Electronic components
The capacitor array with a parallel element group and bypass system addresses capacitor abnormalities by maintaining functionality and safety, minimizing capacitance changes and resonant frequency deviations.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2022-08-05
- Publication Date
- 2026-07-29
AI Technical Summary
If an abnormality occurs in some of the capacitors in a capacitor array, the characteristics of the electronic component change, leading to potential deterioration of device functions.
An electronic component with a parallel element group and a bypass system that short-circuits faulty capacitor elements, maintaining voltage application to functional elements and minimizing characteristic changes.
This approach allows continuous use of the component by preventing significant changes in capacitance and resonant frequency, reducing the need for frequent maintenance and ensuring safety by automatically disconnecting faulty elements.
Smart Images
Figure 0007897077000001 
Figure 0007897077000002 
Figure 0007897077000003
Abstract
Description
Technical Field
[0004] ,
[0006] , , , , , ,
[0005] , , , , , ,
[0001] The present invention relates to electronic components.
Background Art
[0002] Patent Document 1 discloses a conventional non-contact power supply system that uses a capacitor array having a plurality of capacitors in a resonator, which is one of the components constituting a power transmission device or a power reception device.
Prior Art Document
Patent Document
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] If an abnormality occurs in some of the plurality of capacitors constituting an electronic component such as a capacitor array, the characteristics of the electronic component may change, and the functions of a device using the electronic component may deteriorate.
[0005] The present invention has been made paying attention to such problems, and an object thereof is to be able to suppress a change in characteristics of an electronic component to a low level even if an abnormality occurs in some of the plurality of capacitors constituting the electronic component.
Means for Solving the Problems
[0006] In order to solve the above problems, an electronic component according to an aspect of the present invention includes a parallel element group in which a plurality of series element groups each composed of a plurality of capacitor elements connected in series are connected in parallel, and a bypass configured to short-circuit the capacitor element or some of the capacitor elements including the capacitor element when an abnormality occurs in the capacitor element.
Effects of the Invention
[0007] According to this aspect of the present invention, even if some of the capacitor elements in a series group are short-circuited by bypass and disconnected from the conductive path, a voltage can continue to be applied to the remaining capacitor elements in the series group. This makes it possible to avoid using the faulty capacitor element while keeping changes in the characteristics of the electronic component to a minimum. [Brief explanation of the drawing]
[0008] [Figure 1] Figure 1 is a circuit diagram showing a capacitor array according to a first embodiment of the present invention. [Figure 2] Figure 2 is a circuit diagram showing a modified example of the capacitor array according to the first embodiment of the present invention. [Figure 3] Figure 3 is a circuit diagram showing the state when one capacitor element is short-circuited in the capacitor array according to the first embodiment of the present invention. [Figure 4] Figure 4 is a schematic partial plan view of a capacitor array according to the first embodiment of the present invention. [Figure 5A] Figure 5A is a schematic cross-sectional view along the VV line in Figure 4, when the capacitor element is functioning normally. [Figure 5B] Figure 5B is a schematic cross-sectional view along the VV line in Figure 4, showing the case where the capacitor element is overheating abnormally. [Figure 6] Figure 6 is a circuit diagram showing a capacitor array similar to that shown in Figure 1, and is intended to explain how the terminal voltage of the remaining capacitor elements changes when some of the capacitor elements constituting the series element group are short-circuited. [Figure 7] Figure 7 is a circuit diagram showing a capacitor array according to a second embodiment of the present invention. [Figure 8] Figure 8 is a schematic perspective view of a heating unit according to a modification of the third embodiment of the present invention. [Figure 9] Figure 9 is a circuit diagram showing the state when one capacitor element is short-circuited in a capacitor array according to a comparative example different from the present invention. [Modes for carrying out the invention]
[0009] The embodiments will be described in detail below with reference to the drawings. In the following description, similar components will be given the same reference numeral.
[0010] (First Embodiment) Figure 1 is a circuit diagram showing a capacitor array 100 according to the first embodiment of the present invention.
[0011] As shown in Figure 1, the capacitor array 100 comprises a plurality of capacitor elements 1 and bypasses 2 for isolating each capacitor element 1 from the conductive path. The capacitor array 100 can be used, for example, as a component for forming a resonator in a power transmission or power receiving device of a contactless power supply system. Details of each component of the capacitor array 100 will be described below.
[0012] Each capacitor element 1 in the capacitor array 100 is connected such that the change from the initial value of the combined capacitance of the capacitor array 100 is small, so that even if some capacitor elements 1 are disconnected from the conductive path, the components configured using the capacitor array 100 can continue to be used. Specifically, each capacitor element 1 is connected such that they form at least one parallel element group 3.
[0013] The parallel element group 3 is a group of capacitor elements formed by connecting two or more series element groups 4, each consisting of two or more capacitor elements 1 connected in series, in parallel. Figure 1 shows an example of the parallel element group 3, where three series element groups 4, each consisting of four capacitor elements 1 connected in series, are connected in parallel. However, the configuration of the parallel element group 3 is not limited to this configuration.
[0014] Fig. 1 shows a capacitor array 100 composed of one parallel element group 3. However, the configuration of the capacitor array 100 is not limited to such a configuration. For example, like the capacitor array 100 according to the modification shown in Fig. 2, it may be configured such that a plurality of parallel element groups 3 are connected in series-parallel, or (not shown) it may be configured such that a plurality of parallel element groups 3 are connected in series or in parallel.
[0015] As in this embodiment, by connecting the series element groups 4 in parallel, the combined capacitance of the capacitor array 100 can be increased accordingly. And until all the capacitor elements 1 of any one of the series element groups 4 are disconnected from the conductive path, as shown in Fig. 3, even if some of the capacitor elements 1 in one of the series element groups 4 are short-circuited by the bypass 2 and disconnected from the conductive path, a voltage can be applied to each capacitor element 1 that has not been disconnected from the conductive path of each series element group 4. Therefore, the change in the combined capacitance of the parallel element group 3, and thus the capacitor array 100, can be minimized.
[0016] On the other hand, for example, like the capacitor array 100 according to the comparative example shown in Fig. 9, when one capacitor element 1 is connected in parallel without forming a series element group, if one of the capacitor elements 1 connected in parallel (capacitor element 1A in Fig. 9) is disconnected from the conductive path, a voltage cannot be applied to all the other capacitor elements 1B, 1C, 1D connected in parallel with the capacitor element 1A. Therefore, even if one capacitor element 1 is disconnected from the conductive path, the combined capacitance of the capacitor array 100 changes significantly. For example, when the capacitor array 100 according to the comparative example is used as a resonator, which is one of the components constituting the power transmission device or the power reception device of a non-contact power supply system, the resonance frequency may deviate from the desired frequency, and there is a risk that the power transmission and reception efficiency deteriorates.
[0017] Returning to FIG. 1, the bypass 2 is configured to be able to disconnect the capacitor element 1 from the conductive path when an abnormality occurs in the capacitor element 1 due to, for example, a failure or aging deterioration. In particular, the bypass 2 according to the present embodiment is configured to be able to automatically disconnect the capacitor element 1 from the conductive path when the capacitor element 1 abnormally generates heat due to a failure or aging deterioration or the like. Hereinafter, the detailed configuration of the bypass 2 according to the present embodiment will be described with reference to FIGS. 4, 5A, and 5B.
[0018] FIG. 4 is a schematic partial plan view of the capacitor array 100, showing one of the plurality of capacitor elements 1 arranged on the substrate 101. FIG. 5A is a schematic cross-sectional view taken along the line V-V of FIG. 4 when the capacitor element 1 is normal. On the other hand, FIG. 5B is a schematic cross-sectional view taken along the line V-V of FIG. 4 when the capacitor element 1 is abnormally generating heat.
[0019] As shown in FIGS. 4 and 5A, the capacitor element 1 is attached to the surface side of the first layer 101A of the multi-layer substrate 101. One terminal of the capacitor element 1 is electrically connected to the substrate terminal 102A via the metal foil 103A, and the other terminal is similarly electrically connected to the substrate terminal 102B via the metal foil 103B.
[0020] A space is formed between the first layer 101A of the substrate 101 and the second layer 101B disposed on the back side of the first layer 101A. On the back side of the attachment portion of the capacitor element 1, a closed space 105 is formed by the substrate 101 and the two bypass terminals 104A and 104B.
[0021] The bypass terminal 104A is electrically connected to the substrate terminal 102A via the metal foil 103A and is attached to the substrate 101 so that a part thereof functions as a wall surface constituting the closed space 105. The bypass terminal 104B is electrically connected to the substrate terminal 102B via the metal foil 103B and is attached to the substrate 101 so that a part thereof functions as a wall surface constituting the closed space 105, similar to the bypass terminal 104A.
[0022] A conductive low-melting-point metal 106 is placed in the closed space 105. As shown in Figure 5A, the low-melting-point metal 106 is placed in the closed space 105 such that the bypass terminals 104A and 104B do not conduct electricity when the capacitor element 1 is functioning normally.
[0023] On the other hand, as shown in Figure 5B, when an abnormality occurs in the capacitor element 1 and the temperature of the capacitor element 1 (hereinafter referred to as "element temperature") becomes higher than normal, that is, when the element temperature exceeds a predetermined temperature higher than the normal temperature, the low-melting-point metal 1 melts upon receiving heat from the capacitor element 1, causing the bypass terminals 104A and 104B to conduct electricity. This makes it possible to form a conductive path (substrate terminal 102A → metal foil 103A → bypass terminal 104A → low-melting-point metal 106 → bypass terminal 104B → metal foil 103B → substrate terminal 102B) that short-circuits the capacitor element 1 when an abnormality occurs in the capacitor element 1. Furthermore, if the substrate 101 is tilted, even if the capacitor element 1 overheats abnormally, the low-melting-point metal 106 may not melt and flow to a conductive position as shown in Figure 5B, and may be biased towards one of the bypass terminals 104A or 104B, preventing conductivity. In such cases, it is possible to minimize the size of the closed space 105 and to increase the wettability of the substrate 101 to the low-melting-point metal 106.
[0024] In this embodiment, the bypass terminals 104A and 104B were connected by melting a low-melting-point metal 106 placed in the closed space 105 with the heat of the capacitor element 1. However, the invention is not limited to this, and for example, the bypass terminals 104A and 104B can also be connected by expanding a conductive member placed in the closed space 105 with the heat of the capacitor element 1. Alternatively, for example, a conductive spring compressed by a low-melting-point insulating member (such as glass) can be placed in the closed space 105, and the conductive spring can be extended by melting the insulating member with the heat of the capacitor element 1, thereby connecting the bypass terminals 104A and 104B.
[0025] The capacitor array 100 (electronic component) according to this embodiment described above comprises a parallel element group 3 formed by connecting multiple series element groups 4, each consisting of multiple capacitor elements 1 connected in series, in parallel, and a bypass 2 configured to short-circuit a capacitor element 1 when an abnormality occurs in the capacitor element 1.
[0026] As a result, even if some of the capacitor elements 1 in the series element group 4 are short-circuited by the bypass 2 and disconnected from the conductive path, a voltage can still be applied to the remaining capacitor elements 1 in the series element group 4. This makes it possible to avoid using the faulty capacitor element 1 while suppressing changes from the initial value of the combined capacitance of the capacitor array 100.
[0027] Therefore, for example, if the capacitor array 100 is used in a resonator, which is one of the components of a power transmission or power receiving device in a contactless power supply system, even if some capacitor elements 1 malfunction, it is possible to suppress the resonant frequency from deviating significantly from the desired frequency, thereby suppressing the deterioration of power transmission and reception efficiency. As a result, even if some capacitor elements 1 malfunction, the components configured using the capacitor array 100 can be used continuously. In particular, if the capacitor array 100 is used in a power transmission device, the power transmission device needs to be installed underground, making replacement and inspection work difficult. However, if it can be used continuously even if some capacitor elements 1 malfunction, the need for frequent replacement and inspection work is eliminated, thus reducing the man-hours required for replacement and inspection work.
[0028] Furthermore, the bypass 2 according to this embodiment is configured to automatically short-circuit the capacitor element 1 when its temperature exceeds a predetermined temperature. Specifically, the bypass 2 includes a conductive member that is positioned between the terminals of the capacitor element 1 and deforms to short-circuit the terminals of the capacitor element 1 when its temperature exceeds a predetermined temperature. The conductive member is a low-melting-point metal 106 that melts when the temperature of the capacitor element 1 exceeds a predetermined temperature.
[0029] This ensures the safety of the component by automatically disconnecting the capacitor element 1 from the conductive path if it overheats. Furthermore, since the low-melting-point metal 106 is used to melt (deform) the capacitor element 1 and short-circuit both terminals, even after the temperature of the capacitor element 1 decreases due to being disconnected from the conductive path, the two terminals of the capacitor element 1 remain short-circuited by the low-melting-point metal 106 that has solidified after melting. Therefore, it is possible to prevent voltage from being applied again to the capacitor element 1 once a malfunction has occurred.
[0030] (Second Embodiment) Next, a second embodiment of the present invention will be described. This embodiment differs from the first embodiment in that it allows for the determination of the degree of abnormality in the capacitor array 100. The following will focus on explaining these differences.
[0031] In the first embodiment, the capacitor element 1 could be disconnected from the conductive path if it overheated abnormally. However, as the number of capacitor elements 1 disconnected from the conductive path increases, the change in the total capacitance of the capacitor array 100 from its initial value also increases. Therefore, if the number of capacitor elements 1 that constitute the capacitor array 100 and have been disconnected from the conductive path exceeds a certain number, it is desirable to stop using the component including the capacitor array 100, or to replace the capacitor array 100 or the component including the capacitor array 100 with a new component.
[0032] Here, Figure 6 shows a capacitor array 100 similar to the one shown in Figure 1. In Figure 6, if the capacitance of each capacitor element 1 is the same, and the voltage applied across the series element group 4A is V, then the terminal voltages of each capacitor element 1A to 1D constituting the series element group 4A will be 1 / 4V when all capacitor elements 1A to 1D are functioning normally. If one of them is abnormal (for example, if one of them is short-circuited by bypass 2), the terminal voltages of the remaining three elements will be 1 / 3V. If two of them are abnormal, the terminal voltages of the remaining two elements will be 1 / 2V. If all three are abnormal, the terminal voltage of the remaining element will be V.
[0033] In other words, in the series element group 4, the more capacitor elements (hereinafter referred to as "abnormal elements") that are disconnected from the conductive path increase, the higher the terminal voltage of the normal capacitor elements 1 that are not disconnected from the conductive path becomes.
[0034] Therefore, in this embodiment, as shown in Figure 7, at least one reference capacitor element (hereinafter referred to as "reference element") is provided in each series element group 4, and the terminal voltage of each reference element is detected by a voltage sensor 5. Based on the terminal voltage of each reference element, the number of abnormal elements, i.e., the degree of abnormality of the capacitor array 100, is determined. In Figure 7, one reference terminal is set in each series element group 4 and the terminal voltage of that reference terminal is detected, but this is not limited to this, and two or more capacitor elements 1 connected in series may be used as reference terminals and the terminal voltages between those multiple capacitor elements may be detected.
[0035] Each series element group 4 consists of a reference element and capacitor elements other than the reference element (hereinafter referred to as "non-reference elements"). When the reference element is functioning normally, the voltage across the terminals of the reference element increases as the number of non-reference elements disconnected from the conductive path increases. Therefore, by monitoring the voltage across the terminals of the reference element, it is possible to determine the number of non-reference elements disconnected from the conductive path within the series element group 4 including the reference element, i.e., the number of abnormal elements (the degree of abnormality of the capacitor array 100).
[0036] Specifically, by comparing the terminal voltage of the reference element 1 with one or more thresholds, the number of non-reference elements 1 that have been disconnected from the conductive path within the series element group including the reference element 1 can be determined. The threshold can be a fixed value set in advance if the voltage applied to the capacitor array 100 is constant, while it is preferable to use a variable value corresponding to the applied voltage if the voltage applied to the capacitor array 100 fluctuates.
[0037] If the reference element becomes an abnormal element (i.e., if the terminal voltage of the reference element falls below 0[V] or a threshold that can be considered as 0[V]), it becomes impossible to determine the number of abnormal elements in the series element group 4 that includes the reference element. In this case, to be on the safe side, it may be determined that all capacitor elements 1 in the series element group 4 that includes the reference element are abnormal elements. This is because if the reference element is selected from among many capacitor elements 1 and found to be abnormal, it can be determined that there is a high probability that the other capacitor elements 1 are also abnormal.
[0038] The capacitor array 100 (electronic component) according to this embodiment described above further includes a voltage sensor 5 that detects the voltage between one or more capacitor elements in the series element group 4, and is configured to determine the number of capacitor elements 1 that have been short-circuited by the bypass 2, or to determine the degree of abnormality of the capacitor array 100, based on the voltage value detected by the voltage sensor 5.
[0039] Specifically, by comparing the voltage value detected by the voltage sensor 5 with a predetermined threshold, the number of capacitor elements 1 that have been short-circuited by the bypass 2 is determined, or the degree of abnormality of the capacitor array 100 is determined. The predetermined threshold is either a fixed value set in advance according to the voltage applied to the series element group 4, or a variable value that changes according to the voltage applied to the series element group 4.
[0040] This allows us to prompt users of equipment containing a capacitor array 100 where the number of capacitor elements 1 disconnected from the conductive path exceeds a certain number to stop using the equipment or replace the components.
[0041] As mentioned above with reference to Figure 6, in the series element group 4, the voltage applied to the normal capacitor elements 1 that are not disconnected from the conductive path increases as the number of capacitor elements 1 disconnected from the conductive path increases. Therefore, when the number of capacitor elements 1 disconnected from the conductive path exceeds a certain number, the voltage applied to the normal capacitor elements 1 may exceed the withstand voltage.
[0042] Therefore, even if the total number of faulty elements in the capacitor array is below a certain number, if the terminal voltage of the reference element exceeds the upper limit voltage set based on the withstand voltage, it may be possible to prompt the user to stop using the system or replace the component, regardless of the number of faulty elements.
[0043] (Third embodiment) Next, a third embodiment of the present invention will be described. This embodiment differs from the above embodiments in that the capacitor element 1 can be actively disconnected from the conductive path. The following will focus on explaining this difference.
[0044] In the embodiments described above, the capacitor element 1 could not be disconnected from the conductive path unless it overheated abnormally.
[0045] In contrast, although abnormal heat generation does not occur, the capacitance of each capacitor element 1 may decrease due to deterioration over time. When this happens, the combined capacitance of the capacitor array 100 also changes, and if the capacitor array 100 is used as a resonator, which is one of the components of the power transmission or power receiving device of a contactless power supply system, the resonant frequency may deviate from the desired frequency, potentially worsening the power transmission and reception efficiency.
[0046] Therefore, in this embodiment, as shown in Figure 8, a bypass 6 (hereinafter referred to as "second bypass 6") separate from the bypass 2 described in the first embodiment is provided for some of the capacitor elements 1. The second bypass 6 is a switch that can actively disconnect the capacitor elements 1 from the conductive path, and can be, for example, a semiconductor switch using a MOSFET or a mechanical switch such as a relay.
[0047] The combined capacitance of the capacitor array 100 decreases as the number of capacitor elements 1 in each series element group 4 increases. Therefore, as shown in Figure 8, by providing a second bypass 6 for some of the capacitor elements 1 in each series element group 4, when a decrease in the combined capacitance of the capacitor array 100 is observed, the combined capacitance of the capacitor array 100 can be increased by actively disconnecting some of the capacitor elements 1 in each series element group 4 from the conductive path using the second bypass 6.
[0048] In this embodiment, the second bypass 6 is initially open. However, if one capacitor element 1 in the series element group 4 experiences a heat failure and shorts the bypass terminal 104, increasing the combined capacitance, and it is desired to reduce the combined capacitance to approach the original combined capacitance, the second bypass 6 may be initially short-circuited and then opened when the faulty capacitor element 1 is short-circuited. Furthermore, in this embodiment, Figure 8 shows an example where some capacitor elements 1 are equipped with both bypass 2 and second bypass 6. However, some capacitor elements 1 may be configured to be equipped only with the second bypass 6.
[0049] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. For example, in the above embodiment, the bypass 2 was configured to short-circuit one capacitor element 1, but the bypass 2 may also be configured to short-circuit multiple capacitor elements 1 connected in series. [Explanation of Symbols]
[0050] 1 Capacitor element 2 Bypass 3 Parallel element group 4 series element group 6. Second Bypass 100 Capacitor Array (Electronic Component) 106 Low-melting-point metals (conductive materials)
Claims
1. A group of parallel elements formed by connecting multiple series element groups, each consisting of multiple capacitor elements arranged on a substrate and connected in series, in parallel, A bypass is configured to automatically and irreversibly short-circuit the terminals of the capacitor element by a conductive member that deforms or melts in response to the heat of the capacitor element when the temperature of the capacitor element exceeds a predetermined temperature, Equipped with, The conductive member is placed in a closed space formed by the substrate and the bypass terminal attached to the substrate. Electronic components.
2. The conductive member is a low-melting-point metal that melts when the temperature of the capacitor element reaches or exceeds the predetermined temperature. The electronic component according to claim 1.
3. The system further includes a voltage sensor that detects the voltage between one or more capacitor elements in the series group, Based on the voltage value detected by the voltage sensor, the system is configured to determine the number of capacitor elements short-circuited by the bypass, or to determine the degree of abnormality of the electronic component. The electronic component according to claim 1 or 2.
4. By comparing the voltage value detected by the voltage sensor with a predetermined threshold, the number of capacitor elements short-circuited by the bypass can be determined, or the degree of abnormality of the electronic component can be determined. The predetermined threshold is a fixed value set in advance according to the voltage applied to the series element group, or a variable value that changes according to the voltage applied to the series element group. The electronic component according to claim 3.
5. The system further comprises a second bypass that actively short-circuits one or more of the capacitor elements. The electronic component according to claim 1.