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CN-114977365-B - Battery system and control method

CN114977365BCN 114977365 BCN114977365 BCN 114977365BCN-114977365-B

Abstract

A battery system and a control method are provided. The battery charging device is provided with a charging device (200), a plurality of battery modules (110) - (130) which can be connected in parallel to the charging device (200), and a control device (400), wherein each of the plurality of battery modules is provided with a battery, the control device (400) obtains the voltage value of each battery of the plurality of battery modules when receiving a charging command, determines a 1 st battery (E1) with the lowest voltage value and a2 nd battery (E2) with the lowest voltage value and starts charging the 1 st battery (E1), and after charging the 1 st battery (E1), when the difference value between the voltage value of the 1 st battery module (110) and the voltage value (V2) of the 2 nd battery (E2) is less than or equal to a 1 st threshold value, starts charging the 2 nd battery (E2).

Inventors

  • FURUKAWA KIMIHIKO

Assignees

  • 泰星能源解决方案有限公司

Dates

Publication Date
20260505
Application Date
20220224
Priority Date
20210225

Claims (14)

  1. 1.A battery system is provided with: a charging device; a plurality of battery modules connectable in parallel with the charging device, and The control device is used for controlling the control device, The plurality of battery modules each have a battery, The control device: When a charge command is received, the voltage values of the batteries of the plurality of battery modules are acquired, a1 st battery with the lowest voltage value and a2 nd battery with the lowest voltage value are determined, The charging of the 1 st battery is started, After the charging of the 1 st battery is started, when a difference value between a voltage value of a1 st battery module of the 1 st battery and a voltage value of the 2 nd battery or a difference value between the voltage value of the 1 st battery and the voltage value of the 2 nd battery becomes equal to or less than a1 st threshold value, The control device starts charging of the 1 st battery so that a voltage value of the 1 st battery module or a voltage value of the 1 st battery increases linearly until a predetermined period elapses from when the charge command is received, when the difference value is greater than the 1 st threshold but equal to or less than a3 rd threshold that is greater than the 1 st threshold, when the charge command is received.
  2. 2. The battery system of claim 1, wherein, The plurality of battery modules includes 3 battery modules, The control device: in the case where the charge instruction is received, a3 rd battery having a3 rd low voltage value is determined together with the 1 st battery and the 2 nd battery, After the charging of the 2 nd battery is started, when a difference value between a voltage value of the 2 nd battery module of the 2 nd battery and a voltage value of the 3 rd battery or a difference value between a voltage value of the 2 nd battery and a voltage value of the 3 rd battery becomes a2 nd threshold value or less, the charging of the 3 rd battery is started.
  3. 3. The battery system according to claim 1 or 2, wherein, The control device starts charging of the 1 st battery and charging of the 2 nd battery when the difference value is equal to or smaller than the 1 st threshold upon receiving the charging instruction.
  4. 4. The battery system according to claim 1 or 2, wherein, The control device limits the charging current by the control device when the number of the batteries to be charged by the charging device is equal to or less than a predetermined number.
  5. 5. The battery system of claim 1, wherein, It is also provided with a load which, The plurality of battery modules can be connected in parallel with the load, The control device: when a discharge command is received, the voltage values of the batteries of the plurality of battery modules are acquired, a1 st discharge battery with the highest voltage value and a2 nd discharge battery with the highest voltage value are determined, The discharge of the 1 st discharge cell is started, After the discharge of the 1 st discharge battery is started, when a difference value between a voltage value of the 1 st discharge battery module including the 1 st discharge battery and a voltage value of the 2 nd discharge battery or a difference value between a voltage value of the 1 st discharge battery and a voltage value of the 2 nd discharge battery becomes a 1 st discharge threshold or less, the discharge of the 2 nd discharge battery is started.
  6. 6. The battery system of claim 5, wherein, The plurality of battery modules includes 3 battery modules, The control device: in the case where the discharge instruction is received, a3 rd discharge cell having a3 rd high voltage value is determined together with the 1 st discharge cell and the 2 nd discharge cell, After the discharge of the 2 nd discharge battery is started, when a difference value between a voltage value of a 2 nd discharge battery module including the 2 nd discharge battery and a voltage value of the 3 rd discharge battery or a difference value between a voltage value of the 2 nd discharge battery and a voltage value of the 3 rd discharge battery becomes a 2 nd discharge threshold value or less, the discharge of the 3 rd discharge battery is started.
  7. 7. The battery system according to claim 5 or 6, wherein, The control device starts discharging the 1 st discharge battery and discharging the 2 nd discharge battery when the difference value is equal to or smaller than the 1 st discharge threshold when the discharge command is received.
  8. 8. The battery system according to claim 5 or 6, wherein, The control device limits a discharge current by the control device when the number of batteries discharging the load is equal to or less than a predetermined number.
  9. 9. The battery system according to claim 1 or 2, wherein, The 1 st threshold is calculated from a resistance value of the 1 st battery module and a current value allowed to flow between the 1 st battery module and a2 nd battery module including the 2 nd battery.
  10. 10. The battery system according to claim 5 or 6, wherein, The 1 st discharge threshold is calculated from a resistance value of the 1 st discharge battery module and a current value allowed to flow between the 1 st discharge battery module and a2 nd discharge battery module including the 2 nd discharge battery.
  11. 11. The battery system of claim 9, wherein, The resistance value is a combination of an internal resistance value of the 1 st cell and a resistance value of a component corresponding to the 1 st cell.
  12. 12. The battery system of claim 10, wherein, The resistance value is a combination of an internal resistance value of the 1 st discharge cell and a resistance value of a component corresponding to the 1 st discharge cell.
  13. 13. A control method of a battery system comprising a charging device and a plurality of battery modules connectable in parallel with the charging device, The plurality of battery modules each have a battery, The control method comprises the following steps: When a charging instruction is received, acquiring voltage values of batteries of the battery modules, and determining a1 st battery with the lowest voltage value and a2 nd battery with the lowest voltage value; Starting the charging of the 1 st battery, and After the charging of the 1 st battery is started, when a difference value between a voltage value of a1 st battery module of the 1 st battery and a voltage value of the 2 nd battery or a difference value between the voltage value of the 1 st battery and the voltage value of the 2 nd battery becomes equal to or less than a1 st threshold value, The control method starts charging of the 1 st battery so that a voltage value of the 1 st battery module or a voltage value of the 1 st battery increases linearly until a predetermined period elapses from when the charge command is received, when the difference value is greater than the 1 st threshold but equal to or less than a3 rd threshold that is greater than the 1 st threshold, when the charge command is received.
  14. 14. The control method according to claim 13, wherein, The battery system further includes a load, the plurality of battery modules being connectable in parallel with the load, The control method comprises the following steps: When a discharging instruction is received, obtaining the voltage values of the batteries of the battery modules, and determining a1 st discharging battery with the highest voltage value and a2 nd discharging battery with the highest voltage value; starting the discharge of the 1 st discharge cell, and After the discharge of the 1 st discharge battery is started, when a difference value between a voltage value of the 1 st discharge battery module including the 1 st discharge battery and a voltage value of the 2 nd discharge battery or a difference value between a voltage value of the 1 st discharge battery and a voltage value of the 2 nd discharge battery becomes a 1 st discharge threshold or less, the discharge of the 2 nd discharge battery is started.

Description

Battery system and control method Technical Field The present disclosure relates to a battery system and a control method. Background In recent years, demand for moving bodies (for example, vehicles such as EVs (ELECTRIC VEHICLE, electric vehicles) and ships) powered by electric power has increased. In a battery pack system (hereinafter also referred to as "battery system") used for such a mobile body, a high-capacity structure in which a plurality of battery packs (hereinafter also referred to as "batteries") are connected in parallel is employed in order to enable traveling over a long distance or sailing. The plurality of batteries are charged by the charging device when the mobile body is parked or berthed, and discharge the propeller of the mobile body or the load in the mobile body when the mobile body is driven or sailed. However, a voltage difference may occur between the plurality of batteries due to variations in characteristics of the battery cells or the like. When a plurality of batteries generating a voltage difference are connected in parallel, a so-called "cross current" occurs in which a current flows from a battery having a high voltage value to a battery having a low voltage value among the plurality of batteries. In japanese patent application laid-open No. 2011-182623, a battery system for preventing such occurrence of lateral flow is proposed. In this battery system, for example, when a plurality of batteries are charged or when a plurality of batteries are discharged, a process for equalizing the voltages of the plurality of batteries is performed. In this battery system, an equalization resistor is provided between the batteries. Then, the equalization process is performed by flowing the current from the battery having a high voltage value to the battery having a low voltage value through the equalization resistor. Disclosure of Invention However, this patent document has a problem that the system is increased in size because it is required to have an equalization resistor. Further, since the current through the resistor is used, the current becomes small when the voltage difference is small, and the time required for equalization becomes long. An object of the present disclosure is to provide a battery system and a control method that perform voltage equalization of a battery in a short time without increasing the size of the battery system. According to an aspect of the present disclosure, a battery system includes a charging device, a plurality of battery modules connectable in parallel to the charging device, and a control device. The plurality of battery modules each have a battery. When receiving the charge command, the control device obtains the voltage values of the batteries of the plurality of battery modules, and identifies the 1 st battery having the lowest voltage value and the 2 nd battery having the lowest voltage value. First, the control device starts charging of the 1 st battery. Next, the control device starts charging of the 2 nd battery when a difference value between the voltage value of the 1 st battery module including the 1 st battery and the voltage value of the 2 nd battery or a difference value between the voltage value of the 1 st battery and the voltage value of the 2 nd battery becomes 1 st threshold or less after starting charging of the 1 st battery. According to another aspect of the present disclosure, a battery system includes a load, a plurality of battery modules connectable in parallel to the load, and a control device. The plurality of battery modules each have a battery. When receiving the discharge command, the control device obtains the voltage values of the batteries of the plurality of battery modules, and identifies the 1 st battery with the highest voltage value and the 2 nd battery with the highest voltage value. First, the control device starts discharging the 1 st battery. Next, after starting the discharge of the 1 st battery, the control device starts the discharge of the 2 nd battery when the difference value between the voltage value of the 1 st battery module including the 1 st battery and the voltage value of the 2 nd battery or the difference value between the voltage value of the 1 st battery and the voltage value of the 2 nd battery becomes the 1 st threshold or less. According to another aspect of the present disclosure, a control method is a control method of a battery system including a charging device and a plurality of battery modules connectable in parallel with respect to the charging device. The plurality of battery modules each have a battery. In the control method, when a charge command is received, the voltage values of the batteries of the plurality of battery modules are acquired, and the 1 st battery having the lowest voltage value and the 2 nd battery having the lowest voltage value are determined. First, in the control method, charging of the 1 st battery is started. Next, in the control method, after the char