WO2022269824A1

WO2022269824A1 - Battery module and motor system

Info

Publication number: WO2022269824A1
Application number: PCT/JP2021/023848
Authority: WO
Inventors: 和征榊原
Original assignee: 株式会社EViP
Priority date: 2021-06-23
Filing date: 2021-06-23
Publication date: 2022-12-29

Abstract

[Problem] To make it possible to efficiently control electrical discharging. [Solution] A battery module comprising: battery cell groups; a switching circuit that switches the battery cell groups to any one of a first state in which the battery cell groups are connected in series, a second state in which the battery cell groups are connected in parallel, and a third state in which all conduction paths between the battery cell groups are cut off; and an acceleration sensor, wherein a switch is made to any one of the first to third states in accordance with the rate of change of acceleration detected by the acceleration sensor.

Description

Battery module and motor system

The present invention relates to battery modules and motor systems.

In recent years, in consideration of the global environment, vehicles driven by internal combustion engines are being replaced by electric vehicles driven by motors or hybrid vehicles driven by both engines and motors. Three-phase motors are used in electric vehicles and hybrid vehicles, and Patent Literature 1 discloses a technique for suppressing voltage fluctuations in power lines to the three-phase motors.

JP 2019-140824 A

In conventional motor systems, the discharge current input from the battery power supply to the boost converter tends to be very large.

The present invention has been made in view of this background, and aims to provide a technique that can efficiently control discharge.

The main invention of the present invention for solving the above problems is a battery module comprising a battery cell group, a first state in which the battery cell group is connected in series, a second state in which the battery cell group is connected in parallel, or , and a third state in which all conduction paths between the battery cell groups are cut off; The state changes to any one of the first state to the third state.

Other problems disclosed by the present application and their solutions will be clarified in the section of the embodiment of the invention and the drawings.

According to the present invention, discharge can be efficiently controlled.

2 is a circuit block diagram showing an outline of the configuration of a battery module 2 according to this embodiment; FIG. 1 is a circuit block diagram showing an outline of the configuration of a motor system 101 according to this embodiment; FIG. FIG. 3 is a circuit block diagram showing an outline of state a in the configuration of the battery module 3 according to this embodiment. 3 is a circuit block diagram showing an outline of state b in the configuration of the battery module 3 according to this embodiment. FIG. 3 is a circuit block diagram showing an outline of state c in the configuration of the battery module 3 according to this embodiment. FIG. 1 is a circuit block diagram showing an outline of the configuration of a motor system 106 according to this embodiment; FIG. 4 is a flow chart diagram showing an outline of control of the main controller 9 of the motor system 106 according to this embodiment. FIG. 4 is a time chart diagram showing the waveform of the output voltage of one inverter 6 in the motor system 106 according to this embodiment and the waveform of the input voltage from the battery module 3 to the inverter 6. FIG.

As shown in FIG. 1, the battery module 2 includes a high-voltage-rated lithium-ion secondary battery cell group 1H formed by connecting a plurality of lithium-ion secondary battery cells in series. It is connected to a terminal 5 via an FET 4 as an element. The module controller 3 detects the voltage of the lithium ion secondary battery cell group 1H or the current of the lithium ion secondary battery cell group 1H, that is, the voltage appearing across the shunt resistor 6, and turns the FET 4 on or off. to control the output or stop of the discharge output from the terminal 5.

The motor system 101, as shown in FIG. 2, transmits the DC voltage output by the battery module 2U, the battery module 2V, and the battery module 2W, which have the same configuration as the battery module 2, through the high voltage power line 5U and the high voltage power line 5U. 5V and applied to the inverter 6U, the inverter 6V, and the inverter 6W via the high voltage power line 5W, respectively. The inverter 6U, the inverter 6V, and the inverter 6W input high-voltage DC voltage from the battery module 2U, the battery module 2V, and the battery module 2W, respectively, convert it to AC voltage, and shift the phase to a desired electrical angle. Three single-phase AC voltages are applied to the

magnetic pole coils

7U, 7V, and 7W, which are arranged in three phases in the motor, respectively, to generate a rotating magnetic field between the magnetic pole coils, thereby rotating the rotor. Control. The insulated communication lines 8a, 8b, and 8g transmit and receive insulated signals between the inverters arranged in independent closed circuits to synchronize the three single-phase alternating currents output from the three inverters. It is used to synchronize the voltage phase and shift it to the desired electrical angle.

One state of the battery module 3, state a, in which the battery module 3(a), as shown in FIG. are connected in series through the switch 6 and connected to the terminal 7 . That is, the rated voltage appearing at the terminal 7 of the battery module 3(a) is twice that of the high-voltage rated lithium ion secondary battery cell group 1H, that is, twice the rated voltage appearing at the terminal 5 of the battery module 2. high voltage.

Another state of battery module 3, state b, battery module 3(b) turns on or off two high voltage rated lithium ion secondary battery cell groups 1H, respectively, as shown in FIG. They are connected in parallel via the operated switch 6 and connected to the terminal 7 . That is, the rated voltage appearing at the terminal 7 of the battery module 3(b) has the same high voltage rating as the high voltage rated lithium ion secondary battery cell group 1H. If there is an imbalance in remaining capacity between the two lithium ion secondary battery cell groups, connecting in parallel via the switch 6 will balance the remaining capacity of the two lithium ion secondary battery cell groups. do. Although the switch 6 is schematically illustrated as a contact switch in FIG. 4, it is preferable to use a semiconductor switch such as an FET in order to perform switching control of the switch 6 at high speed in controlling the motor system 106, which will be described later. Since the total energization time of the FETs required for balance using the FETs is relatively extremely short compared to the discharge time of the battery module, for example, when the switch 6 is an FET, the energization time of the FETs is also extremely short. The effect of heat generation on the heat generation of the entire system is extremely small, and the additional cost of the FETs contributes very little to the total cost of the system.

Yet another state of the battery module 3, state c, the battery module 3(c), as shown in FIG. 6 is turned off and all parts are electrically cut off. Therefore, since the two lithium ion secondary battery cell groups 1H are in an electrically floating state, the motor system 106, which will be described later, is equipped with deformation and contact of metal parts in the event of a collision accident of an electric vehicle. Reduce the probability of occurrence of a short-circuit current in any one of three independent closed circuits or a short-circuit path across any two of the three closed circuits can.

The motor system 106 has a configuration in which the battery module 2 of the motor system 101 is replaced with the battery module 3 and a main controller 9 is added, as shown in FIG. Main controller 9 communicates with battery module 3U, battery module 3V, and battery module 3W using insulated communication signal 10 to obtain information on each battery module. , to switch to any one of the states a through c. In addition, the main controller 9 uses the insulating communication signal 13 to communicate with the

inverters

6U, 6V, and 6W, respectively, and obtains information on each inverter. The timing of the zero crossing of the AC voltage output of the inverter 6 is detected, and reflected in the balance control between the two lithium ion secondary battery cell groups 1H in the battery module 3, which will be described later.

Motor system 106 supplies DC voltage output from battery module 3U, battery module 3V, and battery module 3W, which have the same configuration as battery module 3, to high-voltage power line 5U, high-voltage power line 5V, and high-voltage power line 5V. 5W to the

inverters

6U, 6V, and 6W. The inverter 6U, the inverter 6V, and the inverter 6W input high-voltage DC voltage from the battery module 3U, the battery module 3V, and the battery module 3W, respectively, converts them to AC voltage, and converts them into desired electrical angles for each phase. Three phase-shifted single-phase AC voltages are applied to the

magnetic pole coils

7U, 7V, and 7W arranged in three phases in the motor to generate a rotating magnetic field between the magnetic pole coils, thereby rotating the rotor. controls the rotation of the

Insulated communication lines 8a, 8b, and 8g communicate between three inverters arranged in independent closed circuits by insulated signals using photocouplers, and output three inverters from the three inverters. is used to shift the phase of the single-phase AC voltage to the desired electrical angle.

Next, the control of the main controller 9 of the motor system 106 will be explained using the flowchart of FIG.

In Step 1, the main controller 9 of the motor system 106 detects the control state of the inverter 6U, the inverter 6V, and the inverter 6W using the insulating communication signal 13, and detects whether the motor is being driven. . When it is determined that the motor is driving, that is, the electric vehicle equipped with the motor system 106 is running or preparing to run, the process proceeds to Step 2, and the three phases belonging to the three phases are connected using the insulating communication signal 10. All of the battery modules 3 are instructed to switch to state a, and all of the three battery modules 3 switch to state a. Here, the output voltage from the terminals 7 of the battery module 3U, the battery module 3V, and the battery module 3W is twice as high as the rated voltage of the lithium ion secondary battery cell group 1H. 6U, inverter 6V, and inverter 6W are uniformly applied.

On the other hand, if the main controller 9 of the motor system 106 determines in Step 1 that the motor is not being driven, that is, if it determines that the electric vehicle equipped with the motor system 106 is stopped, the process proceeds to Step 3. The communication signal 10 is used to instruct all of the three battery modules 3 belonging to three phases to switch to the state b, and all the three battery modules 3 switch to the state b. Carry out charging.

Regarding the charging of the battery modules by the charger, a method of charging a plurality of battery modules according to the conventional technology, for example, a method of connecting a plurality of battery modules in series or in parallel and charging them collectively, or a method of charging a plurality of battery modules individually. In either case, if the voltage of the battery module is increased for the purpose of extending the cruising distance per charge of an electric vehicle, the charging of the charger for charging the battery module with the increased voltage The output voltage rating of the circuit also needs to be increased, and the increase in the output voltage rating of the charging circuit leads to a significant increase in the cost of the charger. On the other hand, in the battery module 3 of the embodiment of the present invention, the rated voltage appearing at the terminal 7 of the battery module 3 can be reduced to half of the normal discharging state a by switching to the former state b in the above Step 3. The output voltage rating of the charging circuit can also be halved, contributing to cost reduction of the charger.

In Step 5, the main controller 9 of the motor system 106 uses the insulating communication signal 10 to detect the states of the three battery modules 3 belonging to the three phases, and sets one of the three phases to the X phase. Select a control target. The selection of the X-phase is preferably performed in descending order of remaining capacity imbalance between the two lithium-ion secondary battery cell groups 1H included in each battery module 3 . Next, in Step 6, the battery module 3X belonging to the X-phase closed circuit is instructed to be switched to the state a, and the battery module X maintains the state a as it was in Step 2, or is changed from Step 10 to be described later. When returned, the battery module 3X switches from state b to state a.

In Step 7, the main controller 9 communicates with the battery module 3X using the insulating communication signal 10 to obtain information from the acceleration sensor 7 of the battery module 3X, and determines whether the rate of change in acceleration is less than a predetermined value. detect whether If it is determined that the rate of change in acceleration is less than a predetermined value, that is, that the electric vehicle is running at a constant speed, the process proceeds to Step 8, in which the insulating communication signal 13 is used to communicate with the inverter 6X, and the inverter 6X outputs. The timing at which the AC voltage reaches zero cross is acquired, and it is detected whether or not it is within a predetermined electrical angle or within a predetermined period of time with the point of time of the zero cross as the midpoint. If it is determined that it is not within the predetermined angle or the time range within the predetermined time with the time of the zero crossing as the midpoint, it returns to Step 6, instructs to switch the battery module 3X to the state a, and the battery module 3X is in the state a. While switching to state a, if it is determined that the state is within a predetermined angle or within a predetermined period of time with the point of time of the zero crossing as the middle point, the process proceeds to step 9, and an instruction is given to switch the battery module 3X to state b. , the battery module 3X is switched to the state b, the two lithium ion secondary battery cell groups 1H are connected in parallel, and the remaining capacities are balanced.

In Step 10, the main controller 9 of the motor system 106 acquires the information of the battery module 3X using the insulating communication signal 10, and balance of the two lithium ion secondary battery cell groups 1H in the battery module 3X is completed. If it is determined that the balance has not been completed, that is, the voltage difference between the two lithium ion secondary battery cell groups 1H is not equal to or less than a predetermined value, the process returns to Step 6 and the balance is completed. Until, that is, until it is determined that the voltage difference between the two lithium ion secondary battery cell groups 1H is equal to or less than a predetermined value, the switching between state a and state b is repeated each time the zero cross timing of

steps

7 and 8 is reached. . The time in the state b is short, but each time the zero cross is repeated multiple times, sufficient current flows between the lithium ion secondary battery cell groups 1H to complete the balance, and the voltages thereof are balanced. . In the embodiment of the present invention, the balance between the two lithium ion secondary battery cell groups 1H was described, but by balancing the lithium ion secondary battery cell groups 1H, the lithium ions contained therein There is also a substantial balancing effect for the individual remaining capacity imbalance of the single cells of the secondary battery.

On the other hand, when the main controller 9 of the motor system 106 determines in Step 10 that the balance has been completed, that is, that the voltage difference between the two lithium ion secondary battery cell groups 1H is equal to or less than a predetermined value, the process proceeds to Step 11. , communicates with the battery module 3X using the insulating communication signal 10 to obtain information from the acceleration sensor 7 of the battery module 3X, detects whether or not the acceleration change rate exceeds a predetermined value, and detects whether the acceleration change rate exceeds a predetermined value. exceeds a predetermined value, i.e., an electric vehicle collision accident has occurred, the process proceeds to Step 12, an instruction is given to switch the battery module 3X to state c, and in Step 12 the battery module 3X is switched to state c. . Here, since the two lithium-ion secondary battery cell groups 1H with high voltage rating are in an electrically floating state, the 3 cells due to deformation and contact of metal parts in the case of a collision accident of the electric vehicle. Reduce the probability of forming a short-circuit path within any one of the closed circuits, or forming a short-circuit path across any two of the three closed circuits. It is possible to prevent the risk of ignition caused by the short-circuit current of the lithium-ion secondary battery. It should be noted that the switching to the state c may be performed not only for the X phase, which is the object of balance control, but also for other phases or all the phases.

Regarding the detection of the rate of change in acceleration described above, when the electric vehicle is accelerated by switching control of state a or state b of the battery module 3X, which is limited to one of the three phases during constant speed running of the electric vehicle after Step 7, and to improve the reliability of the electric vehicle at the time of a collision accident by switching control to the state c after the above Step 11, and the battery module 3X Either a method using the acceleration sensor 7 inside the battery module 3X or a method using an acceleration sensor arranged outside the battery module 3X may be used. Further, the control for switching the battery module 3X to the state c when the acceleration change rate exceeds a predetermined value is not limited to the control method based on the detection and determination by the main controller 9, and the module controller in the battery module 3 It is preferable to employ a method of performing control based on the detection and judgment by 4 in parallel with the control by the main controller 9 to further increase reliability.

The control of Steps 6 to 10 described above will be described below using the time chart diagram of FIG.

In FIG. 8, (i) is the waveform of the output voltage of the inverter 6X, (ii) is the waveform of the input voltage of the inverter 6X, that is, the output voltage of the battery module 3X, and (iii) is the waveform of the two batteries in the battery module 3X. 1 shows the time change of the voltage difference ΔV of the lithium ion secondary battery cell group 1H.

As shown in FIG. 8(i), the output voltage waveform of the inverter 6X is approximately a sine wave of alternating current. That is, it detects and determines that it is within the time range of Tz±t, and switches the output of the battery module 3X from state a to state b in step 9 . At this time, if the rated voltage of the lithium ion secondary battery cell group 1H is V, the output voltage of the battery module 3X is switched from 2V in state a to V in state b. In state b, two lithium-ion secondary battery cell groups 1H are connected in parallel, and current flows between the two lithium-ion secondary battery cell groups 1H. , .DELTA.V in the state a shows a corresponding value, and every time the switching between the state b and the state a is repeated, the .DELTA.V in the state a gradually decreases and approaches 0, and finally, in the state b and the state a, .DELTA.V= 0, the remaining capacity imbalance between the two lithium ion secondary battery cell groups 1H is eliminated, the discharge performance is maximized, and this control is sequentially applied to all the battery modules 3 belonging to the three-phase closed circuit. Applied, it contributes to the extension of the cruising range per charge of electric vehicles. Further, within the time range in which the battery module 3X belonging to the X phase is in the state b, the output voltage of the X-phase inverter 6X, which is limited to a specific phase among the three phases, is near zero cross, that is, approximately 0. Since there is, and the two phases other than the X phase are in the state a, the control of the three-phase motor is not affected.

As described above, in the electric vehicle equipped with the motor system 106, the rated voltage of the three battery modules is increased, and the remaining capacity imbalance of the lithium-ion battery cell group in the battery module is eliminated. By maximizing the discharge capacity of the battery module, it is possible to further extend the cruising range per charge of an electric vehicle, reduce the total cost of electric vehicle chargers, and improve reliability in the event of a collision. .

In an electric vehicle equipped with the motor system of the present invention, even if the rated voltage of the battery power supply is doubled compared to the conventional one, the discharge capacity of the lithium ion secondary battery can be maximized without causing the remaining capacity imbalance. can be extended, and the cruising range per charge can be further extended while suppressing cost increases. In addition, even if the rated voltage of the battery power supply is increased, it is possible to prevent the formation of chaotic short circuits that cannot occur due to the original circuit configuration of the prior art due to the deformation and contact of metal parts, etc., in the event of a collision accident of an electric vehicle. .

Similarly, in a hybrid vehicle equipped with the motor system of the present invention, it is possible to extend the discharge time from the battery power supply to the motor, thereby realizing further improvement in fuel efficiency while suppressing cost increases.
Furthermore, the reduction in the cost of the charger makes it possible to reduce the total system cost of the electric vehicle or the plug-in hybrid vehicle.

Although the present embodiment has been described above, the above embodiment is intended to facilitate understanding of the present invention, and is not intended to limit and interpret the present invention. The present invention can be modified and improved without departing from its spirit, and the present invention also includes equivalents thereof.

3 battery module 9 main controller 106 motor system

Claims

a battery cell group;
Any one state of a first state in which the battery cell groups are connected in series, a second state in which the battery cell groups are connected in parallel, or a third state in which all current paths between the battery cell groups are cut off. a switching circuit that switches to
an acceleration sensor;
with
A battery module that changes to one of the first state through the third state according to the acceleration change rate detected by the acceleration sensor.
A motor system that drives a motor with a battery power supply,
a motor that rotates a rotor by applying AC voltages to a plurality of excitation coils or magnetic pole coils;
a plurality of battery modules;
with
The battery module and the excitation coil or the magnetic pole coil of the motor constitute a plurality of independent closed circuits via an inverter circuit,
When it is detected that the rate of change in acceleration is less than a predetermined value in at least one closed circuit among the plurality of closed circuits, and when the zero cross point of the AC voltage output by the inverter circuit is set as a midpoint the battery module is in the second state when the time range is equal to or less than the electrical angle of
if the time is outside the time range equal to or less than a predetermined electrical angle centered at the zero cross point, the battery module is placed in the first state;
A motor system in which the battery module is placed in the third state when a state in which the rate of change in acceleration is equal to or greater than a predetermined value is detected.