Electricity storage system

Abstract

Provided is a power storage system capable of efficiently charging in accordance with the voltage state of a charging device and capable of reducing manufacturing costs. A power storage system is provided with: a storage battery that can be charged at 400 V, 800 V, and 1200 V; a three-phase motor that is driven by the power supplied from the battery and that has three-phase coils connected to a neutral point; an inverter connected to a power supply circuit of the storage battery and the three-phase motor; and a DC power supply circuit connected to a power transmission path between the inverter and the storage battery. The DC power supply circuit on the positive electrode side has a branch circuit connected to the coil of any one of the three-phase coils via a third connection section. The branch circuit is connected to the auxiliary machine drive circuit via the fourth switch unit via the fourth connection unit. In the auxiliary machine drive circuit, a fifth switch portion is provided between the second connection portion and the fourth connection portion.

Description

Technical Field

[0001] This invention relates to energy storage systems. Background Technology

[0002] In recent years, in order to ensure that more people have access to affordable, reliable and sustainable modern energy, research and development are underway to develop charging and power supply systems for mobile vehicles equipped with secondary batteries that can help improve energy efficiency.

[0003] Regarding the charging power supply in mobile vehicles equipped with secondary batteries, charging equipment such as charging piles comes in two types: 400V (with a maximum voltage of 500V) and 800V (with a maximum voltage of 1000V). If the mobile vehicle only supports 400V charging equipment, it cannot enjoy the fast charging performance of 800V charging equipment.

[0004] When a mobile vehicle supports both 400V and 800V charging equipment, a voltage converter is typically used to boost the voltage to 800V when charging with a 400V charging device, or a voltage converter is used to step the voltage down to 400V when charging with an 800V charging device. However, using a charging voltage converter directly during charging degrades efficiency.

[0005] Regarding this problem, it is known that some mobile vehicles can be charged using both 400V and 800V charging equipment by switching the connection method of the battery module, even without using a voltage converter for charging (e.g., Patent Document 1, Patent Document 2).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2019-080474

[0009] Patent Document 2: Japanese Patent Application Publication No. 2020-150618 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] On the other hand, auxiliary equipment used in mobile vehicles also comes in two types: those driven by 400V and those driven by 800V. In mobile vehicles that switch battery module connection methods, when a 400V auxiliary equipment is driven while being charged using an 800V charging device, or vice versa, a voltage converter for the auxiliary equipment is generally used for voltage conversion. However, voltage converters for auxiliary equipment are expensive, increasing manufacturing costs.

[0012] Furthermore, in recent years, high-voltage and low-current charging methods have been proposed to reduce the burden on the power distribution and terminals of charging systems for mobile vehicles. In 1200V-class charging equipment with an upper voltage limit of 1500V, the burden on the power distribution and terminals of the charging system can be reduced compared to 400V-class and 800V-class charging equipment. For example, theoretically, with a charging equipment output of 320kW, a 400V-class charging equipment can carry 800A of current, while an 800V-class charging equipment can carry 400A of current. On the other hand, in 1200V-class charging equipment, the current can be reduced to 265A.

[0013] Thus, in mobile vehicles that can be charged even when using charging devices with different upper voltage limits by switching the connection method of the battery module, a power storage system that can enable the auxiliary machine to operate without using an expensive voltage converter for the auxiliary machine is desired.

[0014] This invention provides an energy storage system that can efficiently charge according to the voltage state of the charging device and reduce manufacturing costs.

[0015] Methods for solving problems

[0016] The energy storage system of the present invention comprises:

[0017] A storage battery has multiple energy storage units and a switching group. The switching group can switch between a first voltage state that can be charged with a first voltage, a second voltage state that can be charged with a second voltage that is higher than the first voltage, and a third voltage state that can be charged with a third voltage that is higher than the second voltage by switching the connection state of the multiple energy storage units.

[0018] A three-phase motor having three-phase coils connected at a neutral point, driven by power supplied from the battery;

[0019] An inverter is connected to the power transmission path between the battery and the three-phase motor;

[0020] A DC power supply circuit is connected to a first connection point located on the power transmission path between the inverter and the battery;

[0021] Auxiliary equipment, which is capable of being driven using DC power from the battery and an external power source; and

[0022] An auxiliary machine drive circuit, which is connected to a second connection point located on the power transmission path between the inverter and the first connection point, supplies power to the auxiliary machine.

[0023] The DC power supply circuit on the positive side has a branch circuit that is connected to the coil of any one of the three phases of the coil at the third connection point.

[0024] The branch circuit is connected to the auxiliary machine drive circuit at the fourth connection point via a first switching switch.

[0025] In the auxiliary machine drive circuit, a second switching switch is provided between the second connection part and the fourth connection part.

[0026] Invention Effects

[0027] According to the present invention, charging can be performed efficiently based on the voltage state of the charging device, and manufacturing costs can be reduced. Attached Figure Description

[0028] Figure 1 This is a diagram showing the structure of the energy storage system 1 according to the first embodiment.

[0029] Figure 2 This is a diagram showing the structure of battery 2.

[0030] Figure 3 It means Figure 1 A diagram showing the structure of the inverter 5 in the energy storage system 1.

[0031] Figure 4 This is a diagram showing the first voltage state (400V startup state) of battery 2.

[0032] Figure 5 This is a diagram showing the second voltage state (800V startup state) of battery 2.

[0033] Figure 6 This is a diagram showing the third voltage state (1200V startup state) of battery 2.

[0034] Figure 7 This is a diagram showing the flow of current when an electric vehicle equipped with the energy storage system 1 of the first embodiment is in motion.

[0035] Figure 8 This is a diagram showing the flow of current when the electric vehicle equipped with the energy storage system 1 of the first embodiment is charged with the first voltage (400V).

[0036] Figure 9 This is a diagram illustrating the boost operation of inverter 5.

[0037] Figure 10 This is a diagram illustrating the boost operation of inverter 5.

[0038] Figure 11This is a diagram showing the current flow when the electric vehicle equipped with the energy storage system 1 of the first embodiment is charged with the second voltage (800V).

[0039] Figure 12 This is a diagram showing the current flow when the electric vehicle equipped with the energy storage system 1 of the first embodiment is charged with the third voltage (1200V).

[0040] Figure 13 This is a diagram illustrating the step-down operation of inverter 5.

[0041] Figure 14 This is a diagram illustrating the step-down operation of inverter 5.

[0042] Figure 15 It is a table that summarizes the states of switches and contactors in each mode of the energy storage system 1 of the first embodiment.

[0043] Figure 16 This is a flowchart representing the control process of the energy storage system 1.

[0044] Figure 17 This is a diagram showing the structure of the energy storage system 1 according to the second embodiment.

[0045] Figure 18 This is a diagram showing the flow of current when an electric vehicle equipped with the energy storage system 1 of the second embodiment is in motion.

[0046] Figure 19 This is a diagram showing the flow of current when the electric vehicle equipped with the energy storage system 1 of the second embodiment is charged with the first voltage (400V).

[0047] Figure 20 This is a diagram showing the flow of current when the electric vehicle equipped with the energy storage system 1 of the second embodiment is charged with the second voltage (800V).

[0048] Figure 21 This is a diagram showing the current flow when the electric vehicle equipped with the energy storage system 1 of the second embodiment is charged with the third voltage (1200V).

[0049] Figure 22 It is a table summarizing the states of each mode of the energy storage system 1 in the second embodiment.

[0050] Explanation of reference numerals in the attached figures

[0051] 1. Energy storage system

[0052] 2 batteries

[0053] 3 Three-phase motor

[0054] 4 Auxiliary machines

[0055] 5 inverters

[0056] 10 Control Department

[0057] 11N power supply circuit (power transmission path on the negative side)

[0058] 11P power supply circuit (power transmission path on the positive side)

[0059] 12P Auxiliary Machine Drive Circuit

[0060] 13N DC power supply circuit (DC power supply circuit on the negative side)

[0061] 13-pin DC power supply circuit (DC power supply circuit on the positive side)

[0062] 14-branch circuit

[0063] 21 Battery Storage Unit

[0064] 31 neutral point

[0065] 32U, 32V, 32W coil

[0066] 34 Third connecting part

[0067] 41 First Switchgear Section (Switchgear Group)

[0068] 42 Second Switch Section (Third Changeover Switch)

[0069] 43 Third Switch Section (Fourth Changeover Switch)

[0070] 44 Fourth Switch Section (First Switch)

[0071] 45 Fifth Switch Section (Second Switch)

[0072] 111P First Connecting Part

[0073] 112P Second Connecting Part

[0074] 113P Fourth Connection Section Detailed Implementation

[0075] Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings. First, referring to... Figures 1 to 16 The first embodiment of the present invention will be described.

[0076] [First Implementation Method]

[0077] Figure 1The energy storage system 1 shown in the first embodiment is installed in electric vehicles such as electric cars. Electric vehicles equipped with the energy storage system 1 support charging devices with upper limits of 400V (500V), 800V (1000V), and 1200V (1500V). It can not only quickly charge the battery 2 with charging voltages of 400V, 800V, and 1200V, but also drive the three-phase motor 3 and auxiliary equipment 4 with a base voltage of 800V. Furthermore, the charging voltages of 400V, 800V, and 1200V are merely examples; the energy storage system 1 is not limited to these, as long as it can be charged by charging devices with different upper limit voltages.

[0078] Specifically, such as Figure 1 As shown, the energy storage system 1 includes a battery 2, a three-phase motor 3, an auxiliary unit 4, an inverter 5 (INV), a DC-DC converter 6, power supply circuits 11P and 11N, auxiliary unit drive circuits 12P and 12N, DC power supply circuits 13P and 13N, a branch circuit 14, and a control unit 10. Figure 1 In the figure, reference numeral 7 is the drive unit and reference numeral 8 is the auxiliary unit.

[0079] like Figure 1 and Figure 2 As shown, the battery 2 includes six energy storage units 21, a first switch unit 41, a main contactor M / C, a pre-charge contactor P / C, a first resistor R1, a current sensor IS, and a current circuit breaker FUSE.

[0080] The energy storage section 21 consists of battery modules capable of charging and discharging at 400V.

[0081] The main contactor M / C is located at the positive terminal of the battery 2 and functions as a main switch to connect and disconnect the battery 2 from the external power supply circuit 11P.

[0082] like Figure 2 As shown, the first switching unit 41 includes, for example, eight switches (S / C_A, S / C_B, S / C_C, S / C_D, S / C_E, S / C_F, S / C_G, S / C_H). These eight switches are an example of a switch group, switching the connection states of the six energy storage units 21 of the battery 2. When... Figure 4 With the six energy storage units 21 connected in parallel as shown, the battery 2 can be charged and discharged at 400V under the first voltage condition. Hereinafter, this first voltage condition that enables charging and discharging at 400V will also be referred to as the 400V start-up state.

[0083] In addition, Figure 5In the second voltage state shown, where the three energy storage units 21 connected in parallel in two groups are connected in series, the battery 2 can be charged and discharged at 800V. Hereinafter, this second voltage state, capable of charging and discharging at 800V, will also be referred to as the 800V start-up state. Furthermore, in Figure 6 In the third voltage state shown, where the two energy storage units 21 connected in parallel are connected in series, the battery 2 can be charged and discharged at 1200V. Hereinafter, this third voltage state, which enables charging and discharging at 1200V, will also be referred to as the 1200V start-up state.

[0084] return Figure 1 The pre-charge contactor P / C is connected in series with the first resistor R1 and in parallel with the main contactor M / C. When pre-charging the smoothing capacitor C1, the pre-charge contactor P / C closes before the main contactor M / C closes, thereby protecting the main contactor M / C from excessive inrush current. The pre-charge contactor P / C remains open except when pre-charging the smoothing capacitor C1.

[0085] The current sensor IS is positioned between the main contactor M / C and the six energy storage units 21 to measure the current.

[0086] A current circuit breaker (FUSE) is located at the negative terminal of the battery 2 and disconnects the battery 2 from the external power supply circuit (11N) in case of an abnormality. In the energy storage system 1 of this embodiment, the current circuit breaker (FUSE) is composed of a high-temperature fuse capable of actively cutting off the current based on an electrical signal. In case of an abnormality (such as a vehicle collision or a short circuit in the battery 2), the current circuit breaker (FUSE) disconnects the circuit and opens all contactors in the battery 2.

[0087] The three-phase motor 3 has three-phase coils 32U, 32V, and 32W connected at one end to the neutral point 31, and is driven to rotate by power supplied from the battery 2 via the inverter 5. In this embodiment, the three-phase motor 3 has a U-phase terminal 33U, a V-phase terminal 33V, and a W-phase terminal 33W connected to the other end of the coils 32U, 32V, and 32W. The U-phase terminal 33U, V-phase terminal 33V, and W-phase terminal 33W are connected to the inverter 5. Furthermore, the other end of any one phase coil 32U, 32V, or 32W is connected to a branch circuit 14 at a third connection portion 34. In this embodiment, the U-phase coil 32U of the three-phase coils 32U, 32V, and 32W is connected to the branch circuit 14 at the third connection portion 34 located between the U-phase terminal 33U and the inverter 5.

[0088] Inverter 5, through the switching of multiple switching elements, converts the DC power supplied from battery 2 into three-phase AC power to drive the three-phase motor 3 to rotate. For example... Figure 3As shown, the inverter 5 includes: a first branch circuit 51 comprising a first high-side switch TH1, a first low-side switch TL1, and a first node P1 connected in series with the first high-side switch TH1 and the first low-side switch TL1; a second branch circuit 52 comprising a second high-side switch TH2, a second low-side switch TL2, and a second node P2 connected in series with the second high-side switch TH2 and the second low-side switch TL2; and a third branch circuit 53 comprising a third high-side switch TH3, a third low-side switch TL3, and a third node P3 connected in series with the third high-side switch TH3 and the third low-side switch TL3. The high-side switch ends of the first branch circuit 51, the second branch circuit 52, and the third branch circuit 53 are connected in parallel with the positive-side power supply circuit 11P, and the low-side switch ends are connected in parallel with the negative-side power supply circuit 11N.

[0089] Furthermore, the first node P1 is connected to the coil 32U via the U-phase terminal 33U, the second node P2 is connected to the coil 32V via the V-phase terminal 33V, and the third node P3 is connected to the coil 32W via the W-phase terminal 33W. Switches TH1, TL1, TH2, TL2, TH3, and TL3 are semiconductor switches, such as those composed of MOSFETs, and their on / off control is achieved by adjusting the gate voltage through the control unit 10.

[0090] The diodes acting as return diodes are connected in parallel with each of the switches TH1, TL1, TH2, TL2, TH3, and TL3. These return diodes are designed to allow the current flowing backward from the three-phase motor 3 side to the battery 2 side when switches TH1, TL1, TH2, TL2, TH3, and TL3 are opened, thus preventing damage to the switching elements. In other words, the inverter 5 allows current to flow from the three-phase motor 3 side to the battery 2 side regardless of whether the gate is on or off; it only allows current to flow from the battery 2 side to the three-phase motor 3 side when the gate is on.

[0091] As will be described in detail later, when charging at 400V, the energy storage system 1 supplies 400V from the branch circuit 14 to the third connection 34. By switching switches TH1, TL1, TH2, TL2, TH3, and TL3, the three-phase motor 3 can function as part of the boost circuit. When charging at 1200V, the power supply circuit 11P supplies 1200V to the inverter 5. By switching switches TH1, TL1, TH2, TL2, TH3, and TL3, the three-phase motor 3 can function as part of the buck circuit.

[0092] Auxiliary unit 4 is a high-voltage driven vehicle device capable of being driven by DC power from battery 2 and an external power source, such as an electric compressor for air conditioning, a heater, etc. Auxiliary unit 4 is connected to battery 2 via auxiliary unit drive circuits 12P and 12N and power supply circuits 11P and 11N (described later). Furthermore, auxiliary unit 4 is configured to be connected to an external power source via auxiliary unit drive circuits 12P and 12N, power supply circuits 11P and 11N, and DC power supply circuits 13P and 13N (described later). Additionally, auxiliary unit 4 is configured to be connected to three-phase motor 3 via connection path 15 and branch circuit 14 (described later). In this embodiment, auxiliary unit 4 operates at a base voltage of 800V.

[0093] DC-DC converter 6 is connected in parallel with auxiliary machine 4 in auxiliary machine drive circuit 12P to step down the DC power from battery 2 and external power supply to drive low-voltage drive vehicle equipment.

[0094] Power supply circuits 11P and 11N consist of a positive and negative pair, connecting the battery 2 to the inverter 5 (three-phase motor 3). Power supply circuits 11P and 11N have first connection portions 111P and 111N serving as connections to DC power supply circuits 13P and 13N. Further from the first connection portions 111P and 111N on the inverter 5 side, there are second connection portions 112P and 112N serving as connections to auxiliary drive circuits 12P and 12N. Additionally, the positive-side power supply circuit 11P has a third switch portion 43 that connects and disconnects the circuit between the second connection portion 112P (connecting to the auxiliary drive circuit 12P) and the first connection portion 111P (connecting to the DC power supply circuit 13P). The third switch portion 43 is composed of a contactor VS / C_A. The contactor VS / C_A is, for example, an electromagnetic contactor. Therefore, when the third switch section 43 (contactor VS / C_A) is in the ON state, power transmission between the first connection section 111P and the second connection section 112P is allowed, and when the third switch section 43 (contactor VS / C_A) is in the OFF state, power transmission between the first connection section 111P and the second connection section 112P is cut off.

[0095] Additionally, a first voltage sensor V_PIN, a smoothing capacitor C1, and a second resistor R2 are provided on the inverter 5 side of the power supply circuits 11P and 11N. The first voltage sensor V_PIN, the smoothing capacitor C1, and the second resistor R2 are provided on the circuit connecting the positive-side power supply circuit 11P and the negative-side power supply circuit 11N. Furthermore, the second resistor R2 is provided to discharge the smoothing capacitor C1 when the circuit is disconnected.

[0096] The DC power supply circuits 13P and 13N consist of a positive and negative pair. One end of each circuit has a charging terminal 131P or 131N for connecting to an external power source, such as a charging device. The other end is connected to the power supply circuits 11P and 11N via first connecting portions 111P and 111N. Contactors QC / C_A and QC / C_B are provided on the DC power supply circuits 13P and 13N to switch the circuits on and off. Contactors QC / C_A and QC / C_B are, for example, electromagnetic contactors. When contactors QC / C_A and QC / C_B are in the ON state, power supply from an external power source to the power supply circuits 11P and 11N is allowed; when contactors QC / C_A and QC / C_B are in the OFF state, power supply from an external power source to the power supply circuits 11P and 11N is cut off.

[0097] Furthermore, in the DC power supply circuits 13P and 13N, a second voltage sensor V_BAT is provided at a position closer to the first connection portion 111P and 111N than contactors QC / C_A and QC / C_B. Additionally, a third voltage sensor V_QC is provided at a position closer to the charging terminals 131P and 131N than contactors QC / C_A and QC / C_B.

[0098] The auxiliary drive circuits 12P and 12N consist of a positive and negative pair. One end is connected in parallel with the auxiliary machine 4 and the DC-DC converter 6, and the other end is connected to the power supply circuits 11P and 11N via the second connection parts 112P and 112N. A fifth switch part 45 is provided on the positive side of the auxiliary drive circuit 12P to turn the circuit on and off. The fifth switch part 45 is composed of a contactor VS / C_B. The contactor VS / C_B is, for example, an electromagnetic contactor. Therefore, when the contactor VS / C_B is in the on state, power is supplied from the DC power supply circuit 13P on the positive side to the auxiliary machine 4 and the DC-DC converter 6. On the other hand, when the contactor VS / C_B is in the off state, the power supply from the DC power supply circuit 13P on the positive side to the auxiliary machine 4 and the DC-DC converter 6 is cut off.

[0099] Branch circuit 14 branches off in the DC power supply circuit 13P on the positive side, closer to the first connection portion 111P than the contactor QC / C_A and the second voltage sensor V_BAT, and connects to any one of the coils of the three-phase motor 3 via the third connection portion 34. Branch circuit 14 is provided with a second switch portion 42 for turning the circuit on and off, and a connecting path 15 that branches off from a fifth connection portion 35 located closer to the third connection portion 34 than the second switch portion 42 and connects to the auxiliary drive circuit 12P.

[0100] The second switching section 42 is composed of a contactor QC / C_C. The contactor QC / C_C is, for example, an electromagnetic contactor. Therefore, when the second switching section 42 (contactor QC / C_C) is in the ON state, power transmission between the DC power supply circuit 13P on the positive side and the branch circuit 14 is allowed; when the second switching section 42 (contactor QC / C_C) is in the OFF state, power transmission between the DC power supply circuit 13P on the positive side and the branch circuit 14 is cut off.

[0101] The connecting flow path 15 is connected to the auxiliary drive circuit 12P on the positive side via the fourth connection portion 113P. A fourth switch portion 44 is provided in the connecting flow path 15 to turn the circuit on and off. The fourth switch portion 44 is composed of a contactor QC / C_D. The contactor QC / C_D is, for example, an electromagnetic contactor. Therefore, when the fourth switch portion 44 (contactor QC / C_D) is in the on state, power is supplied from the branch circuit 14 to the auxiliary drive circuit 12P; when the fourth switch portion 44 (contactor QC / C_D) is in the off state, the power supply from the branch circuit 14 to the auxiliary drive circuit 12P is cut off.

[0102] Additionally, between the fourth switch section (contactor QC / C_D) and the fourth connection section 113P, the connecting flow path 15 is connected to the other end of a smooth capacitor C2, which has one end connected to the power supply circuit 11N on the negative side.

[0103] The control unit 10, for example, is a vehicle ECU, which controls the driving and charging of the energy storage system 1. More specifically, the control unit 10 performs the on / off control of the first to fifth switching units 41 to 45, the on / off control of each contactor (including PWM control), the control of the DC-DC converter 6, and the control of the inverter 5.

[0104] Next, refer to Figures 7 to 14 The operation of the energy storage system 1 will be explained.

[0105] Figure 7 This is a diagram showing the flow of current when an electric vehicle equipped with the energy storage system 1 of the first embodiment is in operation (800V operation).

[0106] As described above, the electric vehicle equipped with the energy storage system 1 drives the three-phase motor 3 and auxiliary motor 4 with a base voltage of 800V, and the battery 2 is controlled to operate at a voltage of 800V during operation. Figure 5 The circuit is shown in the 800V start-up state. Additionally, the control unit 10 connects the main contactor M / C, the third switch unit 43 (contactor VS / C_A), and the fifth switch unit 45 (contactor VS / C_B), while disconnecting contactors QC / C_A, QC / C_B, the second switch unit 42 (contactor QC / C_C), and the fourth switch unit 44 (contactor QC / C_D). This circuit mode is referred to as the first mode.

[0107] In this first mode, 800V is supplied from the battery 2 to the three-phase motor 3 via the inverter 5, thus enabling the electric vehicle to run. At this time, the auxiliary motor 4 is driven by the 800V voltage supplied from the battery 2 via the power supply circuits 11P and 11N and the auxiliary motor drive circuits 12P and 12N.

[0108] Figure 8 This is a diagram showing the flow of current when the electric vehicle equipped with the energy storage system 1 of the first embodiment is charged at the first voltage (400V charging).

[0109] When charging using a 400V charging device, battery 2 is controlled to... Figure 4 The circuit is shown in the 400V startup state. Additionally, the control unit 10 connects the main contactor M / C, contactor QC / C_A, contactor QC / C_B, the second switch unit 42 (contactor QC / C_C), and the fifth switch unit 45 (contactor VS / C_B), while disconnecting the third switch unit 43 (contactor VS / C_A) and the fourth switch unit 44 (contactor QC / C_D). This circuit mode is referred to as the fourth mode. As a result, a 400V voltage is supplied to the battery 2 from the charging terminals 131P and 131N via the DC power supply circuit 13P and the power supply circuit 11P, and a 400V voltage is supplied to the coil 32U via the DC power supply circuit 13P and the branch circuit 14.

[0110] Here, in order to drive the auxiliary machine 4, which has a base voltage of 800V, it is necessary to boost the 400V voltage to the base voltage of the auxiliary machine 4, i.e., 800V. Therefore, the control unit 10 performs high-frequency switching on the second low-side switch TL2 and the third low-side switch TL3, performing the following... Figure 9 The on / off states of the second low-side switch TL2 and the third low-side switch TL3 shown are as follows: Figure 10 The boost operation switches between the open states of the second low-side switch TL2 and the third low-side switch TL3 shown. Furthermore, the other switches TL1, TH1 to TH3 of the inverter 5 remain in the open state.

[0111] Therefore, in Figure 9 When the second low-side switch TL2 and the third low-side switch TL3 are in the ON state, the energy stored in coils 32U, 32V, and 32W is... Figure 10 When the second low-side switch TL2 and the third low-side switch TL3 shown are in the open state, they are released, thereby boosting the 400V voltage supplied from the charging terminals 131P and 131N to 800V and supplying it to the auxiliary machine 4 from the inverter 5 via the power supply circuit 11P and the auxiliary machine drive circuit 12P.

[0112] Figure 11This is a diagram showing the flow of current when the electric vehicle equipped with the energy storage system 1 of the first embodiment is charged at the second voltage (800V charging).

[0113] When charging using an 800V charging device, battery 2 is controlled to... Figure 5 The circuit is shown in the 800V startup state. Additionally, the control unit 10 connects the main contactor M / C, contactor QC / C_A, contactor QC / C_B, the third switch unit 43 (contactor VS / C_A), and the fifth switch unit 45 (contactor VS / C_B), while disconnecting the second switch unit 42 (contactor QC / C_C) and the fourth switch unit 44 (contactor QC / C_D). This circuit mode is referred to as the third mode. As a result, 800V is supplied to the battery 2 from the charging terminals 131P and 131N via the DC power supply circuit 13P and the power supply circuit 11P, and 800V is supplied to the auxiliary machine 4 via the DC power supply circuit 13P, the power supply circuit 11P, and the auxiliary machine drive circuit 12P.

[0114] Figure 12 This is a diagram showing the flow of current when the electric vehicle equipped with the energy storage system 1 of the first embodiment is charged with the third voltage (1200V charging).

[0115] When charging using a 1200V charging device, battery 2 is controlled to... Figure 6 The circuit is shown in the 1200V startup state. Additionally, the control unit 10 connects the main contactor M / C, contactor QC / C_A, contactor QC / C_B, the third switch unit 43 (contactor VS / C_A), and the fourth switch unit 44 (contactor QC / C_D), while disconnecting the second switch unit 42 (contactor QC / C_C) and the fifth switch unit 45 (contactor VS / C_B). This circuit mode is referred to as the second mode. As a result, a 1200V voltage is supplied to the battery 2 from the charging terminals 131P and 131N via the DC power supply circuit 13P and the power supply circuit 11P, and a 1200V voltage is also supplied to the inverter 5 via the DC power supply circuit 13P and the power supply circuit 11P.

[0116] Here, in order to drive the auxiliary machine 4, which has a base voltage of 800V, it is necessary to step down the 1200V voltage to the base voltage of the auxiliary machine 4, i.e., 800V. Therefore, the control unit 10 performs high-frequency switching on the second high-side switch TH2 and the third high-side switch TH3, performing the following... Figure 13 The on / off states of the second high-side switch TH2 and the third high-side switch TH3 shown are as follows: Figure 14 The step-down operation switches between the open states of the second high-side switch TH2 and the third high-side switch TH3 shown. Furthermore, the other switches TH1, TL1 to TL3 of the inverter 5 remain in the open state.

[0117] Therefore, in Figure 13 The energy stored in coils 32U, 32V, and 32W when the second high-side switch TH2 and the third high-side switch TH3 are in the ON state, Figure 14 The second high-side switch TH2 and the third high-side switch TH3 shown are released in the open state, so that the 1200V voltage supplied from the charging terminals 131P and 131N is reduced to 800V, and supplied from the three-phase motor 3 to the auxiliary machine 4 via the branch circuit 14, the connecting current path 15 and the auxiliary machine drive circuit 12P.

[0118] Figure 15 It is a table that summarizes the states of switches and contactors in each mode of the energy storage system 1 of the first embodiment.

[0119] Figure 16 This is a flowchart representing the control process of the energy storage system 1.

[0120] First, it is determined whether the electric vehicle equipped with the energy storage system 1 is in driving mode or charging mode (step S1). In driving mode, for example, the power switch is pressed while the user is pressing the brake pedal of the electric vehicle. If driving mode is detected in step S1, the circuit mode of the energy storage system 1 is set to the first mode described above (step S2).

[0121] On the other hand, when the charging mode is active in step S1, the control unit 10 starts communication with the charging device (step S4) and obtains the charger specifications of the charging device when it detects that the charging plug is inserted into the charging terminals 131P and 131N (step S3). In step S5, if the upper limit voltage of the charger is 1500V, the circuit mode of the energy storage system 1 is set to the second mode described above (step S6); if the upper limit voltage is 1000V, the circuit mode of the energy storage system 1 is set to the third mode described above (step S7); and if the upper limit voltage is 500V, the circuit mode of the energy storage system 1 is set to the fourth mode described above (step S8).

[0122] If the mode setting of the energy storage system 1 is completed, charging begins (step S9). If charging ends (step S10), the switch and contactor of the energy storage system 1 are all disconnected to end the process (step S11).

[0123] Thus, according to the energy storage system 1 of the first embodiment, regardless of whether the external charging device is a system charging with a first voltage (400V charging), a system charging with a second voltage (800V charging), or a system charging with a third voltage (1200V charging), by using the first switching unit 41 (S / C_A, S / C_B, S / C_C, S / C_D, S / C_E, S / C_F, S / C_G, S / C_H) to switch the connection mode of the multiple energy storage units 21, charging can be performed appropriately according to the voltage state of the charging device. That is, charging can be performed without a voltage converter, thus avoiding the efficiency degradation caused by the voltage converter, and eliminating the need for a voltage converter for charging.

[0124] Furthermore, since the DC power supply circuit 13P, which is connected to the positive terminal of the inverter 5 and the battery 2 via the first connection 111P, has a branch circuit 14 connected to the coil of any one phase of the three-phase motor 3, voltage conversion can be performed using the three-phase motor 3 and the inverter 5. In particular, by providing a fourth switch section 44 (contactor QC / C_D) and a fifth switch section 45 (contactor VS / C_B), voltage boosting and bucking can be performed using the coil of the three-phase motor 3 even when the voltage state of the charging device and the operating voltage of the auxiliary machine 4 are different. As a result, a dedicated voltage converter is not required, and manufacturing costs can be reduced.

[0125] [Second Implementation]

[0126] Next, refer to Figures 17 to 22 The energy storage system 1 of the second embodiment will be described. Here, for structures common to the first embodiment, the description of the first embodiment is sometimes referred to by using the same reference numerals as the first embodiment.

[0127] In the energy storage system 1 of the first embodiment described above, when observing the contactor QC / C_A, which serves as the main switch for charging, and the main contactor M / C, which serves as the main switch for the battery 2, with reference to the battery 2, the contactor QC / C_A is connected in series with respect to the main contactor M / C. However, in the energy storage system 1 of the second embodiment, as... Figure 17 As shown, contactor QC / C_A is connected in parallel with main contactor M / C.

[0128] In the energy storage system 1 of the second embodiment, during charging at a first voltage (400V) or a third voltage (1200V), the first voltage (400V) or the third voltage (1200V), which serves as the charging voltage for the battery 2, can be separated from the second voltage (800V) boosted by the three-phase motor 3 and the inverter 5 via the main contactor M / C. Therefore, the contactor VS / C_A of the first embodiment is not provided. Furthermore, in the energy storage system 1 of the second embodiment, contactors QC / C_A, QC / C_B, the second switch unit 42 (contactor QC / C_C), the second voltage sensor V_BAT, and the third voltage sensor V_QC are disposed within the battery 2.

[0129] In the second embodiment, the eight switches (S / C_A, S / C_B, S / C_C, S / C_D, S / C_E, S / C_F, S / C_G, S / C_H) are an example of the first switch section 41, the contactor QC / C_C is an example of the second switch section 42, the contactor QC / C_D is an example of the fourth switch section 44, and the contactor VS / C_B is an example of the fifth switch section 45, which is the same as the first embodiment. However, the main contactor M / C is an example of the third switch section 43, which is different from the first embodiment.

[0130] Reference Figures 18 to 21 The operation of the energy storage system 1 in the second embodiment will be described.

[0131] Figure 18 This is a diagram showing the flow of current when an electric vehicle equipped with the energy storage system 1 of the second embodiment is in operation (800V operation).

[0132] As described above, the electric vehicle equipped with the energy storage system 1 drives the three-phase motor 3 and auxiliary motor 4 with a base voltage of 800V, and the battery 2 is controlled to operate at a voltage of 800V during operation. Figure 5 The circuit is shown in the 800V start-up state. Additionally, the control unit 10 connects the third switch unit 43 (main contactor M / C) and the fifth switch unit 45 (contactor VS / C_B), while disconnecting contactors QC / C_A, QC / C_B, the second switch unit 42 (contactor QC / C_C), and the fourth switch unit 44 (contactor QC / C_D). This circuit mode is referred to as the eleventh mode.

[0133] In this eleventh mode, 800V is supplied from the battery 2 to the three-phase motor 3 via the inverter 5, thus enabling the electric vehicle to run. At this time, the auxiliary motor 4 is driven by the 800V voltage supplied from the battery 2 via the power supply circuits 11P and 11N and the auxiliary motor drive circuits 12P and 12N.

[0134] Figure 19This is a diagram showing the flow of current when the electric vehicle equipped with the energy storage system 1 of the second embodiment is charged at the first voltage (400V charging).

[0135] When charging using a 400V charging device, battery 2 is controlled to... Figure 4 The circuit is shown in the 400V startup state. Additionally, the control unit 10 connects contactors QC / C_A, QC / C_B, the second switch unit 42 (contactor QC / C_C), and the fifth switch unit 45 (contactor VS / C_B), while disconnecting the third switch unit 43 (main contactor M / C) and the fourth switch unit 44 (contactor QC / C_D). This circuit mode is referred to as the fourteenth mode. As a result, a 400V voltage is supplied to the battery 2 from the charging terminals 131P and 131N via the DC power supply circuit 13P and the power supply circuit 11P, and a 400V voltage is supplied to the coil 32U via the DC power supply circuit 13P and the branch circuit 14.

[0136] Here, in order to drive auxiliary machine 4, which has a base voltage of 800V, it is necessary to boost the 400V voltage to the base voltage of auxiliary machine 4, i.e., 800V. Regarding the boosting operation, refer to the first embodiment. Figure 9 and Figure 10 As explained, detailed descriptions are omitted. Through a boost operation, the 400V voltage supplied from the charging terminals 131P and 131N is boosted to 800V and supplied from the inverter 5 to the auxiliary machine 4 via the power supply circuit 11P and the auxiliary machine drive circuit 12P.

[0137] Figure 20 This is a diagram showing the current flow during second-voltage charging (800V charging) of an electric vehicle equipped with the energy storage system 1 of the second embodiment.

[0138] When charging using an 800V charging device, battery 2 is controlled to... Figure 5 The circuit is shown in the 800V startup state. Additionally, the control unit 10 connects the third switch unit 43 (main contactor M / C), contactor QC / C_A, contactor QC / C_B, and the fifth switch unit 45 (contactor VS / C_B), while disconnecting the second switch unit 42 (contactor QC / C_C) and the fourth switch unit 44 (contactor QC / C_D). This circuit mode is referred to as the thirteenth mode. As a result, 800V is supplied to the battery 2 from the charging terminals 131P and 131N via the DC power supply circuit 13P and the power supply circuit 11P, and 800V is supplied to the auxiliary machine 4 via the DC power supply circuit 13P, the power supply circuit 11P, and the auxiliary machine drive circuit 12P.

[0139] Figure 21This is a diagram showing the flow of current when the electric vehicle equipped with the energy storage system 1 of the second embodiment is charged with the third voltage (1200V charging).

[0140] When charging using a 1200V charging device, battery 2 is controlled to... Figure 6 The circuit is shown in the 1200V startup state. Additionally, the control unit 10 connects contactors QC / C_A, QC / C_B, the third switch unit 43 (main contactor M / C), and the fourth switch unit 44 (contactor QC / C_D), while disconnecting the second switch unit 42 (contactor QC / C_C) and the fifth switch unit 45 (contactor VS / C_B). This circuit mode is referred to as the twelfth mode. As a result, a 1200V voltage is supplied to the battery 2 from the charging terminals 131P and 131N via the DC power supply circuit 13P and the power supply circuit 11P, and a 1200V voltage is also supplied to the inverter 5 via the DC power supply circuit 13P and the power supply circuit 11P.

[0141] Here, in order to drive auxiliary machine 4, which has a base voltage of 800V, it is necessary to step down the 1200V voltage to the base voltage of auxiliary machine 4, i.e., 800V. Regarding the voltage reduction operation, refer to the first embodiment. Figure 13 and Figure 14 As explained, detailed descriptions are omitted. Through a step-down operation, the 1200V voltage supplied from the charging terminals 131P and 131N is reduced to 800V and supplied from the three-phase motor 3 to the auxiliary machine 4 via the branch circuit 14, the connecting current path 15, and the auxiliary machine drive circuit 12P.

[0142] Figure 22 This is a table summarizing the states of switches and contactors in each mode of the energy storage system 1 of the second embodiment.

[0143] Thus, in the energy storage system 1 of the second embodiment, similarly to the first embodiment, regardless of whether the external charging device is a system charging at a first voltage (400V charging), a system charging at a second voltage (800V charging), or a system charging at a third voltage (1200V charging), by using the first switching unit 41 (S / C_A, S / C_B, S / C_C, S / C_D, S / C_E, S / C_F, S / C_G, S / C_H) to switch the connection mode of the multiple energy storage units 21, charging can be performed appropriately according to the voltage state of the charging device. That is, charging can be performed without a voltage converter, thus avoiding the efficiency degradation caused by the voltage converter, and eliminating the need for a voltage converter for charging.

[0144] Furthermore, since the DC power supply circuit 13P, which is connected to the positive terminal of the inverter 5 and the battery 2 via the first connection 111P, has a branch circuit 14 connected to the coil of any one phase of the three-phase motor 3, voltage conversion can be performed using the three-phase motor 3 and the inverter 5. In particular, by providing a fourth switch section 44 (contactor QC / C_D) and a fifth switch section 45 (contactor VS / C_B), voltage boosting and bucking can be performed using the coil of the three-phase motor 3 even when the voltage state of the charging device and the operating voltage of the auxiliary machine 4 are different. As a result, a dedicated voltage converter is not required, and manufacturing costs can be reduced.

[0145] Various embodiments have been described above with reference to the accompanying drawings, but the present invention is not limited to these examples. It is obvious that those skilled in the art will conceive of various modifications or alterations within the scope of the claims, and it should be understood that these modifications and alterations also fall within the technical scope of the present invention. Furthermore, the constituent elements of the above embodiments can be combined arbitrarily without departing from the spirit of the invention.

[0146] For example, in the above embodiment, it is described that the control unit 10 communicates with the charging device, and the communication method can be any communication method such as CAN communication.

[0147] At least the following items are described in this specification. Furthermore, although the corresponding components and the like are shown in parentheses in the above embodiments, the present invention is not limited thereto.

[0148] (1) An energy storage system (energy storage system 1), comprising:

[0149] The battery (battery 2) includes multiple energy storage units (energy storage units 21) and a switch group (first switch group 41). The switch group can switch between a first voltage state that can be charged at a first voltage (400V), a second voltage state that can be charged at a second voltage (800V) that is higher than the first voltage, and a third voltage state that can be charged at a third voltage (1200V) that is higher than the second voltage by switching the connection state of the multiple energy storage units.

[0150] A three-phase motor (three-phase motor 3) has three-phase coils (coils 32U, 32V, 32W) connected at a neutral point (neutral point 31) and is driven by power supplied from the battery.

[0151] An inverter (inverter 5) is connected to the power transmission path (power supply circuits 11P and 11N) between the battery and the three-phase motor.

[0152] A DC power supply circuit (DC power supply circuit 13P, 13N) is connected to a first connection part (first connection part 111P, 111N) located on the power transmission path between the inverter and the battery.

[0153] Auxiliary machine (auxiliary machine 4), which is capable of being driven using DC power from the battery and an external power source; and

[0154] An auxiliary machine drive circuit (auxiliary machine drive circuit 12P) is connected to a second connection (second connection 112P) located on the power transmission path between the inverter and the first connection, and supplies power to the auxiliary machine.

[0155] The DC power supply circuit on the positive side has a branch circuit (branch circuit 14) that is connected to the coil of any one phase of the three-phase coil at the third connection part (third connection part 34).

[0156] The branch circuit is connected to the auxiliary machine drive circuit via the first switching switch (fourth switching part 44) at the fourth connecting part (fourth connecting part 113P).

[0157] In the auxiliary machine drive circuit, a second switching switch (fifth switching part 45) is provided between the second connecting part (second connecting part 112P) and the fourth connecting part (fourth connecting part 113P).

[0158] According to (1), regardless of whether the external charging device is a system that charges at a first voltage, a system that charges at a second voltage, or a system that charges at a third voltage, by switching the connection mode of multiple energy storage units using a switch group, charging can be performed appropriately according to the voltage state of the charging device. That is, charging can be performed without a voltage converter, thus avoiding the efficiency degradation caused by the voltage converter, and eliminating the need for a voltage converter for charging.

[0159] Furthermore, since the DC power supply circuit on the positive side, connected to the first connection point on the power transmission path between the inverter and the battery, has a branch circuit connected to the coil of any one phase of the three-phase motor, voltage conversion can be performed using the three-phase motor and the inverter. In particular, by providing a first switching switch and a second switching switch, voltage boosting and bucking can be performed using the coils of the three-phase motor even when the voltage state of the charging equipment and the operating voltage of the auxiliary equipment differ. Therefore, a dedicated voltage converter is not required, thus reducing manufacturing costs.

[0160] (2) According to the energy storage system described in (1), wherein,

[0161] The auxiliary machine operates using the second voltage.

[0162] According to (2), in the case of charging with the second voltage and driving the three-phase motor with the second voltage, voltage conversion is not required. Whether charging with the first voltage or the third voltage, the auxiliary machine can be driven with the second voltage, thus reducing the amount of voltage conversion during boost and buck cycles. As a result, the scaling up of the system can be suppressed.

[0163] (3) The energy storage system according to (2) also has:

[0164] The control unit (control unit 10) controls the switch group, the first switching switch, the second switching switch, and the inverter.

[0165] When the control unit charges the battery with the first voltage, it sets the first switching switch to the off state and the second switching switch to the on state to control the inverter, thereby boosting the first voltage to generate the second voltage.

[0166] When the control unit charges the battery with the third voltage, it sets the first switching switch to the connected state and the second switching switch to the disconnected state to control the inverter, thereby reducing the third voltage to generate the second voltage.

[0167] According to (3), by controlling the inverter, it is possible to both boost and buck the voltage, thus eliminating the need for other semiconductor switches and reducing manufacturing costs.

[0168] (4) According to the energy storage system described in (3), wherein,

[0169] A third switching switch (second switching part 42) is provided in the branch circuit to cut off the power transmission between the DC power supply circuit on the positive side and the branch circuit.

[0170] A fourth switching switch (third switching part 43) is provided between the first connection part (first connection part 111P) and the second connection part (second connection part 112P) in the power transmission path between the inverter and the battery.

[0171] When the control unit charges the battery with the first voltage, it connects the third switch and disconnects the fourth switch.

[0172] When the battery is charged with the third voltage, the third switching switch is turned off and the fourth switching switch is turned on.

[0173] According to (4), when charging with a first voltage or a third voltage, the part that becomes the first voltage state or the third voltage state can be separated from the part that becomes the second voltage state by the third switching switch and the fourth switching switch.

[0174] (5) The energy storage system according to (4), wherein,

[0175] When the battery is charged with the second voltage and the three-phase motor is driven with the second voltage, the control unit sets the first switch and the third switch to the off state, and sets the second switch and the fourth switch to the connected state.

[0176] According to (5), it is possible to drive the auxiliary machine with the second voltage while charging the battery or driving the three-phase motor with the second voltage without supplying power to the branch circuit.

[0177] (6) The energy storage system according to (1), wherein,

[0178] One end of the first switching switch is connected to the branch circuit, and the other end of the first switching switch is connected to the negative side (power supply circuit 11N) of the power transmission path of the battery and the three-phase motor via a capacitor.

[0179] According to (6), the power supplied to the auxiliary machine can be smoothed.

Claims

1. An energy storage system, comprising: A storage battery includes a switch assembly and multiple energy storage units. The switch assembly can switch between a first voltage state that can be charged with a first voltage, a second voltage state that can be charged with a second voltage that is higher than the first voltage, and a third voltage state that can be charged with a third voltage that is higher than the second voltage by switching the connection state of the multiple energy storage units. A three-phase motor having three-phase coils connected at a neutral point, driven by power supplied from the battery; An inverter is connected to the power transmission path between the battery and the three-phase motor; A DC power supply circuit is connected to a first connection point located on the power transmission path between the inverter and the battery; Auxiliary equipment, which is capable of being driven using DC power from the battery and an external power source; as well as An auxiliary machine drive circuit, which is connected to a second connection point located on the power transmission path between the inverter and the first connection point, supplies power to the auxiliary machine. The DC power supply circuit on the positive side has a branch circuit that is connected to the coil of any one of the three phases of the coil at the third connection point. The branch circuit is connected to the auxiliary machine drive circuit at the fourth connection point via a first switching switch. In the auxiliary machine drive circuit, a second switching switch is provided between the second connection part and the fourth connection part.

2. The energy storage system according to claim 1, wherein, The auxiliary machine operates using the second voltage.

3. The energy storage system according to claim 2 further comprises: The control unit controls the switch group, the first switching switch, the second switching switch, and the inverter. When the control unit charges the battery with the first voltage, it sets the first switching switch to the off state and the second switching switch to the on state to control the inverter, thereby boosting the first voltage to generate the second voltage. When the control unit charges the battery with the third voltage, it sets the first switching switch to the connected state and the second switching switch to the disconnected state to control the inverter, thereby reducing the third voltage to generate the second voltage.

4. The energy storage system according to claim 3, wherein, The branch circuit is equipped with a third switching switch that cuts off the power transfer between the DC power supply circuit on the positive side and the branch circuit. A fourth switching switch is provided between the first connection portion and the second connection portion on the power transmission path between the inverter and the battery. When the control unit charges the battery with the first voltage, it connects the third switch and disconnects the fourth switch. When the battery is charged with the third voltage, the third switching switch is turned off and the fourth switching switch is turned on.

5. The energy storage system according to claim 4, wherein, When the battery is charged with the second voltage and the three-phase motor is driven with the second voltage, the control unit sets the first switch and the third switch to the off state, and sets the second switch and the fourth switch to the connected state.

6. The energy storage system according to claim 1, wherein, One end of the first switching switch is connected to the branch circuit, and the other end of the first switching switch is connected to the negative side of the power transmission path of the battery and the three-phase motor via a capacitor.

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