Heating System

Abstract

To provide a temperature rising system that can rise temperature of a secondary battery when necessary by suppressing heat generation due to current flowing during normal charging and discharging of the secondary battery and generating heat by passing a high-frequency AC current.SOLUTION: A temperature rising system includes: an AC generating circuit that is connected to a storage battery including one or more power storage units and generates AC current; and a conductive member of a metal conductor that is connected between a terminal portion of the power storage unit and the AC generating circuit or between multiple power storage units, the conductive member having a first path and a second path that branches off from the first path and generates heat by passing AC current through it, and a resistor is provided in the second path.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heating system. [Background technology]

[0002] Efforts to reduce adverse effects on the global environment (e.g., reducing NOx, SOx, or CO2) are underway. Therefore, in recent years, from the perspective of improving the global environment and reducing CO2 emissions, there has been growing interest in electric vehicles, such as hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs), which are driven by at least an electric motor powered by a battery (secondary battery). The use of lithium-ion secondary batteries as in-vehicle batteries is being considered. In these electric vehicles, it is important to fully utilize the performance of secondary batteries. It is known that the charge / discharge performance of secondary batteries decreases when the temperature during use drops below a suitable range. The decrease in charge / discharge performance of secondary batteries can be suppressed by raising the temperature to a suitable level during use.

[0003] For example, Patent Documents 1 and 2 disclose techniques for cooling the inside of a battery by cooling the terminals of the battery. Patent Document 1, for example, describes that by abutting a heat dissipation member against the end face of the battery's terminal, the contact area between the terminal and the heat dissipation member is increased, resulting in more efficient heat transfer from the terminal to the heat dissipation member. These conventional techniques utilize the good heat transfer between the battery's terminals and the battery's interior to efficiently dissipate heat from the battery. Therefore, conversely, it is believed that heating the terminals can also efficiently increase the temperature of a secondary battery.

[0004] Meanwhile, for example, Patent Document 3 discloses a technology related to a heating device that heats a secondary battery. The heating device disclosed in Patent Document 3 heats the secondary battery by actively generating in the secondary battery a ripple current of a predetermined frequency in a frequency range where the absolute value of the impedance is relatively low, based on the frequency characteristics of the impedance of the secondary battery. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4940490 [Patent Document 2] Patent No. 5096842 [Patent Document 3] Patent No. 5293820 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, when considering combining conventional technologies to heat a secondary battery, one possible approach is to pass a high-frequency alternating current through a metal member (a heat dissipation member in Patent Documents 1 and 2) that is in contact with the terminals of the secondary battery, thereby causing the metal member to heat up. In this case, in order to pass an alternating current through the metal member and cause it to generate more heat, it is necessary to increase the resistance of the metal member. However, increasing the resistance of the metal member may affect the normal charge / discharge characteristics of the secondary battery. For example, if the metal member heats up due to the current that flows during normal charge / discharge, the secondary battery will heat up even when it does not need to be heated.

[0007] The present invention was made based on the recognition of the above-mentioned problems, and one of its objectives is to provide a heating system that can raise the temperature of a secondary battery when necessary and improve energy efficiency by suppressing heat generation due to the current that flows during normal charging and discharging of the secondary battery while generating heat by passing a high-frequency alternating current through it. [Means for solving the problem]

[0008] The heating system according to the present invention employs the following configuration. (1): A heating system according to one embodiment of the present invention includes an AC generating circuit connected to a storage battery including one or more power storage units and generating an AC current, and a conductive member made of a metal conductor connected between a terminal portion of the power storage unit and the AC generating circuit or between a plurality of the power storage units, the conductive member having a first path and a second path branching from the first path and generating heat by passing the AC current through the conductive member, the second path having a resistor provided therein.

[0009] (2): In the above aspect (1), the AC generating circuit has a first capacitor having one end connected to the positive electrode side of the power storage unit and a second capacitor having one end connected to the negative electrode side of the power storage unit, and by switching the connection of the first capacitor and the second capacitor to the power storage unit between a series connection and a parallel connection, the AC current is generated by the resonance operation of the inductance component of the power storage unit and at least the first capacitor. [Effects of the Invention]

[0010] According to the above-mentioned aspects (1) and (2), heat generation due to current flowing during normal charging and discharging of the secondary battery is suppressed, while heat generation is generated by flowing a high-frequency alternating current, thereby making it possible to raise the temperature of the secondary battery when necessary and improve energy efficiency. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating an example of the configuration of a heating system according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of an AC generating circuit included in the heating system. [Figure 3] 3A and 3B are diagrams illustrating an example of the structure of a bus bar according to the first embodiment. [Figure 4]3 is an example of an equivalent circuit of the bus bar according to the first embodiment. [Figure 5] FIG. 4 is a diagram illustrating an example of heat generation characteristics of the bus bar according to the first embodiment. [Figure 6] 5A and 5B are diagrams illustrating another example of the structure of the bus bar according to the first embodiment. [Figure 7] 10A and 10B are diagrams illustrating an example of the structure of a bus bar according to a second embodiment. [Figure 8] 10A and 10B are diagrams illustrating an example of the structure of a bus bar according to a third embodiment. [Figure 9] 10A and 10B are diagrams illustrating an application example of the bus bar according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of a heating system of the present invention will be described with reference to the drawings.

[0013] [Heating system configuration] Fig. 1 is a diagram showing an example of the configuration of a temperature raising system according to an embodiment. The temperature raising system 1 includes, for example, an AC generating unit 10 including an AC generating circuit 12, and a bus bar 20. Fig. 1 also shows a battery 30 whose temperature is raised in the temperature raising system 1. Fig. 1 shows a state in which bus bars 20 (bus bar 20a and bus bar 20b) are connected to the terminal portions of the positive and negative sides of the battery 30.

[0014] The battery 30 is a battery (secondary battery) for driving a hybrid electric vehicle (HEV) (hereinafter simply referred to as "vehicle M") that runs by, for example, driving an electric motor using supplied electric power or by driving an internal combustion engine that uses fuel such as a diesel engine or a gasoline engine as an energy source. The battery 30 includes, as an electric storage unit Ba, a secondary battery that can be repeatedly charged and discharged, such as a lithium-ion battery. The battery 30 discharges electric power stored in the electric storage unit Ba and supplies it to an electric motor connected to terminals V0 and V1. For example, the electric motor operates as a regenerative brake using kinetic energy during deceleration of the vehicle M to generate electric power, and charges the electric power supplied from terminals V0 and V1. The battery 30 is an example of a "power storage unit" or "storage battery" in the claims.

[0015] The heating system 1 raises (heats) the temperature of the battery 30 to a temperature suitable for use in order to suppress a decrease in the charge / discharge performance of the battery 30. The activation and stop of the heating system 1 is controlled by, for example, a control device such as an ECU (Electronic Control Unit) provided in the vehicle M.

[0016] The AC generating unit 10 generates a high-frequency AC current using the AC generating circuit 12 to heat the busbar 20. The busbar 20 is a conductive member formed primarily of a metal conductor such as copper. The busbar 20 is connected to the terminals of the battery 30. During normal charging and discharging of the battery 30, the busbar 20 passes a current (charge / discharge current) between the battery 30 and terminals V0 and V1. The charge / discharge current is a direct current or an AC current with a lower frequency than the AC current generated by the AC generating unit 10. When the AC current generated by the AC generating unit 10 is applied (flowed) to the battery 30, the battery 30 generates heat in response to the AC current. The heat generated by the busbar 20 is transferred to the terminals of the battery 30, and the heat is further transferred to the interior of the battery 30, causing the temperature of the battery 30 to rise. This is because the terminals of the battery 30 are connected to the interior of the battery 30 by a metal material, which allows for good heat transfer throughout the battery 30. The bus bar 20 is an example of the "conductive member" in the claims.

[0017] [Configuration example of AC generating section] Fig. 2 is a diagram showing an example of the configuration of an AC generating unit 10 included in the temperature raising system 1. The AC generating unit 10 includes, for example, an AC generating circuit 12 and a control unit 14. Fig. 2 also shows bus bars 20 (bus bars 20a and 20b) and a battery 30 included in the temperature raising system 1. The battery 30 has, for example, a resistance Ra and an inductance La connected in series to the positive electrode side of a power storage unit Ba. The inductance La is an example of an "inductance component possessed by a power storage unit" in the claims.

[0018] The AC generating circuit 12 includes, for example, a capacitor C1, a capacitor C2, a switch S1, a switch S2, and a switch S3. The capacitors C1 and C2 have the same capacitance. The switches S1, S2, and S3 are each controlled to a conductive state in which both terminals are connected (closed state) or a non-conductive state in which both terminals are not connected (open state) in response to a control signal output from the control unit 14. The switches S1, S2, and S3 may each be a semiconductor switching element that is controlled to be either on or off, such as an N-channel metal oxide semiconductor field effect transistor (MOSFET).

[0019] In the AC generating circuit 12, a first terminal of the capacitor C1 is connected to the positive electrode side of the battery 30, and a first terminal of the capacitor C2 is connected to the negative electrode side of the battery 30. Furthermore, in the AC generating circuit 12, a first terminal of the switch S2 is connected to the first terminal of the capacitor C1, and a second terminal of the switch S1 is connected to the first terminal of the capacitor C2. In the AC generating circuit 12, a first terminal of the switch S1 and a second terminal of the switch S3 are connected to the second terminal of the capacitor C1, and a second terminal of the capacitor C2 is connected to the second terminal of the switch S2 and a first terminal of the switch S3. In the AC generating circuit 12, the capacitor C1 is an example of a "first capacitor" in the claims, and the capacitor C2 is an example of a "second capacitor" in the claims.

[0020] When the temperature raising system 1 is started, the control unit 14 switches the connection of capacitors C1 and C2 to the battery 30 side between a parallel connection or a series connection by turning on or off each switch 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 on switch S3, and a state in which capacitors C1 and C2 are connected in series to the battery 30 side by turning on switches S1 and S2 and turning on switch S3.

[0021] The control unit 14 operates by, for example, a hardware processor such as a CPU (Central Processing Unit) executing a program (software). The control unit 14 may be realized by hardware (including circuitry) such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a GPU (Graphics Processing Unit), or may be realized by a combination of software and hardware. The control unit 14 may be realized by a dedicated LSI. The program may be stored in advance in a storage device (a storage device having a non-transitory storage medium) such as a flash memory included in the AC generating unit 10.

[0022] The AC generating circuit 12 generates an AC current by resonating with at least the capacitor C1 and the inductance La of the battery 30, as a result of the control unit 14 switching the connection of the capacitors C1 and C2 to the battery 30 side between a parallel connection and a series connection. More specifically, the AC generating circuit 12 generates a high-frequency AC current based on the power stored in the battery 30 by resonating with at least the capacitor C1, which alternately exchanges magnetic energy stored in the inductance La of the battery 30 with electrostatic energy stored in at least the capacitor C1.

[0023] The AC generating unit 10 applies (passes) the AC current generated by the AC generating circuit 12 to the bus bar 20, thereby causing the bus bar 20 to generate heat and raising the temperature of the battery 30.

[0024] First Embodiment [Example of busbar structure] 3 is a diagram showing an example of the structure of a 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 to which a terminal portion of the battery 30, a terminal for outputting AC current from the AC generating unit 10, a terminal for supplying power to the vehicle M, etc. can be connected. 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 the current path P1, and a resistor 23 is provided in the current path P2.

[0025] The reactor 22 is, for example, a reactor for large currents, having a resistance component and an inductance component. The resistance value of the resistance component of the reactor 22 is so low that it can be ignored. The resistor 23 is a resistor whose resistance value is higher than the resistance value of the resistance component of the reactor 22. It is conceivable that the resistor 23 also includes an inductance component, but the inductance component of the resistor 23 is so small that it can be ignored.

[0026] With this configuration, in the bus bar 20-1, the charging / discharging current of the battery 30 flows via the current path P1 during normal charging / discharging operations of the battery 30. On the other hand, when the temperature of the battery 30 is raised by the bus bar 20-1, the AC current generated by the AC generating unit 10 flows via the current path P2.

[0027] In the busbar 20-1, the current path P1 is an example of a "first path" in the claims, and the current path P2 is an example of a "second path" in the claims.

[0028] FIG. 4 shows an example of an equivalent circuit of the busbar 20-1 according to the first embodiment. In FIG. 4, the resistance component of the reactor 22 is designated "Rs" and the inductance component is designated "Ls." In FIG. 4, the resistance component of the resistor 23 is designated "Rm." When a charge / discharge current flows between terminal holes A and B, the busbar 20-1 passes through a current path P1 with a lower resistance value, with characteristics corresponding to the resistance component Rs and inductance component Ls of the reactor 22. On the other hand, when an AC current flows between terminal holes A and B, the high-frequency AC current is prevented from flowing through the current path P1 by the inductance component Ls of the reactor 22. Instead, the high-frequency AC current flows through a current path P2 with a higher resistance value, with characteristics corresponding to the resistance component Rm of the resistor 23. As a result, the resistor 23 in the busbar 20-1 generates heat in response to the AC current flowing through it.

[0029] In busbar 20-1, resistance component Rs is an example of a "first resistance component" in the claims, inductance component Ls is an example of an "inductance component" in the claims, and resistance component Rm is an example of a "second resistance component" in the claims.

[0030] Here, the relationship between the frequency of the current flowing through the busbar 20-1 and the amount of heat generated will be described. FIG. 5 is a diagram illustrating an example of the heat generation characteristics of the busbar 20-1 of the first embodiment. FIG. 5(a) illustrates an example circuit in which the power supply PS applies currents of the same current value but different frequencies to the equivalent circuit of the busbar 20-1 shown in FIG. 4. FIG. 5(b) illustrates an example of the changes in the current flowing through each current path and the amount of heat generated with respect to frequency in the example circuit shown in FIG. 5(a). More specifically, FIG. 5(b) illustrates the changes in the frequency of the current I1 flowing through the current path P1, the current I2 flowing through the current path P2, the amount of heat generated in the current path P1, the amount of heat generated in the current path P2, and the overall amount of heat generated by the busbar 20-1. FIG. 5(a) illustrates an example of the directions in which the currents I1 and I2 flow. The example shown in Figure 5 is an example when a power supply PS applies a sinusoidal current I with a current amplitude of 20 [A] to a bus bar 20-1 in which the inductance component Ls of the reactor 22 is 100 [nH], the resistance component Rs is 1 [mΩ], and the resistance component Rm of the resistor 23 is 1 [Ω].

[0031] As shown in the lower part of FIG. 5B, when the power supply PS applies a current I having a frequency of, for example, 50 kHz or less to the busbar 20-1, a current I1 corresponding to the applied current I flows through the current path P1, but almost no current I2 flows through the current path P2 due to the resistor 23. Therefore, as shown in the middle part of FIG. 5B, when a current I having a frequency of 50 kHz or less is applied, the heat generation amount W1 in the current path P1 through which the current I1 flows is the main heat generation amount, and the heat generation amount W2 in the current path P2 is almost negligible. Therefore, as shown in the upper part of FIG. 5B, the total heat generation amount of the busbar 20-1 is the heat generation amount corresponding to the heat generation amount W1. In other words, when a current I having a frequency of 50 kHz or less is applied, the busbar 20-1 generates almost no heat.

[0032] In contrast, as shown in the lower part of FIG. 5B, when the power supply PS applies current I having a frequency exceeding 50 kHz to the busbar 20-1, the amount of current I2 flowing through the current path P2 gradually increases as the frequency increases. In contrast, in the current path P1, as the frequency of the current I increases further, the amount of current I1 gradually decreases. Therefore, as shown in the middle part of FIG. 5B, the current path that primarily generates heat changes when the frequency exceeds 50 kHz. More specifically, in the current path P1, the inductance component Ls of the reactor 22 suppresses the flow of current I having a frequency exceeding 50 kHz. As a result, the amount of heat generated W1 in the current path P1 remains unchanged. However, the amount of heat generated W2 in the current path P2, which includes the resistor 23 with a high resistance, increases as the frequency increases, and becomes the main source of heat in the busbar 20-1 when the frequency exceeds 50 kHz. Therefore, as shown in the upper part of FIG. 5(b), the total heat generation amount of the bus bar 20-1 gradually increases from the point where the frequency reaches approximately 50 [kHz].

[0033] In this way, busbar 20-1 has heat generation characteristics in which when the frequency of the applied current I is 50 kHz or less, the heat generation amount W1 in current path P1 is dominant, and when the frequency exceeds 50 kHz, the heat generation amount W2 in current path P2 is dominant.

[0034] Generally, in the vehicle M, the frequency of the current accompanying the charging and discharging of the battery 30 is DC to several Hz. The frequency of the current fluctuation (so-called ripple in the current waveform) accompanying the rotation of the electric motor for driving is limited to several kHz. Furthermore, the frequency of the ripple in the current waveform due to switching of, for example, an inverter mounted on the vehicle M is limited to several tens of kHz.

[0035] From this, it can be seen that in the temperature-raising 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 busbar 20-1 is the same as in the conventional system when the AC generating unit 10 generates an AC current with a frequency higher than 50 kHz and applies it to the busbar 20-1, and the busbar 20-1 generates an AC current with a frequency higher than 50 kHz. Furthermore, it can be seen that in the temperature-raising system 1, when the AC generating unit 10 generates an AC current with a frequency higher than 50 kHz and applies it to the busbar 20-1, the heat generation in the busbar 20-1 (more specifically, the heat generation in the resistor 23) can be used to intentionally raise the temperature of the battery 30. Moreover, as shown in FIG. 5(b), when the current I has a frequency higher than 50 kHz, the amount of heat generated in the busbar 20-1 increases as the frequency of the current I increases. Therefore, the temperature-raising system 1 can efficiently raise the temperature of the battery 30 to an intended temperature.

[0036] [Another example of a busbar structure] FIG. 6 is a diagram showing another example of the structure of the busbar 20 of the first embodiment. In the following description, this busbar 20 will be referred to as "busbar 20-2." Like the busbar 20-1, the busbar 20-2 is also formed mainly of a metal conductor 21, with terminal holes A and B formed at both ends of the metal conductor 21. Like the busbar 20-1, the busbar 20-2 also has two current paths, P1 and P2, between the terminal holes A and B. In the busbar 20-2, a magnetic body 24 is provided so as to surround the periphery of the metal conductor 21 of the current path P1. Like the busbar 20-1, a resistor 23 is provided in the current path P2 of the busbar 20-2.

[0037] The equivalent circuit of busbar 20-2 is the same as the equivalent circuit of busbar 20-1 shown in Figure 4. In busbar 20-2, the resistance component of current path P1 is replaced by the resistance component of metal conductor 21 itself, and the inductance component is replaced by an inductance component generated by current flowing (passing) inside the area surrounded by magnetic body 24. In busbar 20-2, as in busbar 20-1, when a charging / discharging current flows between terminal hole A and terminal hole B, the current flows via current path P1, which has a lower resistance value. In busbar 20-2, as in busbar 20-1, when an AC current flows between terminal hole A and terminal hole B, the flow of the AC current to current path P1 is suppressed by the inductance component generated by magnetic body 24, and resistor 23 generates heat in response to the AC current flowing via current path P2.

[0038] With this configuration, in the busbar 20-2, as in the busbar 20-1, during normal charging and discharging operations of the battery 30, the charging and discharging current of the battery 30 flows via current path P1, and when the temperature of the battery 30 is to be increased, the AC current generated by the AC generating unit 10 flows via current path P2, generating heat. In the busbar 20-2, the relationship between the frequency of the current flowing and the amount of heat generated is equivalent to the relationship between the frequency of the current and the amount of heat generated in the busbar 20-2 shown in FIG. 5, although the frequency of the current I that mainly switches the current path that generates heat may differ. Therefore, in the busbar 20-2, as in the busbar 20-1, the AC generating unit 10 generates a high-frequency AC current and applies it to the busbar 20-2 in the temperature-raising system 1, thereby intentionally increasing the temperature of the battery 30 by the heat generated by the busbar 20-2 (more specifically, the heat generated by the resistor 23).

[0039] As described above, in the busbar 20 of the first embodiment, the current path P1 is provided with an inductance component Ls and a resistance component Rs with a negligibly low resistance, and the current path P2 is provided with a resistor 23 with a resistance component Rm higher than the resistance component Rs. During normal charging and discharging operations of the battery 30, the busbar 20 of the first embodiment does not generate heat by passing a charging / discharging current through the current path P1, but generates heat by passing a high-frequency AC current generated by the AC generating unit 10 of the temperature raising system 1 through the current path P2. As a result, the busbar 20 of the first embodiment can intentionally raise the temperature of the battery 30.

[0040] Second Embodiment [Example of busbar structure] FIG. 7 is a diagram illustrating an example of the structure of a busbar 20 according to the second embodiment. Like the busbars 20-1 and 20-2 according to the first embodiment, the busbar 20 according to the second embodiment is formed primarily of a metal conductor 21, with terminal holes A and B formed at both ends of the metal conductor 21. In the busbar 20 according to the second embodiment, there is one current path through which a current flows between terminal holes A and B. In the following description, this one current path in the busbar 20 according to the second embodiment is referred to as "current path P1." In the busbar 20 according to the second embodiment, a magnetic body 25 is provided to surround the periphery of the metal conductor 21 of the current path P1. FIG. 7 illustrates two examples of the busbar 20 according to the second embodiment, each with a different structure, in which a magnetic body 25 is provided. More specifically, (a) of Figure 7 shows a second embodiment of a busbar 20 (hereinafter referred to as "busbar 20-3") having a structure in which a magnetic body 25 is provided so as to surround a portion of the metal conductor 21 of the current path P1, and (a) of Figure 7 shows a second embodiment of a busbar 20 (hereinafter referred to as "busbar 20-4") having a structure in which a magnetic body 25 is provided so as to cover the surface of the metal conductor 21 of the current path P1.

[0041] When a high-frequency magnetic field (AC magnetic field) is applied to the magnetic body 25, the magnetic body 25 generates heat due to the high-frequency magnetic flux passing through the interior of the magnetic body 25. The material of the magnetic body 25 is equivalent to a magnetic material called magnetic nanoparticles, which is used in the medical field for cancer treatment (hyperthermia treatment), for example.

[0042] In busbar 20-3, for example, magnetic material 25 made of magnetic nanoparticles is formed in close contact with metal conductor 21. In busbar 20-4, for example, powdered magnetic nanoparticles are mixed with a binder and applied to the surface of metal conductor 21. As a result, in busbar 20-3 and busbar 20-4, magnetic material 25 itself generates heat due to high-frequency magnetic flux corresponding to a high-frequency magnetic field generated by a high-frequency AC current flowing (passing) between terminal hole A and terminal hole B. Then, in busbar 20-3 and busbar 20-4, the heat generated by magnetic material 25 is transferred to metal conductor 21, causing the temperature of busbar 20-3 itself and busbar 20-4 itself to rise.

[0043] With this configuration, the magnetic material 25 of the busbars 20-3 and 20-4 does not generate heat when a direct current or a low-frequency alternating current flows during normal charging and discharging of the battery 30. Instead, the magnetic material 25 generates heat when the high-frequency alternating current generated by the alternating current generating unit 10 generates heat. The relationship between the frequency of the current flowing through the busbars 20-3 and 20-4 and the amount of heat generated may differ from the relationship between the frequency of the current flowing through the busbar 20-2 shown in FIG. 5 in terms of the temperature at which heat is generated and the frequency of the current I. However, it is easy to confirm the heat generation characteristics of the busbars 20-3 and 20-4. Therefore, in the busbars 20-3 and 20-4, as in the case of the busbars 20-1 and 20-2, the alternating current generating unit 10 generates and applies a high-frequency alternating current in the temperature-raising system 1, thereby intentionally raising the temperature of the battery 30 by generating heat from the busbars 20-3 and 20-4 (more specifically, by generating heat from the magnetic material 25).

[0044] As described above, in the busbar 20 of the second embodiment, the magnetic body 25 is provided in the current path P1. In the busbar 20 of the second embodiment, the magnetic body 25 does not generate heat during normal charging and discharging operations of the battery 30, but generates heat when a high-frequency AC current generated by the AC generating unit 10 included in the temperature-raising system 1 is passed through the current path P1. As a result, the busbar 20 of the second embodiment can also intentionally raise the temperature of the battery 30.

[0045] Third Embodiment [Example of busbar structure] FIG. 8 is a diagram showing an example of the structure of a busbar 20 (hereinafter referred to as "busbar 20-5") according to a third embodiment. Like the busbars 20-1 and 20-2 according to the first embodiment and the busbars 20-3 and 20-4 according to the second embodiment, the busbar 20-5 is mainly formed of a metal conductor 21, with terminal holes A and B formed at both ends of the metal conductor 21. In the busbar 20-5, a metal conductor 26 provided with a resistor 23 is connected to, for example, the center of the metal conductor 21, forming a T-shape as a whole. In the busbar 20-5, the connection portion between the metal conductor 21 and the metal conductor 26 (i.e., the branch portion from the metal conductor 21) is connected in such a way that the thermal resistance between the metal conductor 21 and the resistor 23 is reduced. A terminal hole C similar to terminal holes A and B is formed at the end of the metal conductor 26 opposite the branch portion. Busbar 20-5 has three current paths: current path P1 between terminal hole A and terminal hole B, current path P3 between terminal hole A and terminal hole C, and current path P4 between terminal hole B and terminal hole C.

[0046] With this configuration, in the busbar 20-5, the charging / discharging current of the battery 30 flows through the current path P1 during normal charging / discharging operations of the battery 30, and when the temperature of the battery 30 is to be increased, the AC current generated by the AC generating unit 10 flows through the current path P3 or the current path P4, thereby generating heat. In the busbar 20-5, unlike the busbars 20-1 and 20-2 of the first embodiment, the reactor 22 and the magnetic body 24 are not provided on the current path P1. Therefore, the charging / discharging current of the battery 30 that flows through the current path P1 during normal charging / discharging operations of the battery 30 does not generate heat, but the resistor 23 generates heat when the AC current generated by the AC generating unit 10 flows through the current path P3 or the current path P4. Therefore, in the case of busbar 20-5, as in the case of busbars 20-1 to 20-4, in the temperature-raising system 1, the AC generating unit 10 generates an AC current and applies it to current path P3 and current path P4 of busbar 20-5, thereby intentionally raising the temperature of battery 30 by heat generation from busbar 20-5 (more specifically, heat generation from resistor 23).

[0047] In the bus bar 20-5, the current path P1 is an example of a "first path" in the claims, and the current paths P3 and P4 are examples of a "second path" in the claims.

[0048] Moreover, the bus bar 20-5 has a T-shape. Therefore, when the battery 30 mounted on the vehicle M is configured by combining a plurality of (for example, two) batteries 30, the bus bar 20-5 can be more easily applied as a configuration for raising the temperature of each battery 30 individually.

[0049] [Application examples of busbars] Fig. 9 is a diagram illustrating an application example of bus bar 20-5 of the third embodiment. Fig. 9 illustrates an example in which bus bar 20-5 (bus bar 20-5a, bus bar 20-5b, and bus bar 20-5c) are connected when battery 30 is configured by combining two batteries 30 (battery 30a and battery 30b).

[0050] When the battery 30 is configured by combining the battery 30a and the battery 30b, one AC generating circuit 12 (AC generating circuit 12a and AC generating circuit 12b) is connected to each battery 30, and the control unit 14 controls the generation of AC current in each AC generating circuit 12. That is, the control unit 14 alternates between parallel connection and series connection to the battery 30 side of the capacitors C1 and C2 included in the AC generating circuit 12 to which the battery 30 whose temperature is to be increased is connected. The method by which the control unit 14 switches between parallel connection and series connection of the capacitors C1 and C2, i.e., the method by which the control unit 14 controls the conductive state and non-conductive state of the switches included in each AC generating circuit 12, is the same as the control method by the control unit 14 described using FIG. 2, and therefore a detailed description thereof will be omitted.

[0051] As a result, in the temperature-raising system 1, the busbar 20-5 corresponding to either or both of the AC generating circuit 12a and the AC generating circuit 12b, in which the control unit 14 generates an AC current, generates heat (more specifically, the resistors 23a, 23b, and 23c generate heat), and the battery 30 (either or both of the battery 30a and the battery 30b) to which the heated busbar 20-5 is connected can be intentionally heated.

[0052] In the application example of busbar 20-5 shown in Figure 9, battery 30a and battery 30b are an example of a "storage battery" in the claims, and the combined configuration of battery 30a and battery 30b is an example of a "storage battery" in the claims.

[0053] As described above, in the busbar 20 of the third embodiment, the resistor 23 is provided on the metal conductor 26 branching off from the metal conductor 21. As a result, in the busbar 20 of the third embodiment, during normal charging and discharging operations of the battery 30, the charge / discharge current flows through the current path P1, and heat is not generated, but the AC current generated by the AC generating unit 10 included in the temperature raising system 1 flows through the current path P3 or P4, causing the resistor 23 to heat up. As a result, the busbar 20 of the third embodiment can also intentionally raise the temperature of the battery 30.

[0054] As described above, the busbar 20 of each embodiment is configured to generate heat in response to the AC current generated by the AC generating unit 10. As a result, the heating system 1 including the busbar 20 of each embodiment can pass a charge / discharge current during normal charging and discharging operations of the battery 30, and can intentionally heat the battery 30 by having the AC generating unit 10 generate an AC current. Moreover, the busbar 20 of each embodiment is connected to a terminal portion of the battery 30 that has good heat transfer to the entire battery 30, so the temperature of the battery 30 can be raised more efficiently. As a result, in a vehicle M employing the heating system 1 including the busbar 20 of each embodiment, the battery 30 can be used in a state where it has been heated to a suitable temperature, and deterioration in the charge / discharge performance of the battery 30 can be suppressed.

[0055] The heating system 1 of each of the above-described embodiments includes an AC generating circuit 12 connected to one or more batteries 30 and generating an AC current, and a busbar 20 made of a metal conductor 21 connected between a terminal portion of the battery 30 and the AC generating circuit 12 or between multiple batteries 30. The busbar 20 has a current path P1 and a current path P2 that generates heat by passing an AC current, and the current path P1 has a larger inductance component than the current path P2. This allows the vehicle M equipped with the heating system 1 of each of the embodiments to intentionally heat the battery 30 used for driving the vehicle M. As a result, the vehicle M equipped with the heating system 1 of each of the embodiments can use the battery 30 in a state where the battery 30 has been heated to a suitable temperature, thereby suppressing deterioration in the charge / discharge performance of the battery 30. This improves the marketability of the vehicle M, such as by improving durability. As a result, the vehicle M equipped with the heating system 1 of each of the embodiments is expected to improve energy efficiency and contribute to reducing adverse effects on the global environment.

[0056] In each of the above-described embodiments, a configuration has been described in which a control device such as an ECU provided in the vehicle M controls the start or stop of the heating system 1, and the control unit 14 provided in the AC generating unit 10 controls each switch provided in the AC generating circuit 12 to a conductive state or a non-conductive state. The functions of the control device provided in the vehicle M may include the functions of the control unit 14 described above. In this case, the control unit 14 may be omitted from the heating system 1.

[0057] The above describes the form for carrying out the present invention using an embodiment, but the present invention is not limited to such an embodiment, and various modifications and substitutions can be made within the scope that does not deviate from the gist of the present invention. [Explanation of symbols]

[0058] 1. Heating system 10,10-2...AC generating section 12, 12a, 12b...AC generating circuit 14. Control section 20, 20a, 20b, 20-1, 20-2, 20-3, 20-4, 20-5, 20-5a, 20-5b, 20-5c... Busbar 21 Metal conductor 22 Reactor 23,23a,23b,23c...Resistor 24...Magnetic material 25...Magnetic material 26 Metal conductor 30, 30a, 30b battery C1, C1a, C1b... Capacitors C2, C2a, C2b... Capacitors S1, S1a, S1b, S2, S2a, S2b... switches S3, S3a, S3b switches P1...current path P2, P3, P4...current path Rs...Resistance component Ls: Inductance component Rm...resistance component

Claims

1. an AC generating circuit connected to a storage battery including one or more power storage units and configured to generate an AC current; a conductive member made of a metal conductor connected between a terminal portion of the power storage unit and the AC generating circuit or between a plurality of the power storage units, a first pathway; and a conductive member having a second path branched from the first path and generating heat by passing the AC current therethrough, the second path being provided with a resistor; A heating system comprising:

2. The AC generating circuit comprises: a first capacitor having one end connected to the positive electrode side of the power storage unit and a second capacitor having one end connected to the negative electrode side of the power storage unit, and by switching the connection of the first capacitor and the second capacitor to the power storage unit between a series connection and a parallel connection, the AC current is generated by a resonance operation between an inductance component of the power storage unit and at least the first capacitor; The heating system of claim 1 .

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