Temperature increasing system

Abstract

Provided is a heating system that suppresses heat generation caused by current flowing in normal charge and discharge of a secondary battery, and at the same time generates heat by flowing high-frequency alternating current, thereby heating the secondary battery when necessary, and enables improvement in energy efficiency. The heating system includes: an alternating current generation circuit connected to a storage battery including one or more storage bodies, and generating alternating current; and a conductive member that is a metal conductor connected between a terminal portion of the storage body and the alternating current generation circuit, or between the plurality of storage bodies, and has a first path and a second path that generates heat by passing the alternating current, the first path having a larger inductance component than the second path.

Description

Technical Field

[0001] This invention relates to a heating system. Background Technology

[0002] Efforts to mitigate the adverse environmental impacts of the Earth (such as reducing NOx, SOx, or CO2) are progressing steadily. Therefore, in recent years, from the perspective of improving the Earth's environment and reducing CO2, there has been increasing attention on electric vehicles that operate at least through an electric motor, such as hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs), which are powered by electricity supplied by a battery (secondary battery). Furthermore, the use of lithium-ion secondary batteries for vehicle applications has been studied. In these electric vehicles, maximizing the performance of the secondary battery is crucial. It is known that the charge and discharge performance of a secondary battery decreases when the temperature drops below a suitable range during use. However, by raising the secondary battery to a suitable temperature during use, the decline in charge and discharge performance can be suppressed.

[0003] However, for example, Japanese Patent Nos. 4940490 and 5096842 disclose techniques for cooling the battery interior by cooling the battery terminals. Furthermore, Japanese Patent No. 4940490 describes a technique that widens the contact area between the terminals and the heat dissipation member by bringing the heat dissipation member into contact with the end face of the battery terminals, thereby improving the efficiency of heat transfer from the terminals to the heat dissipation member. The aforementioned prior art utilizes the good heat transfer between the battery terminals and the battery interior to efficiently dissipate heat from the battery. Therefore, conversely, when heating a secondary battery, heating the terminals can achieve efficient temperature increases.

[0004] On the other hand, for example, Japanese Patent No. 5293820 discloses a technology related to a heating device for heating a secondary battery. In the heating device disclosed in Japanese Patent No. 5293820, based on the frequency characteristics of the impedance of the secondary battery, a pulsating current of a predetermined frequency in a frequency region where the absolute value of the impedance relatively decreases is actively generated in the secondary battery, thereby heating the secondary battery. Summary of the Invention

[0005] However, when considering the use of existing technologies to heat a secondary battery, one possibility is that a high-frequency alternating current flows through a metal component (a heat dissipation component in Japanese Patent No. 4940490 and Japanese Patent No. 5096842) that is in contact with the terminals of the secondary battery, causing the metal component to heat up. In this case, to further generate heat by the alternating current flowing through the metal component, it is necessary to increase the resistance of the metal component. However, increasing the resistance of the metal component may affect the normal charge and discharge characteristics of the secondary battery. For example, if the metal component heats up due to the current flowing during normal charge and discharge, the secondary battery will heat up even when heating is not required.

[0006] This invention is based on the understanding of the above-mentioned problems. One of its objectives is to provide a heating system that suppresses the heat generated by the current flowing during the normal charging and discharging of a secondary battery, while simultaneously generating heat by flowing a high-frequency alternating current, thereby heating the secondary battery when necessary and improving energy efficiency.

[0007] [Solution to the problem]

[0008] The heating system of the present invention adopts the following structure.

[0009] (1): A heating system according to one aspect of the present invention comprises: an AC generating circuit connected to a battery containing one or more energy storage elements and generating an AC current; and a conductive member, which is a conductive member of a metal conductor connected between the terminal portion of the energy storage element and the AC generating circuit, or between the multiple energy storage elements, and having a first path and a second path for heating by allowing the AC current to pass through, wherein the first path has a larger inductance component than the second path.

[0010] (2): In the above (1) scheme, the conductive component is provided with a first resistive component and an inductive component in the first path, and a second resistive component is provided in the second path, wherein the resistance value of the second resistive component is higher than the resistance value of the first resistive component.

[0011] (3): In the above (2) scheme, a reactor having the first resistive component and the inductive component is provided in the first path, and a resistor having the second resistive component is provided in the second path.

[0012] (4): In the above (2) scheme, a metal conductor having the first resistive component and a magnetic body surrounding the metal conductor are provided in the first path, and a resistor having the second resistive component is provided in the second path.

[0013] (5): A heating system according to one aspect of the present invention includes: an AC generating circuit connected to a battery containing one or more energy storage elements and generating an AC current; and a conductive member, which is a conductive member of a metal conductor connected between the terminal portion of the energy storage element and the AC generating circuit, or between the multiple energy storage elements, and is provided with a magnetic body surrounding the metal conductor that is heated by an AC magnetic field generated based on the AC current.

[0014] (6): A heating system according to one aspect of the present invention comprises: an AC generating circuit connected to a battery containing one or more energy storage elements and generating an AC current; and a conductive member, which is a conductive member of a metal conductor connected between the terminal portion of the energy storage element and the AC generating circuit, or between the multiple energy storage elements, and having a first path and a second path branching from the first path and passing through which the AC current passes and generates heat, wherein a resistor is provided in the second path.

[0015] (7): In any of the above (1) to (6), the AC generating circuit has a first capacitor connected at one end to the positive side of the energy storage body and a second capacitor connected at one end to the negative side of the energy storage body. By switching the connection of the first capacitor and the second capacitor to the energy storage body to a series connection or a parallel connection, the AC current is generated by the resonant action of the inductive component of the energy storage body and at least the first capacitor.

[0016] [Invention Effects]

[0017] According to the schemes (1) to (7) above, the heat generated by the current flowing during the normal charging and discharging of the secondary battery is suppressed, and at the same time, the heat generated by the flow of high-frequency alternating current is achieved, thereby raising the temperature of the secondary battery when necessary, and thus improving the energy efficiency. Attached Figure Description

[0018] Figure 1 This is a diagram illustrating an example of the structure of the heating system in the embodiment.

[0019] Figure 2 This is a diagram illustrating an example of the structure of an AC generating circuit in a heating system.

[0020] Figure 3 This is a diagram showing an example of the structure of the busbar in the first embodiment.

[0021] Figure 4 This is an example of the equivalent circuit of the bus in the first embodiment.

[0022] Figure 5 This is a diagram illustrating an example of the heating characteristics in the busbar of the first embodiment.

[0023] Figure 6 This is a diagram showing another example of the structure of the busbar in the first embodiment.

[0024] Figure 7 This is a diagram illustrating an example of the structure of the busbar in the second embodiment.

[0025] Figure 8 This is a diagram illustrating an example of the structure of the busbar in the third embodiment.

[0026] Figure 9 This is a diagram showing an applicable example of the busbar in the third embodiment. Detailed Implementation

[0027] Hereinafter, embodiments of the heating system of the present invention will be described with reference to the accompanying drawings.

[0028] [Structure of the heating system]

[0029] Figure 1 This diagram illustrates an example of the structure of a heating system according to an embodiment. The heating system 1, for example, includes an AC generation unit 10 and a bus 20, the AC generation unit 10 including an AC generation circuit 12. Figure 1 The battery 30, which raises the temperature in the heating system 1, is also shown in the diagram. Figure 1 The diagram shows the state in which busbars 20 (busbar 20a and busbar 20b) are connected to the terminals on the positive and negative sides of the battery 30.

[0030] The storage battery 30 is a secondary battery used for driving a hybrid electric vehicle (HEV) (hereinafter referred to as "vehicle M"), which is driven by either an electric motor (electric motor) powered by supplied electricity or an internal combustion engine powered by fuel, such as a diesel engine or a gasoline engine. The storage battery 30 includes, for example, a secondary battery, such as a lithium-ion battery, capable of repeated charging and discharging, as an energy storage section Ba. The storage battery 30 discharges the electricity stored in the energy storage section Ba and supplies it to the electric motor connected to terminals V0 and V1. For example, the electric motor operates as a regenerative brake utilizing the kinetic energy of the vehicle M during deceleration to generate electricity and charges the electricity supplied from terminals V0 and V1. The storage battery 30 is an example of an "energy storage element" or "battery" in the technical solution.

[0031] The heating system 1 raises the temperature of the battery 30 to a suitable operating temperature in order to suppress the decline in the charging and discharging performance of the battery 30. The starting and stopping of the heating system 1 is controlled, for example, by a control device such as an ECU (Electronic Control Unit) provided in the vehicle M.

[0032] The AC generating unit 10 generates a high-frequency alternating current through the AC generating circuit 12 to heat the busbar 20. The busbar 20 is a conductive member, for example, formed primarily of a metal conductor such as copper. The busbar 20 is connected to the terminal portion of the battery 30. During the normal charging and discharging of the battery 30, the busbar 20 allows current (charge / discharge current) to flow between the battery 30 and the terminals V0 and V1. The charge / discharge current is direct current or an alternating current with a lower frequency than the alternating current generated by the AC generating unit 10. When the alternating current generated by the AC generating unit 10 is applied to the battery 30, it heats up in response to that alternating current. The heat emitted by the busbar 20 is transferred to the terminal portion of the battery 30, and further to the interior of the battery 30, causing the battery 30 to heat up. This is because the terminal portion of the battery 30 is connected to the interior of the battery 30 by a metal material, resulting in good heat transfer to the entire battery 30. The busbar 20 is an example of a "conductive member" in the technical solution.

[0033] [Example of the structure of the AC generation unit]

[0034] Figure 2 This diagram illustrates an example of the structure of the AC generating unit 10 included in the heating system 1. The AC generating unit 10 includes, for example, an AC generating circuit 12 and a control unit 14. Figure 2 The heating system 1 also includes a busbar 20 (busbar 20a and busbar 20b) and a battery 30. The battery 30 has a resistor Ra and an inductor La connected in series on the positive terminal side of the energy storage section Ba. The inductor La is an example of the "inductive component of the energy storage element" in the technical solution.

[0035] The AC generating circuit 12 includes, for example, capacitor C1, capacitor C2, switch S1, switch S2, and switch S3. Capacitor C1 and capacitor C2 are capacitors with equal electrostatic capacitance. Switches S1, S2, and S3 are controlled by a control signal output from the control unit 14 to either a conducting state (connecting the terminals, becoming a closed state) or a non-conducting state (disconnecting the terminals, becoming a closed state). Switches S1, S2, and S3 can be semiconductor switching elements, such as N-channel metal oxide semiconductor field-effect transistors (MOSFETs), controlled to either be on or off.

[0036] In the AC generating circuit 12, the first terminal of capacitor C1 is connected to the positive terminal of battery 30, and the first terminal of capacitor C2 is connected to the negative terminal of battery 30. Furthermore, in the AC generating circuit 12, the first terminal of switch S2 is connected to the first terminal of capacitor C1, and the second terminal of switch S1 is connected to the first terminal of capacitor C2. Also in the AC generating circuit 12, the first terminal of switch S1 and the second terminal of switch S3 are connected to the second terminal of capacitor C1, and the second terminal of switch S2 and the first terminal of switch S3 are connected to the second terminal of capacitor C2. In the AC generating circuit 12, capacitor C1 is an example of a "first capacitor" in the technical solution, and capacitor C2 is an example of a "second capacitor" in the technical solution.

[0037] When the heating system 1 is started, the control unit 14 switches the connection of capacitors C1 and C2 to the battery 30 side to either a parallel connection or a series connection by turning on or off the switches provided in the AC generating circuit 12. More specifically, the control unit 14 alternately switches between a state in which capacitors C1 and C2 are connected in parallel to the battery 30 side by turning on switches S1 and S2 and turning off switch S3, and a state in which capacitors C1 and C2 are connected in series to the battery 30 side by turning off switches S1 and S2 and turning on switch S3.

[0038] The control unit 14 performs operations by executing programs (software) through hardware processors such as CPUs (Central Processing Units). The control unit 14 can also be implemented using hardware (including circuitry) such as LSIs (Large Scale Integration), ASICs (Application Specific Integrated Circuits), FPGAs (Field-Programmable Gate Arrays), and GPUs (Graphics Processing Units), or through a combination of software and hardware. The control unit 14 can also be implemented using a dedicated LSI. The program can be pre-stored in a storage device such as a flash memory (a storage device with a non-transitory storage medium) provided in the AC generation unit 10.

[0039] The AC generating circuit 12 switches the connection of capacitors C1 and C2 to the battery 30 side to either a parallel connection or a series connection via the control unit 14, thereby generating an AC current through the resonant operation of the inductor La of the battery 30 and at least capacitor C1. More specifically, the AC generating circuit 12 generates a high-frequency AC current based on the power stored in the battery 30 by resonantly exchanging the magnetic energy stored in the inductor La of the battery 30 and the electrostatic energy stored in at least capacitor C1.

[0040] The AC generating unit 10 heats up the bus 20 by applying (flowing) the AC current generated by the AC generating circuit 12 to the bus 20, thereby raising the temperature of the battery 30.

[0041] <First Implementation Method>

[0042] [Example of busbar structure]

[0043] Figure 3 This diagram illustrates an example of the structure of the busbar 20 (hereinafter referred to as "busbar 20-1") according to the first embodiment. The busbar 20-1 is mainly formed of a metal conductor 21, and two terminal holes (terminal hole A and terminal hole B) are formed at both ends of the metal conductor 21, connecting to the terminal portion of the battery 30, the terminal for outputting alternating current from the alternating current generating unit 10, and the terminal for supplying power to the vehicle M. The busbar 20-1 has two current paths, P1 and P2, between terminal hole A and terminal hole B. In the busbar 20-1, a reactor 22 is provided in current path P1, and a resistor 23 is provided in current path P2.

[0044] Reactor 22 is a reactor for high current applications, having both resistive and inductive components. The resistance of the resistive component in reactor 22 is negligible. Resistor 23 is a resistor whose resistive component has a higher resistance than that of reactor 22. While resistor 23 also contains an inductive component, this inductive component is negligible.

[0045] With this structure, during normal charging and discharging operations of the battery 30 in busbar 20-1, the charging and discharging current of the battery 30 flows through current path P1. On the other hand, when the battery 30 is heated through busbar 20-1, the alternating current generated by the alternating current generating unit 10 flows through current path P2.

[0046] In busbar 20-1, current path P1 is an example of the "first path" in the technical solution, and current path P2 is an example of the "second path" in the technical solution.

[0047] Figure 4 This is an example of the equivalent circuit of bus 20-1 in the first embodiment. Figure 4 In this context, the resistive component of reactor 22 is designated as "Rs", and the inductive component as "Ls". Figure 4 In this circuit, the resistive component of resistor 23 is designated as "Rm". When a charging / discharging current flows between terminal hole A and terminal hole B, in bus 20-1, the charging / discharging current flows through the current path P1 with a lower resistance value, exhibiting characteristics corresponding to the resistive component Rs and the inductive component Ls of reactor 22, respectively. On the other hand, when an alternating current flows between terminal hole A and terminal hole B, in bus 20-1, the inductive component Ls of reactor 22 suppresses the flow of high-frequency alternating current to current path P1, and the alternating current flows through the current path P2 with a higher resistance value, exhibiting characteristics corresponding to the resistive component Rm of resistor 23. As a result, in bus 20-1, resistor 23 heats up in response to the flowing alternating current.

[0048] In busbar 20-1, the resistive component Rs is an example of the "first resistive component" in the technical solution, and the inductive component Ls is an example of the "inductive component" in the technical solution. In busbar 20-1, the resistive component Rm is an example of the "second resistive component" in the technical solution.

[0049] Here, we explain the relationship between the frequency of the current flowing in busbar 20-1 and the heat generated. Figure 5 This is a diagram illustrating an example of the heating characteristics in busbar 20-1 of the first embodiment. Figure 5 (a) shows the power supply PS to Figure 4The equivalent circuit of bus 20-1 shown is an example of a circuit in which currents of the same value but different frequencies are applied. Figure 5 (b) shows that Figure 5 The circuit example shown in (a) illustrates the variation of current flowing in each current path and heat generation relative to frequency. More specifically, Figure 5 (b) shows the variation of the current I1 flowing in current path P1, the current I2 flowing in current path P2, the heat generated in current path P1 W1, the heat generated in current path P2 W2, and the overall heat generated of bus 20-1 with respect to frequency. Figure 5 (a) shows an example of the direction of flow of currents I1 and I2. Figure 5 One example shown is when the power supply PS applies a sinusoidal current I with an amplitude of 20 [A] to the busbar 20-1, which has an inductance component Ls of 100 [nH], a resistance component Rs of 1 [mΩ], and a resistance component Rm of 1 [Ω], of the reactor 22.

[0050] like Figure 5 As shown in the lower part of (b), when the power supply PS applies a current I with a frequency of, for example, less than 50 kHz to the bus 20-1, a current I1 corresponding to the applied current I flows in the current path P1, but a current I2 hardly flows in the current path P2 due to the resistive element 23. Therefore, as Figure 5 As shown in the middle section of (b), when a current I with a frequency below 50 kHz is applied, it can be said that the heat generated W1 in the current path P1 through which the current I1 flows is dominant, while the heat generated W2 in the current path P2 is almost negligible. Therefore, as Figure 5 As shown in the upper part of (b), the overall heat generation of bus 20-1 becomes the heat generation corresponding to heat generation W1. In other words, when a current I with a frequency of less than 50 kHz is applied, bus 20-1 hardly generates heat.

[0051] In contrast, such as Figure 5 As shown in the lower part of (b), when the power supply PS applies a current I with a frequency exceeding 50 kHz to bus 20-1, the current I2 flowing in current path P2 gradually increases with increasing frequency. Conversely, in current path P1, if the frequency of current I further increases, the current I1 gradually decreases. Therefore, as... Figure 5As shown in the middle section of (b), the main heat-generating current path changes when the frequency exceeds 50 kHz. More specifically, in current path P1, the inductive component Ls of reactor 22 suppresses the flow of current I at frequencies exceeding 50 kHz, thus the heat generation W1 in current path P1 remains unchanged. However, the heat generation W2 in current path P2, which has a high-resistivity resistor 23, increases with increasing frequency, becoming the main source of heat generation in bus 20-1 when the frequency exceeds 50 kHz. Therefore, as Figure 5 As shown in the upper part of (b), the overall heat generation of bus 20-1 gradually increases around a frequency of approximately 50 kHz.

[0052] Thus, bus 20-1 has the following heating characteristics: when the frequency of the applied current I is below 50 kHz, the heat generated in the current path P1 is mainly W1, and when the frequency exceeds 50 kHz, the heat generated in the current path P2 is mainly W2.

[0053] Typically, in vehicle M, the frequency of the current associated with the charging and discharging of battery 30 is DC to around a few Hz. Furthermore, the upper limit of the frequency of the current fluctuations (so-called current waveform pulsations) associated with the rotation of the electric motor used for driving is around a few kHz. In addition, the upper limit of the frequency of current waveform pulsations caused by switching of devices such as inverters installed in vehicle M is around tens of kHz.

[0054] Therefore, it can be seen that in the heating system 1, when the AC generating unit 10 does not generate AC current, or generates AC current with a frequency lower than 50 kHz, the heat generation in the bus 20-1 remains unchanged compared to the past, despite the fluctuations in the current waveform associated with normal charging and discharging operations in the vehicle M, the rotation of the electric motor for driving, and the switching of the inverter, etc. Furthermore, it can be seen that in the heating system 1, if the AC generating unit 10 generates AC current with a frequency higher than 50 kHz and applies it to the bus 20-1, the battery 30 can be intentionally heated by the heat generated by the bus 20-1 (more specifically, by the heat generated by the resistor 23). And, as... Figure 5 As shown in (b), the heat generated by bus 20-1 increases with the frequency of current I as the frequency of current I increases when the frequency of current I is higher than 50 [kHz]. Therefore, in the heating system 1, the battery 30 can be effectively heated to the intended temperature.

[0055] [Another structural example of a busbar]

[0056] Figure 6This is a diagram showing another example of the structure of the busbar 20 in the first embodiment. In the following description, the other busbar 20 will be referred to as "busbar 20-2". Like busbar 20-1, busbar 20-2 is mainly formed of a metal conductor 21, and terminal holes A and B are formed at both ends of the metal conductor 21. Furthermore, like busbar 20-1, busbar 20-2 has two current paths, current path P1 and current path P2, between terminal holes A and B. In busbar 20-2, a magnetic element 24 is provided to surround the metal conductor 21 of current path P1. In busbar 20-2, a resistive element 23 is provided on current path P2, similar to busbar 20-1.

[0057] The equivalent circuit of bus 20-2 and Figure 4 The equivalent circuit of busbar 20-1 shown is the same. In busbar 20-2, the resistive component of current path P1 is replaced by the resistive component of the metal conductor 21 itself, and the inductive component is replaced by the inductive component generated by the current flowing (passing through) inside the magnetic body 24. In busbar 20-2, also as in busbar 20-1, when a charging / discharging current flows between terminal hole A and terminal hole B, it flows through the current path P1 with a lower resistance value. Furthermore, in busbar 20-2, also as in busbar 20-1, when an alternating current flows between terminal hole A and terminal hole B, the inductive component generated by the magnetic body 24 suppresses the flow of alternating current to current path P1, and the resistor 23 heats up in response to the alternating current flowing through current path P2.

[0058] With this structure, in busbar 20-2, similar to busbar 20-1, during normal charging and discharging operations of battery 30, the charging and discharging current of battery 30 flows through current path P1. When battery 30 heats up, the alternating current generated by alternating current generator 10 flows through current path P2, generating heat. In busbar 20-2, the relationship between the frequency of the flowing current and the heat generated also considers the case where the frequency of the current I changing in the main heat-generating current path differs, but... Figure 5 The frequency of the current in bus 20-2 shown is equivalent to the heat generated. Therefore, in bus 20-2, as in bus 20-1, in the heating system 1, by generating a high-frequency alternating current in the alternating current generating unit 10 and applying it to bus 20-2, the battery 30 can be intentionally heated by the heating of bus 20-2 (more specifically, by the heating of resistor 23).

[0059] Thus, in the busbar 20 of the first embodiment, an inductive component Ls and a resistive component Rs with a negligible resistance value are provided in the current path P1, and a resistor 23 is provided in the current path P2, wherein the resistance value of the resistive component Rm of the resistor 23 is higher than that of the resistive component Rs. Furthermore, in the first embodiment, during the normal charging and discharging operation of the battery 30, the busbar 20 allows the charging and discharging current to flow in the current path P1 without generating heat, and generates heat in the resistor 23 by allowing the high-frequency alternating current generated by the alternating current generation unit 10 of the heating system 1 to flow in the current path P2. Therefore, in the busbar 20 of the first embodiment, the battery 30 can be intentionally heated.

[0060] <Second Implementation Method>

[0061] [Example of busbar structure]

[0062] Figure 7 This diagram illustrates an example of the structure of the busbar 20 according to the second embodiment. Like the busbars 20-1 and 20-2 of the first embodiment, the busbar 20 of the second embodiment is primarily formed of a metal conductor 21, and terminal holes A and B are formed at both ends of the metal conductor 21. In the busbar 20 of the second embodiment, there is only one current path for current flow between terminal holes A and B. In the following description, this current path in the busbar 20 of the second embodiment will be referred to as "current path P1". In the busbar 20 of the second embodiment, a magnetic body 25 is provided to surround the metal conductor 21 of the current path P1. Figure 7 The diagram shows two examples of different structures in the second embodiment where the busbar 20 is equipped with a magnetic body 25. More specifically, Figure 7 (a) shows a second embodiment of the busbar 20 (hereinafter referred to as "busbar 20-3") with a structure in which a magnetic body 25 is provided to surround a portion of the metal conductor 21 of the current path P1. Figure 7 (b) shows a second embodiment of the busbar 20 (hereinafter referred to as "busbar 20-4") with a structure in which a magnetic body 25 is provided in such a way that the surface of the metal conductor 21 of the current path P1 is covered.

[0063] The magnetic body 25 is a structure that generates heat through the high-frequency magnetic flux passing through its interior when a high-frequency magnetic field (alternating magnetic field) is applied. The material of the magnetic body 25 is, for example, equivalent to magnetic materials called magnetic nanoparticles used in medical fields such as cancer treatment (thermotherapy).

[0064] In busbar 20-3, for example, a magnetic body 25, consisting of magnetic nanoparticles, is formed in close contact with the metal conductor 21. In busbar 20-4, for example, powdered magnetic nanoparticles are mixed with a binder and coated onto the surface of the metal conductor 21. As a result, in busbars 20-3 and 20-4, the magnetic body 25 heats up due to a high-frequency magnetic flux corresponding to a high-frequency magnetic field generated by a high-frequency alternating current flowing between terminal holes A and B. Furthermore, the heat generated by the magnetic body 25 is transferred to the metal conductor 21 in busbars 20-3 and 20-4, thereby increasing the temperature of busbars 20-3 and 20-4 themselves.

[0065] With this structure, under the DC or low-frequency AC current flowing in busbars 20-3 and 20-4 during the normal charging and discharging of the battery 30, the magnetic body 25 does not heat up. However, the high-frequency AC current generated by the AC generator 10 causes the magnetic body 25 to heat up. The relationship between the frequency of the current flowing in busbars 20-3 and 20-4 and the heat generation is... Figure 5 The relationship between the frequency of the current and the heat generation in busbar 20-2 also takes into account the different temperatures and frequencies of the current I, but the heating characteristics of busbars 20-3 and 20-4 are easily confirmed. Therefore, in busbars 20-3 and 20-4, similar to busbars 20-1 and 20-2, in the heating system 1, by generating and applying a high-frequency alternating current in the AC generating unit 10, the battery 30 can be intentionally heated by the heating of busbars 20-3 and 20-4 (more specifically, by the heating of the magnetic body 25).

[0066] Thus, in the busbar 20 of the second embodiment, a magnetic body 25 is provided in the current path P1. Furthermore, in the second embodiment, the magnetic body 25 does not heat up during the normal charging and discharging operation of the battery 30. It heats up by allowing a high-frequency alternating current generated by the alternating current generator 10 of the heating system 1 to flow in the current path P1. Therefore, in the busbar 20 of the second embodiment, the battery 30 can also be intentionally heated.

[0067] <Third Implementation Method>

[0068] [Example of busbar structure]

[0069] Figure 8This diagram illustrates an example of the structure of busbar 20 (hereinafter referred to as "busbar 20-5") according to the third embodiment. Like busbars 20-1 and 20-2 in the first embodiment, and busbars 20-3 and 20-4 in the second embodiment, busbar 20-5 is primarily formed of a metal conductor 21, with terminal holes A and B formed at both ends of the metal conductor 21. In busbar 20-5, a metal conductor 26, for example, with a resistor 23, is connected to the central portion of the metal conductor 21, forming a T-shape. In busbar 20-5, the connection portion between the metal conductor 21 and the metal conductor 26 (i.e., the branch portion branching from the metal conductor 21) is connected in a manner that reduces the thermal resistance between the metal conductor 21 and the resistor 23. A terminal hole C, similar to terminal holes A and B, is formed at the end of the metal conductor 26 opposite to the branch portion. Busbar 20-5 has three current paths: P1 between terminal hole A and terminal hole B, P3 between terminal hole A and terminal hole C, and P4 between terminal hole B and terminal hole C.

[0070] With this structure, in busbar 20-5, during the normal charging and discharging operation of the battery 30, the charging and discharging current of the battery 30 flows through current path P1. When the battery 30 heats up, the alternating current generated by the AC generating unit 10 flows through current path P3 or current path P4, generating heat. In busbar 20-5, unlike busbars 20-1 and 20-2 in the first embodiment, a reactor 22 and a magnetic body 24 are not provided in current path P1. Therefore, during the normal charging and discharging operation of the battery 30, it does not heat up under the action of the charging and discharging current of the battery 30 flowing through current path P1, but the resistive body 23 heats up when the alternating current generated by the AC generating unit 10 flows through current path P3 or current path P4. Therefore, in bus 20-5, similar to bus 20-1 to bus 20-4, in the heating system 1, by generating an alternating current in the alternating current generating unit 10 and applying it to the current path P3 and current path P4 of bus 20-5, the battery 30 can be intentionally heated by the heating of bus 20-5 (more specifically, the heating of resistor 23).

[0071] In busbar 20-5, current path P1 is an example of the "first path" in the technical solution, and current paths P3 and P4 are examples of the "second path" in the technical solution.

[0072] Furthermore, the busbar 20-5 has a T-shaped shape. Therefore, the busbar 20-5 is more suitable as a structure that heats up each individual battery 30, for example, when the battery 30 mounted in the vehicle M is a combination of multiple (e.g., two) batteries 30.

[0073] [Examples of busbar application]

[0074] Figure 9 This is a diagram illustrating an applicable example of busbar 20-5 in the third embodiment. Figure 9 This is an example of connecting busbars 20-5 (busbars 20-5a, 20-5b, and 20-5c) when the battery 30 is a combination of two batteries 30 (battery 30a and battery 30b).

[0075] In the case where the battery 30 is a combination of battery 30a and battery 30b, each battery 30 is connected one by one to an AC generation circuit 12 (AC generation circuit 12a and AC generation circuit 12b), and the control unit 14 controls the generation of AC current in each AC generation circuit 12. That is, the control unit 14 alternately switches the parallel connection and series connection of capacitors C1 and C2 in the AC generation circuit 12 connected to the battery 30 to be heated to the battery 30 side. The switching method of the parallel connection and series connection of capacitors C1 and C2 in the control unit 14, that is, the control method of the on and off states of the switches in each AC generation circuit 12, is used in conjunction with the method of... Figure 2 The control method of the control unit 14 described herein is the same, so a detailed description thereafter is omitted.

[0076] Thus, in the heating system 1, the bus 20-5 corresponding to either or both of the AC generating circuits 12a and 12b that generate AC current, which are controlled by the control unit 14, heats up (more specifically, resistors 23a, 23b, and 23c), thereby intentionally heating up the battery 30 (either or both of battery 30a and 30b) connected to the heated bus 20-5.

[0077] exist Figure 9 In the applicable example of busbar 20-5 shown, battery 30a and battery 30b are examples of "energy storage body" in the technical solution, and the structure of combining battery 30a and battery 30b is an example of "battery" in the technical solution.

[0078] Thus, in the busbar 20 of the third embodiment, a resistor 23 is provided on the metal conductor 26 branching from the metal conductor 21. Therefore, in the busbar 20 of the third embodiment, during the normal charging and discharging operation of the battery 30, the charging and discharging current flows in the current path P1 without generating heat, while the resistor 23 is heated by the alternating current generated by the alternating current generation unit 10 of the heating system 1 flowing in the current path P3 or the current path P4. Therefore, in the busbar 20 of the third embodiment, the battery 30 can also be intentionally heated.

[0079] As described above, the busbar 20 in each embodiment is equipped with a structure that generates heat based on the alternating current generated by the alternating current generating unit 10. Therefore, in the heating system 1 equipped with the busbar 20 of each embodiment, during the normal charging and discharging operation of the battery 30, the charging and discharging current can flow, and the alternating current generated by the alternating current generating unit 10 can intentionally raise the temperature of the battery 30. Furthermore, since the busbar 20 in each embodiment is connected to a terminal portion that has good heat transfer to the entire battery 30, the battery 30 can be heated more effectively. Therefore, in the vehicle M equipped with the heating system 1 equipped with the busbar 20 of each embodiment, the battery 30 can be used at a suitable temperature, and the degradation of the charging and discharging performance of the battery 30 can be suppressed.

[0080] The heating system 1 according to the above-described embodiments includes an AC generating circuit 12 and a bus 20. The AC generating circuit 12 is connected to one or more batteries 30 and generates AC current. The bus 20 is a metal conductor 21 connected between the terminal portion of the battery 30 and the AC generating circuit 12, or between multiple batteries 30. It has a current path P1 and a current path P2 that generates heat by allowing AC current to pass through. The current path P1 has a larger inductance than the current path P2, thereby enabling the battery 30 used for driving in the vehicle M to be intentionally heated. Therefore, in the vehicle M using the heating system 1 of each embodiment, the battery 30 can be used at a suitable temperature, and the degradation of the charging and discharging performance of the battery 30 can be suppressed. Therefore, in the vehicle M equipped with the heating system 1 of each embodiment, improved durability and other improvements can be achieved, thereby enhancing the commercial viability of the vehicle M. Therefore, in the vehicle M equipped with the heating system 1 of each embodiment, energy efficiency can be improved, and it is expected to contribute to mitigating the adverse effects on the Earth's environment.

[0081] In the various embodiments described above, it is explained that the control device such as the ECU of the vehicle M controls the start or stop of the heating system 1, and the control unit 14 of the AC generation unit 10 controls the switches of the AC generation circuit 12 to be in an on or off state. The function of the control device of the vehicle M may also include the function of the control unit 14 described above. In this case, the control unit 14 can be omitted in the heating system 1.

[0082] The embodiments described above illustrate the methods for implementing the present invention, but the present invention is not limited to these embodiments in any way, and various modifications and substitutions can be applied without departing from the spirit of the present invention.

Claims

1. A heating system, wherein, The heating system includes: An AC generating circuit, connected to a battery containing one or more energy storage elements, generates alternating current; and A conductive component is a conductive metal conductor connected between the terminal portion of the energy storage element and the AC generating circuit, or between multiple energy storage elements, and has a first path and a second path that generates heat by allowing the AC current to pass through. The first path has a larger inductive component than the second path. In the conductive component, a first resistive component and an inductive component are provided in the first path. A second resistive component is provided in the second path. The resistance value of the second resistive component is higher than the resistance value of the first resistive component.

2. The heating system according to claim 1, wherein, A reactor having the first resistive component and the said inductive component is provided in the first path. A resistor having the second resistive component is provided in the second path.

3. The heating system according to claim 1, wherein, The first path includes a metal conductor having the first resistive component and a magnetic body surrounding the metal conductor. A resistor having the second resistive component is provided in the second path.

4. The heating system according to any one of claims 1 to 3, wherein, The AC generating circuit has a first capacitor connected at one end to the positive side of the energy storage body and a second capacitor connected at one end to the negative side of the energy storage body. By switching the connection of the first capacitor and the second capacitor to the energy storage body to a series connection or a parallel connection, the AC current is generated by the resonant action of the inductive component of the energy storage body and at least the first capacitor.

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