, but the present invention is not limited to this. For example, the separator film 621 may be made of a material such as MgO, Al ２ O ３ , ZrO ２ , SiC, Si ３ N ４ Ceramic films selected from AlN and cordierite can be used.
[0046] It should be understood that the embodiments disclosed herein are illustrative in all respects and are not limiting in any respect. The scope of the present disclosure is defined not by the above description but by the scope of the claims, and it is intended to include all modifications within the meaning and scope of the claims.
[0047] 1 Sensor module, 10 Wiring board, 11 First mounting surface, 12 Second mounting surface, 20 Acceleration sensor, 30 Wireless communication module, 31 Antenna, 40 Wireless charging module, 51 Electronic component, 60 Lithium ion secondary battery, 100 Rotating body with sensor, 101 Rotating body, 101A Outer peripheral surface, 101B End surface, 102 Case, 600 Exterior film, 600A Inner surface, 600B Outer surface, 600C Internal space, 601 First outer edge, 602 Second outer edge, 603 Third outer edge, 604 Fourth outer edge, 620 Battery body, 621 Separator film, 621A First main surface, 621B Second main surface, 622 Positive electrode layer, 623 Negative electrode layer, 624 Positive electrode current collector foil, 625 Negative electrode current collector foil, 626 Electrolyte, 631 Positive electrode tab terminal, 631A main body, 631B protective layer, 632 negative electrode tab terminal, 632A main body, 632B protective layer, A central axis.
Claims
1. A sensor module installed at a position away from the central axis of a rotating body that is rotatable around a central axis, A wiring board including a first mounting surface and a second mounting surface located on the opposite side of the first mounting surface in the thickness direction, A sensor disposed on the first mounting surface, A wireless communication module, which is disposed on the first mounting surface, includes an antenna, and is electrically connected to the sensor, The system comprises a secondary battery disposed on the second mounting surface and supplying power to the sensor and the wireless communication module, The aforementioned secondary battery is The device includes a separator, a positive electrode layer and a negative electrode layer arranged on either side of the separator, an electrolyte impregnated in the separator, the positive electrode layer and the negative electrode layer, and an outer casing material that houses the separator, the positive electrode layer, the negative electrode layer and the electrolyte. A sensor module in which at least one of the positive electrode layer and the negative electrode layer is a sintered electrode layer, which is an electrode layer made of a sintered body.
2. The sensor module according to claim 1, wherein the average pore size of the sintered body constituting the sintered electrode layer is 0.2 μm or more and 5.0 μm or less.
3. The sensor module according to claim 1, wherein both the positive electrode layer and the negative electrode layer are the sintered electrode layer.
4. The sensor module according to claim 1, wherein the antenna and the secondary battery do not overlap when viewed in a direction perpendicular to the first mounting surface.
5. The sensor module according to claim 1, wherein only one of each of the separator, the positive electrode layer, and the negative electrode layer is housed within the outer casing.
6. The sensor module according to claim 1, further comprising a wireless charging module disposed on the first mounting surface and electrically connected to the secondary battery.
7. The sensor module according to claim 1, wherein the sensor is an acceleration sensor or a temperature sensor.
8. A rotating body that can rotate around a central axis, The rotating body is equipped with a sensor module according to any one of claims 1 to 7, which is installed at a position away from the central axis of the rotating body, A rotating body with a sensor, wherein the sintered electrode layer is positioned closer to the central axis than the separator.