DE-102016113926-B4 - Hybrid vehicle

Abstract

Hybrid vehicle (100) with a secondary battery (16), a drive mechanism (10) configured to generate a driving force by using electrical power from the secondary battery (16), an internal combustion engine (2), a power generation mechanism (6) configured to generate electrical power for charging the secondary battery (16) by using power output from the internal combustion engine (2), and an electronic control unit (25) which is configured, a) to calculate a control charge level based on an integrated current value, wherein the integrated current value is obtained by integrating an input current and an output current of the secondary battery (16), b) to control the operation of the power generation mechanism (6) such that the control charge state of the secondary battery (16) is kept close to a control setpoint (Sr) which is set as a predetermined control setpoint, c) to calculate an estimated actual state of charge of the secondary battery based on the integrated current value and a state of charge reduction magnitude due to self-discharge of the secondary battery (16), and, d) if the estimated actual state of charge has decreased to below a first lower limit state of charge, to raise the control setpoint.

Inventors

• Keiichi Minamiura

Assignees

• TOYOTA JIDOSHA KABUSHIKI KAISHA

Dates

Publication Date

20260513

Application Date

20160728

Priority Date

20150731

Claims (3)

1. Hybrid vehicle (100) comprising: a secondary battery (16), a drive mechanism (10) configured to generate tractive force by using electrical power from the secondary battery (16), an internal combustion engine (2), a power generation mechanism (6) configured to generate electrical power for charging the secondary battery (16) by using power output from the internal combustion engine (2), and an electronic control unit (25) configured: a) to calculate a control state of charge based on an integrated current value, the integrated current value being obtained by integrating an input current and an output current of the secondary battery (16), b) to control the operation of the power generation mechanism (6) such that the control state of charge of the secondary battery (16) is maintained close to a control setpoint (Sr) set as a predetermined control setpoint, c) to estimate an actual state of charge of the secondary battery based on the integrated current value and a to calculate the charge reduction magnitude due to self-discharge of the secondary battery (16), and, d) if the estimated actual charge has decreased to below a first lower limit charge, to increase the control setpoint.
2. Hybrid vehicle (100) after Claim 1 , wherein the electronic control unit (25) is configured, e) when the control state of charge has decreased to a second lower limit state of charge, to force the charging of the secondary battery (16) by operating the power generation mechanism (6), wherein the second lower limit state of charge is higher than the first lower limit state of charge, and, f) when the estimated actual state of charge has decreased to below the first lower limit state of charge, and the number of times the secondary battery (16) has been forcibly charged is less than a predetermined number, to prevent an increase in the control setpoint.
3. Hybrid vehicle (100) after Claim 1 or 2 , furthermore with an auxiliary load (45), wherein the electronic control unit (25) is configured, g) if the hybrid vehicle (100) has been left in a parking area for longer than a predetermined time and the electrical power consumed by the auxiliary load (45) is greater than or equal to a predetermined value, to increase the control setpoint.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention The disclosure relates to a hybrid vehicle and more specifically to a charging and discharging control system on a secondary battery attached to a hybrid vehicle while the hybrid vehicle is in motion. 2. Description of the state of the art A hybrid vehicle can charge a secondary battery mounted within the vehicle while driving by using power generation that accompanies the operation of a power engine. For this reason, as stated in the Japanese patent application publication... JP 2011 - 225 079 A ) describes how charging and discharging of a secondary battery is controlled by executing a forced discharge or forced charge control such that the state of charge (SOC) of the secondary battery is maintained within a predetermined range. In particular, the JP 2011 - 225 079 A A control to change a control center SOC in response to the number of times a forced load control is executed and the number of times a forced unload control is executed. The Japanese patent application publication JP 2003 - 047 108 A ) describes that when the charging memory effect of a secondary battery has been detected, the memory effect is eliminated while avoiding a reduction in vehicle performance and battery deterioration by increasing a target state of charge (SOC). However, in the JP 2011 - 225 079 A The described control system executes a normal charge and discharge control cycle before a forced charge, caused by the state of charge (SOC) approaching a lower control limit, is actually performed a certain number of times. For this reason, it is not possible to sufficiently prevent the occurrence of the memory effect, so there are concerns that the charge and discharge control at the secondary battery will change after the memory effect has occurred, as in the case of... JP 2003 - 047 108 A has occurred. The printed matter DE 43 37 020 C1 Disclosure reveals a method for monitoring the battery of a hybrid vehicle, wherein the state of charge of a battery is determined by balancing the amounts of charge supplied and withdrawn. The balancing process is periodically restarted from a reliable baseline value. The printed matter DE 10 2011 101 550 A1 A method and a device for charging a vehicle battery are disclosed. The frequency with which the battery's state of charge falls below a lower threshold is determined per unit of time. Charging is then carried out based on this frequency. The printed matter US 2013 / 0 124 029 A1 shows another method for controlling the state of charge of a vehicle battery, distinguishing between normal charging and extended charging when charging externally. The printed matter JP 2002 - 171 609 A discloses a charging/discharging control method in which a forced charging mode is carried out depending on the vehicle's idle time. The printed matter DE 10 2005 058 469 B4 Disclosure reveals a method for calculating the state of charge of a battery to prevent the memory effect. The calculation is performed using a reference capacity, which can be changed depending on the mode (normal state-of-charge maintenance mode, high state-of-charge range expansion mode, etc.). SUMMARY OF THE INVENTION It is an object of the present invention to provide a hybrid vehicle that controls the charging and discharging of a secondary battery in such a way as to prevent the occurrence of a memory effect. This problem is solved according to an embodiment of the disclosure by a hybrid vehicle as specified in claim 1. In the hybrid vehicle described above, if the estimated actual state of charge (SOC), which reflects the SOC reduction due to self-discharge of the secondary battery that cannot be replenished by integrating a current, has decreased, the SOC control setpoint is allowed to be raised using the power generation mechanism. Therefore, it is possible to prevent the occurrence of the charge memory effect of the secondary battery by preventing the actual SOC from remaining in a low SOC range due to the influence of self-discharge. The electronic control unit can be configured when the control SOC is The electronic control unit can be configured to prevent the secondary battery from being charged by operating the power generation mechanism when the estimated actual state of charge (SOC) has decreased to a second lower limit SOC, where the second lower limit SOC is higher than the first lower limit SOC. The electronic control unit can also be configured to prevent the control setpoint from increasing even if the estimated actual SOC has decreased below the first lower limit SOC, but if the number of times the secondary battery has been forcibly charged is less than a predetermined number. With this configuration, before a forced charging cycle is activated to prevent the control SOC from dropping below the second lower limit SOC (S1), an increase in the control SOC setpoint is prevented for a predetermined number of times, even if the estimated actual SOC has decreased to the lowe