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EP-4737651-A1 - ELECTRIC WORK MACHINE AND METHOD FOR CONTROLLING ELECTRIC WORK MACHINE

EP4737651A1EP 4737651 A1EP4737651 A1EP 4737651A1EP-4737651-A1

Abstract

To notify the proper temperature to a human operator based on temperature of the battery assembly detected by a plurality of temperature detectors. An electric working machine (1) includes a battery assembly (30), an electric actuator (9) to be actuated by electricity supplied by the battery assembly, a working device (20) to be actuated by the electric actuator being driven, a plurality of temperature detectors (31b, 31c, 31d, 32b, 32c, 32d) to each detect a temperature of the battery assembly, a controller (7) configured or programmed to calculate a first temperature (T_show) of the battery assembly based on temperatures detected by the plurality of temperature detectors, and a display (60) to display the first temperature calculated by the controller. The controller is configured or programmed to calculate the first temperature based on a lowest temperature (T_min) of the temperatures detected by the plurality of temperature detectors, a highest temperature (T_max) of the temperatures detected by the plurality of temperature detectors, and a weighting value to assign weights such that a weight assigned to the lowest temperature increases as the lowest temperature decreases.

Inventors

  • ITO, JUNKI

Assignees

  • KUBOTA CORPORATION

Dates

Publication Date
20260506
Application Date
20240521

Claims (9)

  1. An electric working machine comprising: a battery assembly; an electric actuator to be actuated by electricity supplied by the battery assembly; a working device to be actuated by the electric actuator being driven; a plurality of temperature detectors to each detect a temperature of the battery assembly; a controller configured or programmed to calculate a first temperature of the battery assembly based on temperatures detected by the plurality of temperature detectors; and a display to display the first temperature calculated by the controller; wherein the controller is configured or programmed to calculate the first temperature based on a lowest temperature of the temperatures detected by the plurality of temperature detectors, a highest temperature of the temperatures detected by the plurality of temperature detectors, and a weighting value to assign weights such that a weight assigned to the lowest temperature increases as the lowest temperature decreases.
  2. The electric working machine according to claim 1, wherein the controller is configured or programmed to: when the lowest temperature is lower than a first predetermined value, determine the lowest temperature as the first temperature; when the lowest temperature is equal to or higher than a second predetermined value, determine the highest temperature as the first temperature; and when the lowest temperature is equal to or higher than the first predetermined value and lower than the second predetermined value, calculate the first temperature based on the lowest temperature, the highest temperature, and the weighting value.
  3. The electric working machine according to claim 1, wherein the weighting value includes a first weighting value and a second weighting value; the first weighting value by which the lowest temperature is multiplied increases as the lowest temperature decreases; and the second weighting value by which the highest temperature is multiplied increases as the lowest temperature increases.
  4. The electric working machine according to claim 1, wherein the plurality of temperature detectors are provided at respective different portions in or on the battery assembly.
  5. The electric working machine according to claim 4, wherein the battery assembly includes a plurality of battery cells; and the plurality of temperature detectors are provided in or on respective different ones of the plurality of battery cells.
  6. The electric working machine according to claim 1, wherein the controller is configured or programmed to: when the lowest temperature is lower than a first predetermined value, control, based on the lowest temperature, at least one of a charging current during charging of the battery assembly or a discharge current during discharging of the battery assembly; and when the highest temperature is equal to or higher than a second predetermined value, control, based on the highest temperature, at least one of the charging current or the discharge current.
  7. The electric working machine according to claim 1, wherein the controller is configured or programmed to: calculate, separately from the first temperature, a second temperature for use in controlling the battery assembly; and based on the second temperature, control at least one of a charging current during charging of the battery assembly or a discharge current during discharging of the battery assembly.
  8. The electric working machine according to claim 7, wherein an upper limit of the charging current and an upper limit of the discharge current are defined such that upper limits of the charging current correspond to temperatures of the battery assembly and upper limits of the discharge current correspond to the temperatures of the battery assembly; and the controller is configured or programmed to calculate, as the second temperature, a temperature corresponding to a lower one of the upper limit corresponding to the highest temperature or the upper limit corresponding to the lowest temperature.
  9. A method of controlling an electric working machine, the electric working machine including: a battery assembly; an electric actuator to be actuated by electricity supplied by the battery assembly; a working device to be actuated by the electric actuator being driven; a plurality of temperature detectors to each detect a temperature of the battery assembly; a display to display the temperature of the battery assembly; and a controller configured or programmed to calculate a first temperature to be displayed by the display; the method comprising the steps of: determining a lowest temperature and a highest temperature of temperatures detected by the plurality of temperature detectors; and calculating the first temperature based on the lowest temperature, the highest temperature, and a weighting value to assign weights such that a weight assigned to the lowest temperature increases as the lowest temperature decreases.

Description

Technical Field The present invention relates to electric working machines each actuated by electricity of a battery assembly and methods of controlling electric working machines. Background Art Patent Literature 1 discloses an electric working machine including an electric motor, a battery assembly to supply electricity to the electric motor, a hydraulic pump driven by the electric motor to deliver hydraulic fluid, a hydraulic device driven by the hydraulic fluid, and a working device actuated by the hydraulic device. The electric working machine, when the battery assembly is running low, may perform fast charging using an external charger. Citation List Patent Literature PTL 1: Japanese Unexamined Patent Application Publication No. 2021-80703 Summary of Invention Technical Problem Some battery assemblies include a plurality of temperature detectors to detect the temperature of the battery assembly. However, the detected temperatures may differ depending on the attached positions of the temperature detectors. In this case, the displayed temperature of the battery assembly may cause misunderstanding to the user. The present invention was made to solve the above issues in the related art, and it is an object of the present invention is to, in an electric working machine, provide a notification of an appropriate temperature to the user based on the temperatures of the battery assembly detected by a plurality of temperature detectors. Solution to Problem An electric working machine according to an example embodiment of the present invention includes a battery assembly, an electric actuator to be actuated by electricity supplied by the battery assembly, a working device to be actuated by the electric actuator being driven, a plurality of temperature detectors to each detect a temperature of the battery assembly, a controller configured or programmed to calculate a first temperature of the battery assembly based on temperatures detected by the plurality of temperature detectors, and a display to display the first temperature calculated by the controller, wherein the controller is configured or programmed to calculate the first temperature based on a lowest temperature of the temperatures detected by the plurality of temperature detectors, a highest temperature of the temperatures detected by the plurality of temperature detectors, and a weighting value to assign weights such that a weight assigned to the lowest temperature increases as the lowest temperature decreases. The controller may be configured or programmed to, when the lowest temperature is lower than a first predetermined value, determine the lowest temperature as the first temperature, when the lowest temperature is equal to or higher than a second predetermined value, determine the highest temperature as the first temperature, and, when the lowest temperature is equal to or higher than the first predetermined value and lower than the second predetermined value, calculate the first temperature based on the lowest temperature, the highest temperature, and the weighting value. The weighting value may include a first weighting value and a second weighting value, the first weighting value by which the lowest temperature is multiplied may increase as the lowest temperature decreases, and the second weighting value by which the highest temperature is multiplied may increase as the lowest temperature increases. The plurality of temperature detectors may be provided at respective different portions in or on the battery assembly. The battery assembly may include a plurality of battery cells, and the plurality of temperature detectors may be provided in or on respective different ones of the plurality of battery cells. The controller may be configured or programmed to, when the lowest temperature is lower than a first predetermined value, control, based on the lowest temperature, at least one of a charging current during charging of the battery assembly or a discharge current during discharging of the battery assembly, and, when the highest temperature is equal to or higher than a second predetermined value, control, based on the highest temperature, at least one of the charging current or the discharge current. The controller may be configured or programmed to calculate, separately from the first temperature, a second temperature for use in controlling the battery assembly, and, based on the second temperature, control at least one of a charging current during charging of the battery assembly or a discharge current during discharging of the battery assembly. An upper limit of the charging current and an upper limit of the discharge current may be defined such that upper limits of the charging current correspond to temperatures of the battery assembly and upper limits of the discharge current correspond to the temperatures of the battery assembly, and the controller may be configured or programmed to calculate, as the second temperature, a temperature correspon