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EP-3971009-B1 - SYSTEM FOR BATTERY OF CAR HAVING ENERGY STORAGE PART

EP3971009B1EP 3971009 B1EP3971009 B1EP 3971009B1EP-3971009-B1

Inventors

  • MOON, HYO-SIK
  • MIN, KYUNG-IN

Dates

Publication Date
20260513
Application Date
20210802

Claims (15)

  1. A system for a battery of a car, the system comprising: a battery assembly (10) including at least one first battery module (11) and at least one second battery module (12); a first relay (R1) in which a first relay node is electrically connected between a first contact point (a) to which a first point (p1) of the second battery module (12) is connected and a second contact point (b) to which a second point (p2) of the second battery module (12) is connected, the first relay (R1) configured to control closing and opening between the first relay node and the first contact point (a) and to control closing and opening between the first relay node and the second contact point (b); a second relay (R2) in which a second relay node is electrically connected between the second contact point (b) and a third contact point (c) to which a first point (p4) of the first battery module (11) is connected, the second relay (R2) configured to control closing and opening between the second relay node and the second contact point (b) and to control closing and opening between the second relay node and the third contact point (c); a third relay (R3) electrically connected between the second point (p2) of the second battery module (12) and a second point (p3) of the first battery module (11), the third relay (R3) configured to control closing and opening between the second point (p2) of the second battery module (12) and the second point (p3) of the first battery module (11); a converter (40) configured to: convert voltage input through an input terminal (43) connected to the first relay node and the second relay node; and supply the converted voltage to a low-voltage electronic product (50) through an output terminal (44); a sixth relay (R6) configured to control between the second point (p3) of the first battery module (11) and the output terminal (44); a seventh relay (R7) configured to control between the first point (p4) of the first battery module (11) and the output terminal (44); an energy storage part (80) connected to the output terminal (44); and a battery management system (70) configured to control the first relay (R1), the second relay (R2), the third relay (R3), the sixth relay (R6), and the seventh relay (R7), and the energy storage part (80) according to a driving condition of the car and energy storage amounts of the first battery module (11) and the second battery module (12), wherein the battery management system (70) is configured to: perform a start mode control until a driving start from a key-off state of the car; determine whether to use the first battery module (11) and the second battery module (12) or whether to use only the first battery module (11) in the key-off state of the car; when it is determined that both the first battery module (11) and the second battery module (12) are used, close the first relay node of the first relay (R1) and the first contact point (a) and close the second relay node of the second relay (R2) and the second contact point (b); open both ends of the sixth relay (R6) and the seventh relay (R7); close both ends of the third relay (R3) to close the second point (p2) of the second battery module (12) and the second point (p3) of the first battery module (11); apply the power of the energy storage part (80) to the second relay (R2) to close the second relay node of the second relay (R2) to the third contact point (c); and apply the power supplied from the first battery module (11) and the second battery module (12) to a motor control unit (20).
  2. The system of claim 1, wherein the first relay node and the second relay node are connected to an inverter, the inverter configured to convert and supply battery power to a driving motor (30) or an input terminal of the motor control unit (20) having the inverter, respectively.
  3. The system of claim 1 or 2, wherein, when it is determined that only the second battery module (12) is used, the battery management system (70) is configured to: close the first relay node of the first relay (R1) and the first contact point (a); close the second relay node of the second relay (R2) and the second contact point (b); and apply single power of only the second battery module (12) to the motor control unit (20).
  4. The system of one of claims 1 to 3, wherein, when determining whether to use the first battery module (11) and the second battery module (12), the battery management system (70) is configured to: determine whether the energy capacity of the first battery module (11) is equal to or greater than a predetermined reference capacity; when the energy capacity of the first battery module (11) is equal to or greater than the predetermined reference capacity, use both the first battery module (11) and the second battery module (12); and when the energy capacity of the first battery module (11) is less than the predetermined reference capacity, use only the second battery module (12).
  5. The system of one of claims 1-4, wherein the battery management system (70) is configured to: perform a driving mode control of switching a common using state of the first battery module (11) and the second battery module (12) to a single using state of the second battery module (12) while the car is driven; when the first relay node of the first relay (R1) is closed to the first contact point (a), determine whether switching the common using state of the first battery module (11) and the second battery module (12) to the second battery module (12) alone using state is required; when it is determined that the switching to the second battery module (12) alone using state is required, supply the power of the energy storage part (80) to the second relay (R2) to close the second relay node and the second contact point (b); open both ends of the third relay (R3); close both ends of the sixth relay (R6) and the seventh relay (R7); and supply the power of only the second battery module (12) to the motor control unit (20) and supply the power of the first battery module (11) to the low-voltage electronic product (50) to drive the low-voltage electronic product (50).
  6. The system of claim 5, wherein determining whether the switching the common using state of the first battery module (11) and the second battery module (12) to the second battery module (12) alone using state is required comprises: when the converter (40) has a failure or a capacity deviation of the first battery module (11) out of an allowable range occurs, determine that the switching the common using state to the second battery module (12) alone using state is required.
  7. The system of one of claims 1-6, wherein the battery management system (70) is configured to: perform a driving mode control of switching a common using state of the first battery module (11) and the second battery module (12) to a single using state of the second battery module (12) while the car is driven; when the first relay node of the first relay (R1) is closed to the first contact point (a), determine whether switching the module common using state to the second battery module (12) alone using state is required; when it is determined that the switching to the second battery module (12) alone using state is required, open the second relay node of the second relay (R2) and the third contact point (c) and open both ends of the third relay (R3); close both ends of the sixth relay (R6) and the seventh relay (R7) by supplying the power of the energy storage part (80) to the sixth relay (R6) and the seventh relay (R7); close the second relay node of the second relay (R2) and the second contact point (b); supply the power of only the second battery module (12) to the motor control unit (20); and supply the power of the first battery module (11) to the low-voltage electronic product (50) to drive the low-voltage electronic product (50).
  8. The system of one of claims 1-7, wherein the battery management system (70) is configured to: perform a driving mode control of switching the second battery module (12) alone using state to the module common using state of the first battery module (11) and the second battery module (12) while the car is driven; when the first relay node of the first relay (R1) is closed to the first contact point (a), and the second relay node of the second relay (R2) is closed to the second contact point (b), open both ends of the third relay (R3), and close both ends of the sixth relay (R6) and the seventh relay (R7); determine whether the switching of the second battery module (12) alone using state to the module common using state is required; when it is determined that the switching to the module common using state is required, open both ends of the sixth relay (R6) and the seventh relay (R7); close the second relay node and the third contact point (c) by applying the power of the energy storage part (80) to the second relay (R2); close both ends of the third relay (R3) by applying the power of the energy storage part (80) to the third relay (R3); and apply the power supplied from the first battery module (11) and the second battery module (12) to the motor control unit (20).
  9. The system of claim 8, wherein determining whether the switching of the second battery module (12) alone using state to the module common using state is required comprises: when the failure of the converter (40) is released and the converter (40) normally operates or when capacity balancing of the energy capacity of the first battery module (11) is completed and the capacity deviation of the first battery module (11) returns within the allowable range, determine that the switching to the module common using state of the first battery module (11) and the second battery module (12) is required.
  10. The system of one of claims 1-9, further comprising: a charging part (60) configured to: receive power from outside; and convert the received power into power for battery charging and provide the converted power; a fourth relay (R4) connected between the charging part (60) and the first relay node, the fourth relay (R4) configured to control between the charging part (60) and the first relay node; and a fifth relay (R5) connected between the charging part (60) and the second relay node, the fifth relay (R5) configured to control between the charging part (60) and the second relay node, wherein the battery management system (70) is configured to: perform a control of an external charging mode of commonly charging the first battery module (11) and the second battery module (12) by the power supplied from the charging part (60); determine whether to perform an operation of commonly charging the first battery module (11) and the second battery module (12) or whether to perform an operation of individually charging the first battery module (11) and the second battery module (12), respectively, in the key-off state of the car; when it is determined that a module common charging operation of commonly charging the first battery module (11) and the second battery module (12) is performed, close the first relay node of the first relay (R1) and the first contact point (a) and close the second relay node of the second relay (R2) and the second contact point (b); open both ends of the sixth relay (R6) and the seventh relay (R7) close both ends of the third relay (R3) to close the second point (p2) of the second battery module (12) and the second point (p3) of the first battery module (11); apply the power of the energy storage part (80) to the second relay (R2) to close the second relay node of the second relay (R2) to the third contact point (c); and close both ends of the fourth relay (R4) and the fifth relay (R5) to charge the first battery module (11) and the second battery module (12) by the power provided from the charging part (60).
  11. The system of claim 10, wherein, when it is determined that the operation of individually charging the first battery module (11) and the second battery module (12) is performed, the battery management system (70) is configured to: close the first relay node of the first relay (R1) and the first contact point (a); close the second relay node of the second relay (R2) and the second contact point (b); close both ends of the fourth relay (R4) and the fifth relay (R5); charge the second battery module (12) by the power provided from the charging part (60); and supply the power provided from the charging part (60) to the first battery module (11) from the converter (40) through the sixth relay (R6) and the seventh relay (R7) to charge the first battery module (11).
  12. The system of claim 10 or 11, wherein when determining whether module common charging or module individual charging is performed, the battery management system (70) is configured to: determine whether the energy capacity of the first battery module (11) is equal to or greater than a predetermined charging reference capacity; commonly charge the first battery module (11) and the second battery module (12) when it is determined that the energy capacity is equal to or greater than the charging reference capacity; and individually charge each of the first battery module (11) and the second battery module (12) when it is determined that the energy capacity is less than the charging reference capacity.
  13. The system of one of claims 1-12, wherein the battery management system (70) is configured to: perform a key-off switching mode control of switching the first battery module (11) and second battery module (12) common using state to the key-off state when driving or charging the car; when both ends of the sixth relay (R6) and the seventh relay (R7) are opened, respectively, switch the first relay node of the first relay (R1) and the second relay node of the second relay (R2) to a floating state and open both ends of the third relay (R3); supply the power of the energy storage part (80) to the sixth relay (R6) and the seventh relay (R7) to close both ends of the sixth relay (R6) and the seventh relay (R7); and switch the common using state to the key-off state when the low-voltage power is supplied by the low voltage of the first battery module (11).
  14. The system of one of claims 1-13, wherein the battery management system (70) is configured to: perform a key-off switching mode control of switching the second battery module (12) alone using state to the key-off state when driving or charging the car; when both ends of the third relay (R3) are opened and the second point (p2) of the second battery module (12) and the second point (p3) of the first battery module (11) are opened, and both ends of the sixth relay (R6) and the seventh relay (R7) are closed, respectively, switch the first relay node of the first relay (R1) and the second relay node of the second relay (R2) to the floating state; and switch the second battery module (12) alone using state to the key-off state when the power of the first battery module (11) is supplied.
  15. The system of one of claims 1-14, wherein the converter (40) further comprises: a low voltage DC-DC converter (41) configured to convert DC high voltage into DC low voltage; and a solar DC-DC converter (42) configured to convert power supplied from a solar cell installed into the DC low voltage, wherein the battery management system (70) is configured to: perform a control of a supplementary charging mode of charging the first battery module (11) when a capacity of the first battery module (11) is equal to or less than a predetermined level in a key-off situation of the car; when the first relay node of the first relay (R1) and the second relay node of the second relay (R2) are in the floating state, open both ends of the third relay (R3), and close both ends of the sixth relay (R6) and the seventh relay (R7) to supply the low voltage power by the low voltage of the first battery module (11); determine whether the energy capacity of the first battery module (11) is equal to or less than the predetermined level; when it is determined that the energy capacity of the first battery module (11) is equal to or less than the predetermined level, determine that supplementary charging of the first battery module (11) is required; close the first relay node of the first relay (R1) and the first contact point (a); close the second relay node of the second relay (R2) and the second contact point (b); apply the power from the second battery module (12) by the converter (40); and supply the low-voltage power from the low voltage DC-DC converter (41) to the first battery module (11) to supplementally charge the first battery module (11), wherein, optionally, when it is determined that the energy capacity of the first battery module (11) is not equal to or less than the predetermined level, the battery management system (70) is configured to charge supplementally the first battery module (11) with the low-voltage power supplied by the solar DC-DC converter (42).

Description

TECHNICAL FIELD The present disclosure relates to a system for a battery of a car. BACKGROUND In general, eco-friendly cars (hybrid cars, electric cars, fuel cell cars, etc.) equipped with electric motors for providing driving power of wheels are provided with high voltage batteries to provide high voltage energy for driving the electric motors. Here, the high voltage generally means relatively higher voltage than a battery (in general, having a voltage of 11 to 14 V) provided for starting an engine driving car or supplying power to electronic product loads. Accordingly, the eco-friendly car generally includes a high-voltage battery for driving the electric motor and a low-voltage battery for supplying the power to the electronic product load separately from each other. Managing mutual individual power systems by separating the high-voltage battery and the low-voltage battery not only results in system bloating, but also results in large loss in terms of efficiency. In order to solve this, proposed is a high voltage-low voltage integrating system which uses some of a plurality of battery modules constituting the high-voltage battery for supplying low-voltage power by considering that one battery assembly is implemented by a plurality of cells or modules. However, the conventional proposed high voltage-low voltage integrating system causes an unbalance of a charge state among the plurality of battery modules provided in one battery assembly, and as a result, there is a concern that efficiency or robustness of the system will deteriorate and instability of the car will be caused. In the conventional proposed high voltage-low voltage integrating system, there was also a risk of instantaneous insulation breakdown when controlling high voltage-low voltage relays according to a driving situation of the car. EP 3 473 487 A1 discloses that a battery system for a vehicle includes: a battery assembly including at least one first battery module and at least one second battery module; a first relay being closed/opened between a first node and one of a first end of the first battery module and a first end of the second battery module being connected to a second end of the first battery module; a second relay being closed/opened between a second node and a second end of the second battery module; a converter converting a voltage between the nodes; a third relay being closed/opened between the converter and the first end of the first battery module; a fourth relay being closed/opened between the first end of the first battery module and a ground; and a battery manager controlling the relays based on a driving condition of the vehicle and energy storage amounts of the modules. EP 2 722 961 A1 discloses that a first opening/closing device is configured to include a precharging relay and a limiting resistor connected in series between a first power storage unit and a first pair of power lines. A second opening/closing device is configured not to include the precharging relay and the limiting resistor. When precharging a capacitor using a second power storage unit, a control device controls opening/closing of first to fourth opening/closing devices so as to form an electric conduction path extending between the second power storage unit and the capacitor via the precharging relay and the limiting resistor. SUMMARY The present invention provides a configuration of a system for a battery of a car for enhancing efficiency and robustness of a system by resolving an unbalance of a charge state among a plurality of battery modules provided in one battery assembly and preventing an insulation breakdown which may instantaneously occur at the time of controlling high voltage-low voltage relays according to a driving situation of the car. Various embodiments provide a system for a battery of a car according to claim 1. Further embodiments are described in the dependent claims. An exemplary embodiment of the present invention provides a system for a battery of a car having an energy storage part configured to include a battery assembly having a first battery module and a second battery module, relays installed between contact points connected with respective terminals of the first battery module and the second battery module and controlling power supply to a driving motor of the car, a converter converting voltage input from the first battery module and the second battery module and supplying the converted voltage to a low-voltage electronic product, an energy storage part connected to an output terminal of the converter, and a battery management system controlling the same. According to an exemplary embodiment of the present invention, a system for a battery of a car having an energy storage part prevents an instantaneous insulation breakdown which occurs at the time of driving a relay by adding the energy storage part to an LDC output terminal and enables a car operation even in a fail-safe situation such as a failure situation of an