Patent Publication Number: US-2022239141-A1

Title: Vehicle battery control system

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to Japanese Patent Application No. 2021-010225 filed on Jan. 26, 2021, which is incorporated herein by reference in its entirety including the specification, claims, drawings, and abstract. 
     TECHNICAL FIELD 
     The present disclosure relates to a battery control system for a vehicle in which a battery is located under an occupant seat. 
     BACKGROUND 
     A vehicle such as an electric vehicle is provided with a drive battery. For example, JP 2015-107728 A discloses an electric vehicle in which a battery is located under a rear seat. For such an electric vehicle, an output upper limit value and an input upper limit value of the battery are set according to a battery temperature by a battery control system, and thus, a cruising distance and traveling performance of the electric vehicle are constant as long as the battery temperature remains unchanged. 
     CITATION LIST 
     PATENT DOCUMENT 1: JP 2015-107728 A 
     For the above electric vehicle with the battery under the occupant seat, the output upper limit value and the input upper limit value of the battery may be increased to enhance the cruising distance and traveling performance. However, in this case, the occupant seat becomes warmer as the battery temperature increases, resulting in degradation in comfort for an occupant seated on the occupant seat. 
     SUMMARY 
     In light of the above, an object of the present disclosure is to provide a vehicle battery control system that can both enhance the cruising distance and traveling performance of a vehicle and provide comfort for the occupant. 
     A vehicle battery control system according to the present disclosure includes a battery located under an occupant seat, an occupant detection unit that detects whether an occupant is seated on the occupant seat, and a controller that sets an output upper limit value or an input upper limit value of the battery, and in this system, when the occupant detection unit detects no occupant on the occupant seat, the controller increases the output upper limit value or the input upper limit value of the battery and sets the resulting value as a setting, and when the occupant detection unit detects an occupant seated on the occupant seat, the controller decreases the output upper limit value or the input upper limit value of the battery and sets the resulting value as a setting. 
     In the vehicle battery control system according to the present disclosure, when an occupant seat other than the occupant seat under which the battery is located is intensively air conditioned, in some embodiments, the controller increases the output upper limit value or the input upper limit value of the battery and sets the resulting value as a setting. 
     In the vehicle battery control system according to the present disclosure, when the occupant seat under which the battery is located is intensively air conditioned, in some embodiments, the controller decreases the output upper limit value or the input upper limit value of the battery and sets the resulting value as a setting. 
     The vehicle battery control system according to the present disclosure further includes a battery temperature detection unit that detects a temperature of the battery, and when the temperature of the battery is lower than a predetermined temperature, in some embodiments, the controller increases the output upper limit value or the input upper limit value of the battery and sets the resulting value as a setting. 
     The vehicle battery control system according to the present disclosure further includes a battery temperature detection unit that detects a temperature of the battery, and when the temperature of the battery is higher than or equal to a predetermined temperature, in some embodiments, the controller decreases the output upper limit value or the input upper limit value of the battery and sets the resulting value as a setting. 
     With a vehicle battery control system according to the present disclosure, it is possible to both enhance a cruising distance and traveling performance of a vehicle and provide comfort for an occupant. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       An embodiment of the present disclosure will be described based on the following figures, wherein: 
         FIG. 1  is a schematic diagram showing a vehicle battery control system as an example of an embodiment; 
         FIG. 2  is a block diagram showing a configuration of a controller; 
         FIG. 3  is a graph indicating a correlation between battery temperature and input and output upper limit values of a battery; and 
         FIG. 4  is a flow chart indicating a control flow by the controller. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     An example of an embodiment of the present disclosure will be described in detail hereinafter. In the description below, specific shapes, materials, directions, numerical values, etc. are provided as illustrations for facilitating the understanding of the present disclosure, and can be appropriately changed according to applications, purposes, specifications, and the like. 
     With reference to  FIG. 1 , a vehicle battery control system  10  will be described as the example of the embodiment.  FIG. 1  is a schematic diagram showing the vehicle battery control system  10 . 
     The vehicle battery control system  10  is a system provided in a vehicle  11  in which a battery  14  is located under a rear seat  13 R, for changing an output upper limit value or an input upper limit value that is set in advance according to the presence of an occupant seated on the rear seat  13 R. With the vehicle battery control system  10 , it is possible to both enhance a cruising distance and traveling performance of the vehicle  11  and provide comfort for an occupant as described in detail below. 
     The vehicle  11  according to the present example is an electric vehicle that uses the charged battery  14  and runs on a motor, but this is not limiting. The vehicle may be a hybrid vehicle, for example. 
     The vehicle battery control system  10  has a plurality of occupant seats  13  which are provided in a vehicle interior  12  and on which occupants sit, the battery  14  located under the rear seat  13 R of the occupant seats  13 , an air conditioner  15  that air conditions the vehicle interior  12 , and a controller (Electronic controller, ECU)  20  that changes an output upper limit value or an input upper limit value of the battery  14 . 
     The controller  20  of the vehicle battery control system  10  includes an operation unit  16  that can perform setting of intensive air conditioning described below, an occupant sensor  17  serving as an occupant detection unit that detects whether an occupant is seated on the rear seat  13 R, and a battery temperature sensor  18  serving as a battery temperature detection unit that detects a temperature of the battery  14 . 
     The occupant seats  13  are seats which are provided in the vehicle interior  12  of the vehicle  11  and on which occupants sit. In the present example, the occupant seats  13  include two front seats  13 F arranged in the vehicle width direction on the front side of the vehicle interior and two rear seats  13 R arranged in the vehicle width direction on the rear side of the vehicle interior. 
     The battery  14  is a drive battery, and in some embodiments a lithium ion secondary battery is used as the battery  14 . As described above, the battery  14  is located under the rear seat  13 R of the occupant seats  13 . Although in the present example the battery  14  is located under the rear seat  13 R, this is not limiting, and the battery  14  may be located under the front seat  13 F. 
     The air conditioner  15  is an apparatus for air conditioning the vehicle interior  12 . The air conditioner  15  has a function of intensively air conditioning a particular occupant seat  13  (for example, the front seat  13 F or the rear seat  13 R). The operation unit  16  is provided in the vehicle interior  12  and is configured to enable setting of an occupant seat  13  which is to be intensively air conditioned by the air conditioner  15 . Information on intensive air conditioning set by the operation unit  16  is transmitted to the controller  20 . 
     The occupant sensor  17  is a sensor that is provided on the backside of a seat surface of the rear seat  13 R and detects whether an occupant is seated on the seat according to changes in resistance value of a strain gauge based on the body weight of the occupant on the rear seat  13 R. A detection signal generated by the occupant sensor  17  is transmitted to the controller  20 . 
     Although in the present example the occupant sensor  17  is employed as the occupant detection unit, this is not limiting. For example, the occupant detection unit may be configured to detect the entry and exit of an occupant with respect to the rear seat  13 R by using a rear door open/close sensor to detect whether the occupant is seated on the rear seat  13 R. The occupant detection unit may also be configured to detect buckling of a seat belt of the rear seat  13 R by using a seat belt buckle sensor of the rear seat  13 R to detect whether an occupant is seated on the rear seat  13 R. 
     The battery temperature sensor  18  is a sensor that is provided near the battery  14  and detects a temperature of the battery  14 . A detection signal generated by the battery temperature sensor  18  is transmitted to the controller  20 . 
     The controller  20  has a central processing unit (CPU) which includes a computation unit and a storage unit, such as a random-access memory (RAM), a read-only memory (ROM), and the like. The controller  20  performs signal processing according to a program stored in the ROM in advance while using a temporary storage function of the RAM. The controller  20  will be described in detail below. 
     The configuration of the controller  20  will be described with reference to  FIGS. 2  and  3 .  FIG. 2  is a block diagram showing a configuration of the controller  20 .  FIG. 3  is a graph indicating a correlation between temperature of the battery  14  and input and output upper limit values of the battery  14 . 
     The controller  20  is connected to the operation unit  16 , the occupant sensor  17 , the battery temperature sensor  18 , and the like and receives signals transmitted therefrom. The controller  20  is also connected to the battery  14  and the like and transmits signals thereto. 
     The controller  20  includes an occupant information acquisition unit  21  that acquires information as to whether an occupant is seated on the rear seat  13 R under which the battery  14  is located, an intensive air conditioning information acquisition unit  22  that acquires information on intensive air conditioning by the air conditioner  15 , a battery temperature acquisition unit  23  that acquires information on a temperature of the battery  14 , and an input/output upper limit value change unit  24  that changes an input upper limit value or an output upper limit value of the battery  14 . 
     When the operation unit  16  sets an occupant seat  13  to be intensively air conditioned, the intensive air conditioning information acquisition unit  22  functions to acquire information on that occupant seat  13  set to be intensively air conditioned. When, for example, the intensive air conditioning information acquisition unit  22  acquires information indicating that the front seat  13 F is set to be intensively air conditioned, it is highly likely that no occupant is seated on the rear seat  13 R. Also, when, for example, the intensive air conditioning information acquisition unit  22  acquires information indicating that the rear seat  13 R is set to be intensively air conditioned, it is highly likely that an occupant is seated on the rear seat  13 R and seeks comfort. 
     When no occupant is seated on the rear seat  13 R, the input/output upper limit value change unit  24  functions to increase the input upper limit value or the output upper limit value of the battery  14  to change the setting. When an occupant is seated on the rear seat  13 R, the input/output upper limit value change unit  24  functions to decrease the input upper limit value or the output upper limit value of the battery  14  to change the setting. 
     Here, the input upper limit value is an upper limit value of an input to the battery  14  and includes an upper limit value obtained when power is input to the battery  14  by a regenerative brake and an upper limit value obtained when power is input to the battery  14  by an external charging facility. In addition, the output upper limit value is an upper limit value of an output of the battery  14  obtained when the vehicle  11  is running and includes an upper limit value obtained when power is output from the battery  14  to a drive motor driven according to the accelerator position. 
     With the input/output upper limit value change unit  24 , it is possible to both enhance a cruising distance and traveling performance of the vehicle  11  and provide comfort for an occupant. More specifically, when no occupant is seated on the rear seat  13 R, the input/output upper limit value change unit  24  can increase the input upper limit value or output upper limit value of the battery  14  to change the setting, thereby enhancing the cruising distance and traveling performance of the vehicle  11 . On the contrary, when an occupant is seated on the rear seat  13 R, it can decrease the input upper limit value or output upper limit value of the battery  14  to change the setting, thereby improving the comfort of the rear seat  13 R. 
     The input/output upper limit value change unit  24  may also increase the input upper limit value or the output upper limit value of the battery  14  to change the setting when the front seat  13 F is set to be intensively air conditioned. This also makes it possible to prevent a reduction in cruising distance and traveling performance of the vehicle  11  which occurs when the occupant sensor  17  malfunctions; that is, when the occupant sensor  17  detects seat occupation erroneously despite no occupant on the rear seat  13 R. 
     The input/output upper limit value change unit  24  may also decrease the input upper limit value or the output upper limit value of the battery  14  to change the setting when the rear seat  13 R is set to be intensively air conditioned. Thus, when an occupant seated on the rear seat  13 R is seeking comfort, it is possible to decrease the input upper limit value or output upper limit value of the battery  14  to change the setting. 
     The input/output upper limit value change unit  24  may also increase the input upper limit value or the output upper limit value of the battery  14  to change the setting when a temperature of the battery  14  is lower than a predetermined temperature (for example, 40° C.). This makes it possible to enhance the safety efficiency of the battery  14  without increasing the battery temperature more than necessary. 
     The input/output upper limit value change unit  24  may also decrease the input upper limit value or the output upper limit value of the battery  14  to change the setting when a temperature of the battery  14  is higher than or equal to the predetermined temperature (for example, 40° C.). This makes it possible to prevent a reduction in cruising distance and traveling performance of the vehicle  11  more than necessary. 
     As shown in  FIG. 3 , the input upper limit value and output upper limit value of the battery  14  are set individually according to a temperature of the battery  14 . More specifically, the input/output upper limit value change unit  24  functions to change the settings so as to increase the input upper limit value or the output upper limit value for a normal case (solid lines in  FIG. 3 ) to the input upper limit value or the output upper limit value for the case where there is no occupant (broken lines in  FIG. 3 ). The input/output upper limit value change unit  24  also functions to change the settings so as to decrease the input upper value or the output upper limit value for the normal case to the input upper limit value or the output upper limit value for the case where there is an occupant (long dashed short dashed lines in  FIG. 3 ). 
     A control flow by the controller  20  will be described with reference to  FIG. 4 . 
     As shown in  FIG. 4 , in step S 11 , information as to whether an occupant is seated on the rear seat  13 R is acquired by the occupant information acquisition unit  21 . In step S 12 , the intensive air conditioning information acquisition unit  22  acquires information on intensive air conditioning set by the operation unit  16 . In step S 13 , the battery temperature acquisition unit  23  acquires a temperature of the battery  14  detected by the battery temperature sensor  18 . 
     In step S 14 , a decision is made based on the information as to whether the occupant is seated on the rear seat  13 R acquired in step S 11 . When the occupant is seated on the rear seat  13 R, the processing proceeds to step S 15 , while when no occupant is seated on the rear seat  13 R, the processing proceeds to step S 18 . 
     In step S 15 , a decision is made based on the information on intensive air conditioning acquired in step S 12 . When the rear seat  13 R is set to be intensively air conditioned, the processing proceeds to step S 16 . In step S 16 , a decision is made based on the information on the temperature of the battery  14  acquired in step S 13 . When the temperature of the battery  14  is higher than or equal to a predetermined temperature (for example 40° C.), the processing proceeds to step S 17 . 
     In step S 17 , the input/output upper limit value change unit  24  decreases the input upper limit value or output upper limit value of the battery  14  to change the setting, thereby improving the comfort of the rear seat  13 R. The setting is changed such that, in the graph of  FIG. 3 , the input upper limit value or the output upper limit value for the normal case (solid lines in  FIG. 3 ) is decreased to the input upper limit value or the output upper limit value for the case where there is an occupant (long dashed short dashed lines in  FIG. 3 ). Step S 15  or step S 16  may be omitted, and the processing may proceed directly from step S 14  to step S 17 . 
     Meanwhile, in step S 18 , a decision is made based on the information on intensive air conditioning acquired in step S 12 . When the front seat  13 F is set to be intensively air conditioned, the processing proceeds to step S 19 . In step S 19 , a decision is made based on the information on the temperature of the battery  14  acquired in step S 13 . When the temperature of the battery  14  is lower than the predetermined temperature (for example 40° C.), the processing proceeds to step S 20 . 
     In step S 20 , the input/output upper limit value change unit  24  increases the input upper limit value or output upper limit value of the battery  14  to change the setting, thereby enhancing the cruising distance and traveling performance of the vehicle  11 . The setting is also changed such that, in the graph of  FIG. 3 , the input upper limit value or the output upper limit value for the normal case (solid lines in  FIG. 3 ) is increased to the input upper limit value or the output upper limit value for the case where there is no occupant (broken lines in  FIG. 3 ). Step S 18  or step S 19  may be omitted, and the processing may proceed directly from step S 14  to step S 20 . 
     The present disclosure is not limited to the above embodiment and its variations, and, as a matter of course, various modifications and substitutions can be made without departing from the scope of the claims herein.