Method and device for determining degradation state of electrical storage device in hybrid construction equipment

• US 8,362,786 B2
• Filed: 03/16/2009
• Issued: 01/29/2013
• Est. Priority Date: 03/21/2008
• Status: Expired due to Fees

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Endou, Takayoshi, Sato, Tomohisa, Yamane, Jun
• Primary Examiner(s): Nguyen, Vincent Q
• Application Number:
  US12/933,233
• Publication Number:
  US 20110018551A1
• Time in Patent Office: 1,415 Days
• Field of Search: 324/537, 324/548, 320/166, 320/167, 318/751, 318/794
• US Class Current: 324/548
• CPC Class Codes: B60K 6/20 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 2220/18 Reluctance machines
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: B60L 58/24 for controlling the temperature of batteries
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2050/146 Display means
• CPC Class Codes: B60W 2510/081 Speed
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2510/246 : Temperature
• CPC Class Codes: B60W 2510/248 : Age of storage means
• CPC Class Codes: B60W 2710/0644 : Engine speed
• CPC Class Codes: B60W 2710/081 : Speed
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: B60Y 2400/114 : Super-capacities
• CPC Class Codes: E02F 9/2075 : of the hybrid type for vehicles in general B60W20/00
• CPC Class Codes: E02F 9/2091 : Control of energy storage means for electrical energy, e.g. battery or capacitors energy recovery arrangements in hydraulic or pneumatic drives E02F9/2217
• CPC Class Codes: E02F 9/26 : Indicating devices E02F5/145 takes precedence
• CPC Class Codes: G01R 31/392 : Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H01G 11/08 : Structural combinations, e.g. assembly or connection, of hybrid or EDL capacitors with other electric components, at least one hybrid or EDL capacitor being the main component
• CPC Class Codes: H01G 11/14 : Arrangements or processes for adjusting or protecting hybrid or EDL capacitors emergency protective circuit arrangements specially adapted for capacitors, and effecting automatic switching in the event of an undesired change from normal working conditions H02H7/16; emergency protective circuit arrangements for limiting excess current or voltages without disconnection H02H9/00
• CPC Class Codes: H01G 4/008 : Selection of materials
• CPC Class Codes: H01G 9/048 : characterised by their structure H01G11/22 takes precedence
• CPC Class Codes: H01M 10/48 : Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 10/486 : for measuring temperature
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

The degradation of an electrical storage device 30 such as a capacitor can be determined by a system which is not an external device but is installed in hybrid construction equipment 1 in a state that the electrical storage device 30 such as a capacitor is mounted. To achieve this objective, it is at least checked that the working machine has stopped. Next, when it has been checked that the working machine has stopped, a degradation state determination time control mode is entered, a motor-generator is driven at the prescribed rotational speed and the prescribed torque, and the electrical storage device rises from the prescribed start charging voltage to the prescribed end charging voltage (Step 102). Next, the capacitance of the electrical storage device is calculated based on the values of the rotational speed and the torque of the motor-generator during the degradation state determination time control mode, the values of the start charging voltage and the end charging voltage of the electrical storage device, and the time needed for the electrical storage device to reach the end charging voltage form the start charging voltage. Next, by comparing the calculated capacitance of the electrical storage device and the reference capacitance, the degradation state of the electrical storage device is determined.

Claims

1. A method for determining a degradation state of an electrical storage device in hybrid construction equipment provided with an engine, a motor-generator, an electrical storage device, an electric power load, and a working machine driven by the electric power load, comprising:

a step of checking that at least the working machine has halted;

a step of shifting into a degradation state determination time control mode when it is checked that the working machine has halted, and increasing in the electrical storage device from a prescribed start charging voltage to a prescribed end charging voltage by driving the motor-generator at a prescribed rotational speed and with a prescribed torque;

a step of calculating a capacitance of the electrical storage device based on values of the rotational speed and the torque of the motor-generator during the degradation state determination time control mode, values of the start charging voltage and the end charging voltage of the electrical storage device, and a time required for the electrical storage device to reach the end charging voltage from the start charging voltage; and

a step of determining the degradation state of the electrical storage device by comparing the calculated capacitance of the electrical storage device with a reference capacitance.

2. The method for determining a degradation state of an electrical storage device in hybrid construction equipment according to claim 1, characterized in that

the capacitance of the electrical storage device is calculated after the capacitance is corrected by temperature of the electrical storage device during the degradation state determination time control mode.

3. The method for determining a degradation state of an electrical storage device in hybrid construction equipment according to claim 1, characterized in that

the charging operation to increase in the electrical storage device from the start charging voltage to the end charging voltage is performed a plurality of times during the degradation state determination time control mode;

and

the degradation state of the electrical storage device is determined by calculating an average capacitance by averaging capacities of the electrical storage device of respective charging operations, and by comparing the average capacitance with the reference capacitance.

4. The method for determining a degradation state of an electrical storage device in hybrid construction equipment according to claim 1, characterized by further comprising a step of displaying a result of determination of the degradation state of the electrical storage device.

5. A device for determining a degradation state of an electrical storage device in hybrid construction equipment provided with:

an engine;

a motor-generator having a drive shaft that is connected to an output shaft of the engine, and performs an electric power generating action and an electric motor action;

an electrical storage device that stores electric power when the motor-generator performs the electric power generating action, and supplies the electric power to an electric power load and the motor-generator;

the electric power load; and

a working machine driven by the electric power load, characterized in that

the device for determining a degradation state of an electrical storage device comprises;

a voltage value detecting unit that detects a charging voltage value in the electrical storage device; and

a control device that performs a control for determining the degradation state of the electrical storage device, wherein

the control device comprises;

a state managing unit that checks that at least the working machine has halted, and outputs a command to shift into a degradation state determination time control mode when it is checked that the working machine has halted;

a charge and discharge control unit that performs a shift into the degradation state determination time control mode when the command is given from the state managing unit, and gives a control command to the engine and the motor-generator so that the motor-generator is driven at a prescribed rotational speed and with a prescribed torque in order to increase in the electrical storage device from a start charging voltage to an end charging voltage while taking in a charging voltage value of the electrical storage device detected by the voltage value detecting unit;

a capacitance calculating unit that calculates a capacitance of the electrical storage device based on values of the rotational speed and the torque of the motor-generator during the degradation state determination time control mode, values of the start charging voltage and the end charging voltage of the electrical storage device, and a time required for the electrical storage device to reach the end charging voltage from the start charging voltage; and

a degradation determining unit that determines the degradation state of the electrical storage device by comparing the calculated capacitance of the electrical storage device with a reference capacitance.

6. The device for determining a degradation state of an electrical storage device in hybrid construction equipment according to claim 5, characterized by further comprising:

a temperature detecting unit that detects temperature of the electrical storage device, wherein

the capacitance calculating unit calculates the capacitance of the electrical storage device after the capacitance is corrected by the temperature of the electrical storage device during the degradation state determination time control mode.

7. The device for determining a degradation state of an electrical storage device in hybrid construction equipment according to claim 5, characterized in that

the charge and discharge control unit controls to perform a charging operation to increase in the electrical storage device from the start charging voltage to the end charging voltage a plurality of times,

the capacitance calculating unit calculates an average capacitance by averaging capacities of the electrical storage device of respective charging operations, and

the degradation determining unit determines the degradation state of the electrical storage device by comparing the average capacitance with the reference capacitance.

8. The device for determining a degradation state of an electrical storage device in hybrid construction equipment according to claim 5, characterized by further comprising

a display device, wherein

the control unit further comprises a state display unit for displaying a result of determination of the degradation state of the electrical storage device.

9. The device for determining a degradation state of an electrical storage device in hybrid construction equipment according to claim 5, characterized in that

the electric power load is an electric motor for driving the working machine.