Battery Resistance Measurement Device, Vehicle, and Battery Resistance Measurement Method

Abstract

The present invention relates to a battery resistance measurement device, a vehicle, and a battery resistance measurement method. The battery resistance measurement device (510) measures the resistance of a battery to be measured, and includes a determination unit (511) and a measurement unit (512). The determination unit is configured to determine whether the battery to be measured has switched from a charging state to a discharging state in which power greater than the supplied power is output while receiving power supply based on whether a predetermined condition is satisfied. The measurement unit is configured to start measuring the resistance of the battery to be measured at a timing when the determination unit determines that the battery to be measured has switched from the charging state to the above-described discharging state.

Description

Technical Field

[0001] The present disclosure relates to a battery resistance measurement device, a vehicle, and a battery resistance measurement method. Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2004-031170 discloses a method for calculating the internal resistance of a secondary battery mounted on a vehicle during vehicle travel. In this method, during vehicle travel in which charging and discharging of the secondary battery are frequently performed, the polarization state (degree of influence of polarization), voltage, and current of the secondary battery are repeatedly obtained, data (voltage and current) with a small degree of influence of polarization are selected, and the internal resistance of the secondary battery is calculated using only the data (voltage and current) with a small degree of influence of polarization. Summary of the Invention

[0003] However, in the battery resistance measurement method described in Japanese Unexamined Patent Application Publication No. 2004-031170, in order to select data (voltage and current) with a small degree of influence of polarization, it is necessary to measure the polarization state of the secondary battery with high accuracy. And, in order to measure the polarization state of the secondary battery with high accuracy, the arithmetic processing load increases.

[0004] The present disclosure has been completed to solve the above problems, and an object thereof is to provide a battery resistance measurement device, a vehicle, and a battery resistance measurement method that can simply and accurately measure the resistance of a battery.

[0005] The battery resistance measurement device according to the first aspect of the present disclosure is a battery resistance measurement device that measures the resistance of a battery to be measured, and includes a determination unit and a measurement unit as shown below.

[0006] The determination unit is configured to determine whether the battery to be measured has switched from a charging state to a discharging state in which, while receiving power supply, it outputs power greater than the supplied power based on whether a predetermined condition is satisfied. The measurement unit is configured to start measuring the resistance of the battery to be measured at the timing when the determination unit determines that the battery to be measured has switched from the charging state to the above-described discharging state.

[0007] Hereinafter, the discharging state of a battery that outputs power greater than the supplied power while receiving power supply is also referred to as the "discharging state (while receiving power)". Sometimes the timing at which it is determined that the battery has switched from the charging state to the discharging state (while receiving power) is referred to as the "charging and discharging switching timing".

[0008] At the charge-discharge switching timing of the target battery, the polarization generated during the charging of the target battery is canceled out by the discharge of the target battery and becomes smaller. In addition, at the charge-discharge switching timing of the target battery, the power supplied to the target battery and the power output from the target battery are substantially equal. Therefore, by starting the measurement of the resistance of the target battery at the charge-discharge switching timing, it is easy to measure the resistance of the target battery during a period when the battery current is small. During a period when the battery current is small, the influence of polarization is small, and the relationship between the battery voltage and the battery current is close to linear. By measuring the resistance of the target battery during such a period, it is easy to measure the resistance of the target battery with high accuracy. On the other hand, when the battery current is large, the relationship between the battery voltage and the battery current easily becomes non-linear, so the measurement accuracy of the battery resistance easily decreases.

[0009] As described above, according to the above battery resistance measurement device, the resistance of the target battery can be measured during a period when the influence of polarization is small. Therefore, even if the measurement accuracy of the polarization state of the battery is low, or even if the measurement of the polarization state of the battery itself is not performed, the resistance of the battery can be measured with sufficient accuracy. In this way, the above battery resistance measurement device can simply and accurately measure the resistance of the battery.

[0010] The target battery may be a battery pack including a plurality of parallel-connected single battery blocks. Each of the plurality of parallel-connected single battery blocks may include a plurality of secondary batteries connected in parallel. The plurality of parallel-connected single battery blocks may be connected in series with each other. The measurement unit may be configured to measure the resistance of at least one parallel-connected single battery block included in the battery pack. The above battery resistance measurement device may further include a diagnosis unit that uses the resistance of any one of the parallel-connected single battery blocks included in the battery pack as the target block to diagnose the presence or absence of a disconnection of the target block.

[0011] In the above target battery, sometimes due to disconnection (including fuse melting and fastening loosening), the electrical connection is disconnected in a part of the parallel-connected single battery block, and the secondary battery is detached from the parallel-connected single battery block. In the parallel-connected single battery block, if at least one of the plurality of secondary batteries connected in parallel is detached, the resistance of the parallel-connected single battery block becomes larger. Therefore, the above diagnosis unit can accurately diagnose the presence or absence of a disconnection of the target block based on the resistance of the target block.

[0012] The above diagnosis unit may be configured to diagnose the presence or absence of a disconnection of the target block using the degree of deviation between the resistance of the target block and the resistance of the parallel-connected single battery block adjacent to the target block in the battery pack.

[0013] Hereinafter, the parallel-connected single battery block adjacent to the target block in the battery pack will also be referred to as an "adjacent block".

[0014] The above-described diagnostic unit diagnoses the presence or absence of a disconnection in the target block using the degree of deviation between the resistance of the target block and the resistance of an adjacent block (hereinafter also referred to as "resistance deviation"). When the resistance deviation is large, it can be considered that a disconnection has occurred in the parallel single battery block with a large resistance among the target block and the adjacent blocks. As a parameter representing the degree of deviation, for example, a difference or a ratio can be adopted. The larger the difference (absolute value) between the two, the greater the degree of deviation between the two. The closer the ratio of the two is to 1, the smaller the degree of deviation between the two. The resistance deviation can be the ratio of the resistance of the target block to the resistance of the adjacent block.

[0015] The above-described diagnostic unit can determine that a disconnection has occurred in the target block (no disconnection in the adjacent block) when the resistance deviation is greater than a predetermined level and the resistance of the target block is greater than the resistance of the adjacent block. The above-described diagnostic unit can determine that a disconnection has occurred in the adjacent block (no disconnection in the target block) when the resistance deviation is greater than a predetermined level and the resistance of the adjacent block is greater than the resistance of the target block.

[0016] The above-described measurement unit can be configured to measure the resistance of each parallel single battery block included in the battery pack. The above-described diagnostic unit can be configured to: sequentially change the target block and use the resistance of each parallel single battery block measured by the measurement unit to diagnose the presence or absence of a disconnection in the battery pack. With such a configuration, the presence or absence of a disconnection in the battery pack can be accurately diagnosed.

[0017] The above-described measurement unit can be configured to: measure the current and voltage during discharge of the target battery and use the measured current and voltage to measure the resistance of the target battery.

[0018] By starting the measurement of the resistance of the target battery at the charge-discharge switching timing, the relationship between the current and voltage during discharge of the target battery measured by the above-described measurement unit is close to linear. Therefore, the above-described measurement unit can easily measure the resistance of the target battery (e.g., the internal resistance of a secondary battery) with high accuracy based on the measured current and voltage.

[0019] The vehicle according to the second aspect of the present disclosure includes: the battery resistance measurement device according to any one of the above; a target battery; an auxiliary machine that receives power supply from the target battery; and a control device that switches between multiple control modes. The multiple control modes include: a prohibition mode that prohibits driving the auxiliary machine using the power output from the target battery when the target battery is receiving power supply from outside the vehicle; and a permission mode that permits driving the auxiliary machine using the power output from the target battery when the target battery is receiving power supply from outside the vehicle. The above-described predetermined conditions in the battery resistance measurement device include: the control device is executing the permission mode (hereinafter also referred to as "requirement A"); and the auxiliary machine is driven after charging of the target battery is started using the power supplied from outside the vehicle (hereinafter also referred to as "requirement B").

[0020] In the above vehicle, the control device can switch between a prohibited mode and a permitted mode. By prohibiting the use of a predetermined auxiliary machine during the charging of the target battery using the prohibited mode, the control device can accelerate the progress of charging the target battery. In addition, by permitting the use of a predetermined auxiliary machine using the permitted mode, the control device can improve user convenience. The above control device can be configured to switch between the prohibited mode and the permitted mode based on an input from the user.

[0021] In the above vehicle, a predetermined auxiliary machine permitted to be driven in the permitted mode is driven by the power output from the target battery. The predetermined auxiliary machine may include auxiliary machines that consume a large amount of power (for example, an air conditioning device or various heaters). When the target battery is receiving power supply from outside the vehicle, if an auxiliary machine that consumes a large amount of power is driven, it is easy to output power from the target battery that is greater than the power supplied to the target battery. Therefore, when both requirement A and requirement B are satisfied, the target battery is likely to switch from the charging state to the discharging state (while receiving power). Thus, in the above vehicle, the aforementioned determination unit can easily and accurately determine whether the target battery has switched from the charging state to the discharging state (while receiving power) based on whether a predetermined condition is satisfied.

[0022] In the above vehicle, each of requirement A and requirement B is a requirement necessary for the above predetermined condition to be satisfied. When at least one of requirement A and requirement B is not satisfied, the above predetermined condition is not satisfied. The above predetermined condition may be satisfied when both requirement A and requirement B are satisfied, or may be satisfied when other requirements (additional requirements) are satisfied in addition to requirement A and requirement B. The additional requirements relative to requirement A and requirement B can be set arbitrarily.

[0023] In the above vehicle, the battery resistance measurement device and the control device may be two separate units, or may be a shared unit (i.e., a single unit having the functions of both the battery resistance measurement device and the control device).

[0024] The above auxiliary machine that receives power supply from the target battery may be an air conditioning device that performs air conditioning inside the vehicle.

[0025] Generally speaking, the air conditioning device consumes a large amount of power. Therefore, when the target battery is receiving power supply from outside the vehicle, if the air conditioning device is driven by the power supplied from the target battery, it is easy to output power from the target battery that is greater than the power supplied to the target battery.

[0026] The target battery mounted on the vehicle can store power for driving in the vehicle. The above vehicle may be an electric vehicle. An electric vehicle is a vehicle configured to run using the power supplied from a battery (for example, the target battery) mounted on the vehicle. In electric vehicles, in addition to BEV (battery electric vehicle) and PHEV (plug-in hybrid vehicle), it also includes FCEV (fuel cell vehicle), range extender EV, etc.

[0027] The above control device can be configured to set an input limit value according to the temperature of the target battery, and control the input current of the target battery in such a way that the input power of the target battery does not exceed the input limit value. The above control device can be configured to set the input limit value in such a way that the input limit value when the temperature of the target battery is lower than a predetermined temperature is lower than the input limit value when the temperature of the target battery is higher than the predetermined temperature. The above-mentioned predetermined condition in the battery resistance measurement device may further include that the temperature of the target battery is lower than the predetermined temperature (hereinafter, also referred to as "requirement C").

[0028] In the above vehicle, the control device controls the input current of the target battery in such a way that the input power of the target battery does not exceed the input limit value. The input limit value can be set to suppress the deterioration of the target battery. In the above vehicle, the input limit value is set according to the temperature of the target battery. When the temperature of the target battery is lower than the predetermined temperature, the input limit value is low. Since the power supplied to the target battery is limited by the input limit value, if the auxiliary machine is driven when the input limit value is low, the power output from the target battery is likely to be greater than the power supplied to the target battery. Therefore, when all of requirements A to C are satisfied, the target battery is likely to switch from the charging state to the discharging state (while receiving power). In the above vehicle, the aforementioned determination unit can easily and accurately determine whether the target battery has switched from the charging state to the discharging state (while receiving power) based on whether the predetermined condition is satisfied.

[0029] In the above vehicle, each of requirements A to C is a requirement necessary for the above-mentioned predetermined condition to be satisfied. When at least one of requirements A to C is not satisfied, the above-mentioned predetermined condition is not satisfied. The above-mentioned predetermined condition may be satisfied when requirements A to C are satisfied, or may be satisfied when other requirements (additional requirements) are satisfied in addition to requirements A to C. The additional requirements for requirements A to C can be set arbitrarily.

[0030] The above target battery may include a lithium-ion secondary battery. The control device can be configured to set the input limit value in such a way that lithium metal does not precipitate on the negative electrode of the lithium-ion secondary battery.

[0031] In the above vehicle, the precipitation of lithium metal on the negative electrode of the lithium-ion secondary battery can be suppressed by the input limit value.

[0032] The battery resistance measurement method according to the third aspect of the present disclosure is a battery resistance measurement method for measuring the resistance of a target battery, including: determining whether the target battery has switched from the charging state to the discharging state of receiving power supply and outputting power greater than the supplied power based on whether a predetermined condition is satisfied; and starting the measurement of the resistance of the target battery when it is determined that the target battery has switched from the charging state to the above-mentioned discharging state.

[0033] According to the above battery resistance measurement method, similar to the aforementioned battery resistance measurement device, the resistance of the battery can be measured simply and accurately.

[0034] The above and other objects, features, aspects, and advantages of the present invention will become apparent from the following detailed description of the present invention understood in association with the accompanying drawings. Description of the Drawings

[0035] Figure 1 It is a diagram showing a schematic structure of a vehicle according to an embodiment of the present disclosure.

[0036] Figure 2 It shows Figure 1 a diagram showing the structures of the battery pack and the monitoring module included in the storage battery shown.

[0037] Figure 3 It shows Figure 1 a diagram showing the detailed structure of the vehicle control device shown.

[0038] Figure 4 It is a diagram showing Figure 2 a mapping showing the relationship between the temperature of the battery pack shown and the input limit value (Win).

[0039] Figure 5 It is a flowchart showing the process related to the switching of the control mode executed by the vehicle control device shown. Figure 1

[0040] Figure 6 It is a diagram showing Figure 5 an example of a selection screen used in the process shown.

[0041] Figure 7 It is a diagram showing an example of the current of the battery pack when the air conditioning device is driven during external charging of the battery pack in a low temperature state in the allow mode.

[0042] Figure 8 It is a diagram showing an example of the current of the battery pack during external charging in the prohibit mode.

[0043] Figure 9 It is a diagram showing an example of the current of the battery pack when the air conditioning device is driven during external charging of the battery pack in a high temperature state in the allow mode.

[0044] Figure 10 It is a diagram showing Figure 1 an example of the change in the current of the battery pack when the measurement start condition is satisfied during external charging of the battery pack shown.

[0045] Figure 11 ​It is a graph showing the relationship between the measured current and voltage of a battery pack according to an embodiment of the present disclosure.

[0046] Figure 12 It is a diagram showing an example of the current when a disconnection occurs in a parallel single cell block during charging.

[0047] Figure 13 It is a flowchart showing a method for measuring the battery resistance according to an embodiment of the present disclosure.

[0048] Figure 14 It shows Figure 13 A flowchart showing the details of the battery diagnosis process shown.

[0049] Figure 15 It shows Figure 13 A diagram showing a modified example of the process shown. Detailed Embodiments

[0050] While referring to the attached Figure 1 The embodiments of the present disclosure will be described in detail. In the figures, the same or corresponding parts are denoted by the same reference numerals, and their description will not be repeated. In addition, each step in the flowchart is abbreviated as "S". In addition, Electronic Control Unit (electronic control unit) is sometimes denoted as "ECU". In addition, Electric Vehicle Supply Equipment (electric vehicle supply equipment) is sometimes denoted as "EVSE".

[0051] Figure 1 It is a diagram showing a schematic structure of a vehicle according to this embodiment. Referring to Figure 1 , the vehicle 50 includes a storage battery 300 that stores power for traveling and an ECU 500 that controls charging and discharging of the storage battery 300. The vehicle 50 can be an electric vehicle (BEV) that can travel only using the power stored in the storage battery 300, or a plug-in hybrid vehicle (PHEV) that can travel using both the power stored in the storage battery 300 and the output of an engine (not shown).

[0052] In this embodiment, the storage battery 300 includes a battery pack 130. The battery pack 130 is configured by electrically connecting a plurality of secondary batteries (hereinafter, also referred to as "single cells") to each other. In this embodiment, lithium-ion secondary batteries are used as single cells. However, the single cell can also be a secondary battery other than a lithium-ion secondary battery (for example, a nickel-metal hydride battery). The single cell can be a liquid-based secondary battery or an all-solid-state secondary battery. The battery pack 130 is an example of the "target battery" of the present disclosure. The specific structure of the battery pack 130 will be described later (refer to Figure 2 ).

[0053] The storage battery 300 further includes a monitoring module 140 that monitors the state of the battery pack 130. The monitoring module 140 includes a battery sensor that detects the state of the battery pack 130 and a signal processing circuit that processes the output signal of the battery sensor, and outputs the sensor signal processed by the signal processing circuit to the ECU 500. In this embodiment, a voltage sensor, a current sensor, and a temperature sensor that detect the voltage, current, and temperature of the battery pack 130 are used as the above-mentioned battery sensors. As the signal processing circuit, for example, a general-purpose IC (integrated circuit) can be used. The ECU 500 can obtain the state of the battery pack 130 (for example, temperature, current, voltage, SOC (State Of Charge: charge state), and internal resistance) based on the output of the monitoring module 140. The specific structure of the monitoring module 140 will be described later (refer to Figure 2 and Figure 3 ).

[0054] The vehicle 50 is provided with an access port 110 for contact charging and a DC charger 120. The access port 110 and the DC charger 120 correspond to the power supply method of the EVSE 40. In this embodiment, as the EVSE 40, a DC power supply device that provides DC power is adopted. The EVSE 40 may be a fast charger. The EVSE 40 is provided with a charging cable 41. The charging cable 41 is connected to the main body of the EVSE 40. The charging cable 41 may be always connected to the main body of the EVSE 40, or may be detachable from the main body of the EVSE 40. The charging cable 41 has a connector 42 at the tip and includes a power line inside. The EVSE 40 receives power supply from the power source PS, and outputs DC power to the connector 42. The power source PS may be, for example, a power grid provided by a power operator such as an electric power company. The power source PS may also supply AC power to the EVSE 40. The EVSE 40 may also convert the AC power into DC power and then output the DC power to the connector 42.

[0055] The access port 110 is configured to be able to connect to the connector 42 of the charging cable 41. The DC charger 120 is located between the access port 110 and the storage battery 300 and includes a circuit corresponding to the DC power supply device. The DC charger 120 includes, for example, a filter circuit and a charging relay. The charging relay is configured to switch the connection / cutoff of the power path from the access port 110 to the storage battery 300. The access port 110 is configured to receive power supplied from the outside of the vehicle 50 and output the power to the DC charger 120. The DC charger 120 is configured to convert the power received by the access port 110 into power suitable for charging the storage battery 300 and output the converted power to the storage battery 300.

[0056] The connector 42 of the charging cable 41 connected to the main body of the EVSE 40 is connected (inserted) to the inlet 110 of the parked vehicle 50, and the vehicle 50 becomes in a rechargeable state (i.e., a state in which power supply can be received from the EVSE 40). In the rechargeable vehicle 50, external charging can be performed (i.e., the battery 300 is charged using the power supplied from the EVSE 40). When external charging is being performed, the charging relay is set to the closed state (connected state), and when external charging is not being performed, the charging relay is set to the open state (cut-off state).

[0057] In addition, Figure 1 only the inlet 110 and the DC charger 120 corresponding to the power supply method of the EVSE 40 are shown, but the vehicle 50 may also be provided with a plurality of inlets and chargers in a manner capable of corresponding to a plurality of power supply methods (e.g., AC method and DC method).

[0058] The ECU 500 is configured to include a processor 501, a RAM (Random Access Memory) 502, a storage device 503, and a timer 504. The ECU 500 is, for example, a microcomputer. As the processor 501, a CPU (Central Processing Unit), for example, can be adopted. The RAM 502 functions as a working memory for temporarily storing data processed by the processor 501. The storage device 503 is configured to be able to save the stored information. The storage device 503 includes, for example, a ROM (Read Only Memory) and a rewritable non-volatile memory. In the storage device 503, in addition to programs, information used by the programs (e.g., maps, mathematical formulas, and various parameters) is also stored. In this embodiment, various controls in the ECU 500 are executed by the processor 501 executing the programs stored in the storage device 503. However, various controls in the ECU 500 are not limited to being executed based on software, and can also be executed using dedicated hardware (electronic circuits). In addition, the number of processors included in the ECU 500 is arbitrary, and a processor may be prepared for each predetermined control.

[0059] The timer 504 is configured to notify the processor 501 of the arrival of the set time. When the time set for the timer 504 is reached, a signal notifying this meaning is sent from the timer 504 to the processor 501. In this embodiment, a timer circuit is adopted as the timer 504. However, the timer 504 may also be implemented by software instead of hardware (timer circuit). In addition, the ECU 500 can obtain the current time using a real-time clock (RTC) circuit (not shown) built in the ECU 500.

[0060] The vehicle 50 also includes a driving unit 150, an input device 160, a notification device 170, and drive wheels W. In Figure 1 only one drive wheel W is shown, but the vehicle 50 includes four wheels (including the drive wheels W). However, the number of wheels of the vehicle 50 is arbitrary and may also be three or more than five. In addition, the drive mode of the vehicle 50 is also arbitrary and may be any one of front-wheel drive, rear-wheel drive, and four-wheel drive.

[0061] The driving unit 150 includes a PCU (Power Control Unit) 151 and an MG (Motor Generator) 152 and is configured to use the electric power stored in the battery pack 130 to drive the vehicle 50. The PCU 151 is configured to include, for example, an inverter, a converter, and a relay (hereinafter referred to as "SMR (System Main Relay)") (none of which are shown). The PCU 151 is controlled by the ECU 500. The MG 152 is, for example, a three-phase AC motor generator. The MG 152 is configured to be driven by the PCU 151 to rotate the drive wheels W. The PCU 151 uses the electric power supplied from the battery pack 130 to drive the MG 152. In addition, the MG 152 is configured to perform regenerative power generation and supply the generated electric power to the battery pack 130. The SMR is configured to switch the connection / cutoff of the power path from the battery pack 130 to the MG 152. The SMR is set to a closed state (connected state) during the driving of the vehicle 50.

[0062] The input device 160 is a device that receives input from the user. The input device 160 is operated by the user and outputs a signal corresponding to the user's operation to the ECU 500. The communication method can be wired or wireless. Examples of the input device 160 include various switches, various indicating devices, keyboards, and touch panels. The input device 160 can also be an operation unit of an automotive navigation system. The input device 160 can also be a smart speaker that receives voice input.

[0063] The notification device 170 is configured to perform a predetermined notification process to the user (for example, an occupant of the vehicle 50) when a request is generated from the ECU 500. The notification device 170 may include at least one of a display device (for example, a touch panel display), a speaker, and a lamp (for example, a MIL (Malfunction Indicator Lamp)). The notification device 170 can also be an instrument panel, a head-up display, or an automotive navigation system.

[0064] The vehicle 50 also includes a DC / DC converter 310 and an air conditioner 320. The air conditioner 320 is configured to condition the air in the passenger compartment of the vehicle 50. The air conditioner 320 includes an electric compressor (not shown) for air conditioning. A user of the vehicle 50 can operate the input device 160 to cause the air conditioner 320 to perform heating or cooling of the passenger compartment. The DC / DC converter 310 is located between the battery 300 and the air conditioner 320 and is configured to cut off or transform the DC power supplied from the battery 300 to the air conditioner 320. The DC / DC converter 310 is controlled by the ECU 500. In the control of supplying the power of the battery 300 to the air conditioner 320, the ECU 500 connects the power supply path from the battery 300 to the air conditioner 320. And, the DC power output from the battery 300 is transformed into a predetermined DC power by the DC / DC converter 310 and supplied to the air conditioner 320.

[0065] The ECU 500 is configured to switch between multiple control modes. The multiple control modes include a normal mode and a my room mode. The normal mode is a control mode that prohibits using the power output from the battery pack 130 to drive a predetermined auxiliary machine (hereinafter referred to as "target auxiliary machine") when the battery pack 130 is receiving power supply from the DC charger 120. The my room mode is a control mode that allows using the power output from the battery pack 130 to drive the target auxiliary machine when the battery pack 130 is receiving power supply from the DC charger 120. In this embodiment, the target auxiliary machine is the air conditioner 320. An auxiliary machine of the vehicle 50 is a load that consumes power in the vehicle 50 other than electric driving. In the vehicle 50, each of the ECU 500, the notification device 170, and the air conditioner 320 corresponds to an auxiliary machine. Each of the ECU 500 and the notification device 170 receives power supply from an auxiliary machine battery (not shown). On the other hand, the MG152 (traveling motor) that generates power for electric driving does not correspond to an auxiliary machine. The normal mode and the my room mode respectively correspond to an example of the "prohibited mode" and the "permitted mode" of the present disclosure. The air conditioner 320 corresponds to an example of the "auxiliary machine" of the present disclosure.

[0066] The ECU 500 switches between the normal mode and the my room mode according to an input from a user of the vehicle 50. The user can instruct the ECU 500 to switch the control mode via the input device 160. When performing external charging of the battery pack 130, power is supplied from the EVSE 40 (outside the vehicle) to the DC charger 120 through the access port 110, and the DC charger 120 outputs this power to the battery pack 130. When the battery pack 130 is receiving power supply from the DC charger 120, in principle, the ECU 500 executes the normal mode and prohibits driving the air conditioner 320 using the power output from the battery pack 130. However, when the user instructs the ECU 500 to execute the my room mode, the ECU 500 executes the my room mode instead of the normal mode. Thereby, it is permitted to drive the air conditioner 320 using the power output from the battery pack 130. In the normal mode, during external charging of the battery pack 130, the power supply path from the storage battery 300 to the air conditioner 320 is cut off by the DC / DC converter 310. On the other hand, in the my room mode, power from the storage battery 300 is also supplied to the air conditioner 320 during external charging of the battery pack 130.

[0067] Figure 2 FIG. is a diagram showing the structures of the battery pack 130 and the monitoring module 140 included in the storage battery 300 respectively. Together with Figure 1 refer to Figure 2 , the battery pack 130 includes N single cell stacks (i.e., single cell stacks 200-1 to 200-N). N can be 5 or more, or can be 30 or more. In this embodiment, N is set to 10. The monitoring module 140 includes N voltage detection circuits (i.e., voltage detection circuits 141-1 to 141-N), one current detection circuit 142, and one temperature detection circuit 143.

[0068] The current detection circuit 142 is equipped with a current sensor IB that detects the current flowing through the single cell stacks 200-1 to 200-N. The current detection circuit 142 is configured to process the output signal of the current sensor IB. The temperature detection circuit 143 is equipped with a temperature sensor TB that detects the temperature of the battery pack 130. The temperature detection circuit 143 is configured to process the output signal of the temperature sensor TB. In this embodiment, the number of each of the current sensor IB and the temperature sensor TB included in the monitoring module 140 is one. However, it is not limited thereto, and the number of the current sensor IB and the temperature sensor TB can be appropriately changed. For example, the temperature sensor TB can also be provided for each single cell stack, each parallel single cell block, or each single cell.

[0069] The voltage detection circuits 141-1 to 141-N are respectively provided in the single battery stacks 200-1 to 200-N. Hereinafter, unless otherwise distinguished, each of the single battery stacks 200-1 to 200-N is referred to as "single battery stack 200", and each of the voltage detection circuits 141-1 to 141-N is referred to as "voltage detection circuit 141". Hereinafter, the structures of the single battery stack 200 and the voltage detection circuit 141 will be described respectively.

[0070] In this embodiment, each of the single battery stacks 200-1 to 200-N has the same structure (i.e., Figure 2 the detailed structure of the single battery stack 200 shown).

[0071] The single battery stack 200 includes M parallel-connected single battery blocks (i.e., parallel single battery blocks 100-1 to 100-M). M voltage sensors (i.e., voltage sensors VB-1 to VB-M) are mounted on one voltage detection circuit 141. The voltage sensors VB-1 to VB-M are respectively configured to detect the inter-terminal voltage of the parallel single battery blocks 100-1 to 100-M. M can be 5 or more, or can be 30 or more. In this embodiment, M is set to 10.

[0072] The parallel single battery blocks 100-1 to 100-M are connected in series via the power line PL13. Each power line PL13 serially connects adjacent parallel single battery blocks to each other inside the single battery stack 200. The power line PL A 、PL B are power lines for connecting the single battery stack 200 to the outside. In this embodiment, the power line PL A is the positive-side power line of the single battery stack 200, and the power line PL B is the negative-side power line of the single battery stack 200. Hereinafter, unless otherwise distinguished, each of the parallel single battery blocks 100-1 to 100-M is referred to as "parallel single battery block 100".

[0073] Each parallel single battery block 100 includes a plurality of single batteries 10 (lithium ion secondary batteries in this embodiment) connected in parallel. The number of single batteries 10 included in each parallel single battery block 100 is arbitrary, but in this embodiment, it is set to 3. In each parallel single battery block 100, the positive electrodes of the 3 single batteries 10 are connected in parallel via the power line PL11, and the negative electrodes of the 3 single batteries 10 are connected in parallel via the power line PL12. Each of the power lines PL11 and PL12 can be a wire or a metal plate (e.g., a bus bar). Each single battery 10 included in the parallel single battery block 100 can also be connected to the power line PL11 or PL12 via a fuse (not shown).

[0074] In this embodiment, each parallel single-cell block 100 includes the same number (more specifically, three) of single cells 10. However, the number of single cells included in one parallel single-cell block is not limited to three but can be arbitrary. For example, each parallel single-cell block may also include five or more single cells. Additionally, the number of single cells can be different for each parallel single-cell block.

[0075] The single-cell stacks 200-1 to 200-N are connected in series via the power line PL3 to form the battery pack 130. The battery pack 130 includes N×M parallel single-cell blocks 100. The number of parallel single-cell blocks included in the battery pack 130 can be 50 or more, or can be 100 or more. In this embodiment, the number of parallel single-cell blocks included in the battery pack 130 is 100. The capacity of the battery pack 130 can be 30 Ah or more, or can be 100 Ah or more.

[0076] The power lines PL1 and PL2 are power lines for connecting the battery pack 130 to the outside. In this embodiment, the power line PL1 is the power line on the positive electrode side of the battery pack 130, and the power line PL2 is the power line on the negative electrode side of the battery pack 130. The power line PL1 corresponds to the power line PL of the single-cell stack 200-1 A . The power line PL2 corresponds to the power line PL of the single-cell stack 200-N B . In this embodiment, the current sensor IB is arranged on the power line PL2. However, it is not limited to this, and the current sensor IB can also be arranged on the power line PL1. The current sensor IB detects the total current flowing through all the single cells 10 that make up each parallel single-cell block 100.

[0077] Figure 3 is a diagram showing the detailed structure of the ECU 500. Referring to Figure 1 and Figure 2 together Figure 3 , the ECU 500 includes a battery resistance measurement system 510 and a control system 520. In the ECU 500, the battery resistance measurement system 510 functions as an example of the "battery resistance measurement device" of the present disclosure, and the control system 520 functions as an example of the "control device" of the present disclosure.

[0078] The battery resistance measurement system 510 includes a judgment unit 511, a measurement unit 512, and a diagnosis unit 513. The control system 520 includes a charge control unit 521, a mode switching unit 522, and an air-conditioning control unit 523. In this embodiment, through Figure 1 the processor 501 shown and the program executed by the processor 501, these units are implemented. However, it is not limited to this, and these units can also be implemented by dedicated hardware (electronic circuits).

[0079] The ECU 500 obtains the state of the battery pack 130 from the monitoring module 140. Output signals of the voltage sensors VB-1 to VB-M are input to the ECU 500 via the voltage detection circuit 141 which is a circuit common to these sensors. That is, each voltage detection circuit 141 processes M sensor signals and outputs them to the ECU 500. The output signal of the current sensor IB is input to the ECU 500 via the current detection circuit 142. The output signal of the temperature sensor TB is input to the ECU 500 via the temperature detection circuit 143.

[0080] The charge control unit 521 is configured to control the input current of the battery pack 130 so as to avoid the input power of the battery pack 130 exceeding the input limit value. The charge control unit 521 is configured to obtain the temperature of the battery pack 130 from the temperature detection circuit 143 and set the input limit value according to the temperature of the battery pack 130. Hereinafter, the input limit value may sometimes be referred to as "Win". The charge control unit 521 of this embodiment sets Win based on the Figure 4 mapping shown below.

[0081] Figure 4 is a diagram showing a mapping that defines the relationship between the temperature of the battery pack 130 and Win. In this embodiment, the power on the discharge side is represented by positive (+), and the power on the charge side is represented by negative (-). However, when comparing the magnitudes of powers, they are compared by absolute value regardless of the plus / minus sign (+ / -). That is, the closer the value is to 0, the smaller the power.

[0082] Refer to Figure 4 , the mapping shown by line L1 defines the relationship between the temperature of the battery pack 130 and Win. According to this mapping, in the low temperature region, the higher the temperature of the battery pack 130, the larger Win is on the negative side. If the temperature of the battery pack 130 is higher than the above low temperature region, Win is substantially constant. This mapping defines Win for each temperature of the battery pack 130 in a manner that avoids the precipitation of lithium metal on the negative electrode of the lithium ion secondary battery (single cell 10) included in the battery pack 130. The charge control unit 521 can set Win in a manner that avoids the precipitation of lithium metal on the negative electrode of the lithium ion secondary battery by using the above mapping. The charge control unit 521 sets Win (input limit value) according to the above mapping such that Win when the temperature of the battery pack 130 is lower than Th1 is lower than Win when the temperature of the battery pack 130 is higher than Th1. Figure 4 Th1 in Figure 4 is an example of the "predetermined temperature" of the present disclosure. Regarding L the temperature T H shown later.

[0083] Again with Figure 1 and Figure 2 refer to togetherFigure 3 The charging control unit 521 controls the input current of the battery pack 130 in such a way as to avoid the input power of the battery pack 130 from exceeding Win set based on the above mapping. The charging control unit 521 can adjust the input current of the battery pack 130 by controlling, for example, the DC charger 120. In addition, the input power exceeding Win means that the input power is larger than Win on the negative side (i.e., away from 0 towards the negative side). In addition, Figure 4 only the input limit value (Win) is shown, but it is also possible to set an output limit value (upper limit value of output power) of the battery pack 130 in addition to the input limit value (upper limit value of input power) of the battery pack 130.

[0084] The mode switching unit 522 is configured to perform the switching of the aforementioned control modes. The mode switching unit 522 performs, for example, the Figure 5 processing shown below.

[0085] Figure 5 is a flowchart showing the processing related to the switching of the control mode executed by the ECU 500. If the user performs a predetermined operation (screen display operation) on the input device 160 during external charging of the battery pack 130, the processing shown in this flowchart starts.

[0086] Together with Figures 1 - 3 refer to Figure 5 In S101, the mode switching unit 522 controls the notification device 170 so as to display a selection screen on the notification device 170. The selection screen is a screen that urges the user to select (more specifically, input a selection of either the normal mode or the my room mode) the control mode.

[0087] Figure 6 is a diagram showing an example of the selection screen. Together with Figure 5 refer to Figure 6 This selection screen displays a message M1, an option M2 for "my room mode", an option M3 for "cancel", and a cursor M4, and urges the user to select either option M2 or M3. The user can select either option M2 or M3 by operating the input device 160, for example. For example, the input device 160 may include a direction key (arrow button) and a decision button. And the user can select either option M2 or M3 by aligning the cursor M4 with either option M2 or M3 using the direction key and pressing the decision button.

[0088] In Figure 5 S102, the mode switching unit 522 determines whether the my room mode has been selected by the user. In Figure 6In the displayed selection screen, if the user selects option M2, it is determined to be "yes" in S102. On the other hand, if the user selects option M3, it is determined to be "no" in S102. In the case where neither option M2 nor M3 is selected after a predetermined time (e.g., 100 seconds) has elapsed since the selection screen was displayed in S101, it is also determined to be "no" in S102.

[0089] Again, referring to Figures 1 - 3 together with Figure 5 , if it is determined to be "yes" in S102, the mode switching unit 522 executes the my room mode in S103. On the other hand, if it is determined to be "no" in S102, the mode switching unit 522 executes the normal mode in S104. After the process of S103 or S104 is executed, the mode switching unit 522 ends the display of the selection screen by the notification device 170 in S105. Through the process of S105, the notification device 170 can be in a non-display state, or the main screen can be displayed instead of the selection screen. By executing the process of S105, Figure 5 the series of processes shown ends.

[0090] Again, referring to Figure 1 and Figure 2 together with Figure 3 , the air conditioner control unit 523 is configured to control the air conditioner device 320. For example, the input device 160 may also include an operation panel of the air conditioner device 320. The user can turn on the power of the air conditioner device 320 or input the target temperature of the air conditioner device 320 through the operation panel. In this embodiment, the air conditioner control unit 523 controls the air conditioner device 320 based on the input from the user. However, when the mode switching unit 522 is executing the normal mode during the external charging of the battery pack 130, the air conditioner control unit 523 cannot drive the air conditioner device 320. In the normal mode, the mode switching unit 522 controls the DC / DC converter 310 during the external charging of the battery pack 130 and cuts off the power supply path from the storage battery 300 to the air conditioner device 320 using the DC / DC converter 310. As a result, the use of the air conditioner device 320 during the external charging of the battery pack 130 is prohibited.

[0091] The determination unit 511 determines whether the battery pack 130 has switched from the charging state to the discharging state (power receiving state) based on whether a predetermined condition (hereinafter referred to as "measurement start condition") is satisfied. The measurement start condition is set to be satisfied when the battery pack 130 switches from the charging state to the discharging state (power receiving state) after the start of the external charging of the battery pack 130. The discharging state (power receiving state) is a discharging state in which the battery pack 130 outputs power greater than the supplied power while receiving power supply.

[0092] The measurement start condition includes the following requirements a to c. In this embodiment, the measurement start condition is satisfied when the requirements a to c are satisfied. In addition, Th1 in requirement c means Figure 4 The same temperature as "Th1".

[0093] (Requirement a) ECU 500 is executing the my room mode.

[0094] (Requirement b) Air conditioner 320 is driven after external charging of battery pack 130 starts.

[0095] (Requirement c) The temperature of the battery pack 130 is lower than a predetermined temperature (hereinafter referred to as “Th1”).

[0096] Below, use Figures 7 - 10 The measurement start conditions are explained below. Figures 7 - 10 In the diagram, the current on the discharge side is represented by positive (+), and the current on the charge side is represented by negative (-).

[0097] Figure 7 1 is a diagram showing an example of the current of the battery pack 130 when the air conditioner 320 is driven during external charging of the battery pack 130 in a low temperature state in the my room mode (permission mode). Figure 7 In the example shown, the temperature of the battery pack 130 is Figure 4 The temperature T shown L .and Figure 4 Refer to Figure 7 In the My Room mode, when the air conditioner 320 is driven during the external charging of the battery pack 130 in a low temperature state, the battery pack 130 receives power supply from the outside of the vehicle and outputs power greater than the supplied power to the air conditioner 320. Since the temperature of the battery pack 130 is low, Win (input limit value) becomes smaller ( Figure 4 ). In this embodiment, when the temperature of the battery pack 130 is lower than Th1, Win is smaller than the driving power of the air conditioner 320. Figure 7 In the example shown, a current of -10A is input to the battery pack 130 from the outside of the vehicle via the DC charger 120. When the temperature of the battery pack 130 is T L ( Figure 4 ), when the input current of the battery pack 130 is -10A, the input power of the battery pack 130 is consistent with Win. The input current of the battery pack 130 is limited by Win. The battery pack 130 receives the supply of power equivalent to Win and outputs power for driving the air conditioner 320. Figure 7In the example shown, a current of 15 A is output from the battery pack 130 to the air conditioner 320. Therefore, the battery pack 130 is in a discharging state (while receiving power). The discharging current of the battery pack 130 is substantially 5 A.

[0098] Figure 8 FIG. is an example showing the current of the battery pack 130 during external charging in the normal mode (prohibited mode). In Figure 8 the example shown, the temperature of the battery pack 130 is Figure 4 the temperature T shown L . Together with Figure 4 refer to Figure 8 , in the normal mode, the battery pack 130 during external charging does not output power to the air conditioner 320. In the normal mode, during external charging of the battery pack 130, the power path is cut off by the DC / DC converter 310, and the driving of the air conditioner 320 is prohibited. In Figure 8 the example shown, a current of -10 A is input to the battery pack 130 from outside the vehicle via the DC charger 120, and no current is output from the battery pack 130. Thus, in Figure 8 the example shown, the battery pack 130 is in a charging state. The charging current of the battery pack 130 is -10 A. In addition, when the user does not use the air conditioner 320 during external charging of the battery pack 130 in the my room mode, the battery pack 130 also becomes the same state as Figure 8 the state shown.

[0099] Figure 9 FIG. is an example showing the current of the battery pack 130 when the air conditioner 320 is driven during external charging of the battery pack 130 in the high temperature state in the my room mode (permitted mode). In Figure 9 the example shown, the temperature of the battery pack 130 is Figure 4 the temperature TH shown. Together with Figure 4 refer to Figure 9 , when the air conditioner 320 is driven during external charging of the battery pack 130 in the high temperature state in the my room mode, the battery pack 130 receives power supply from outside the vehicle while outputting power smaller than the supplied power to the air conditioner 320. Since the temperature of the battery pack 130 is high, Win (input limit value) becomes larger ( Figure 4 ). In this embodiment, when the temperature of the battery pack 130 is higher than Th1, Win is larger than the driving power of the air conditioner 320. In Figure 9 the example shown, a current of -20 A is input to the battery pack 130 from outside the vehicle via the DC charger 120. The battery pack 130 receives such power supply while outputting power for driving the air conditioner 320. In Figure 9In the example shown, a current of 15 A is output from the battery pack 130 to the air conditioner 320. Therefore, after the air conditioner 320 is driven, the battery pack 130 also maintains a charged state. The charging current of the battery pack 130 substantially becomes -5 A.

[0100] For example, when external charging of the battery pack 130 is performed at a low outside air temperature and during this external charging, the user of the vehicle 50 instructs the ECU 500 to execute the my room mode and the vehicle interior is heated using the air conditioner 320, it is easy to satisfy all of the above requirements a to c. In this case, it can be considered that requirement b is finally satisfied in a state where requirements a and c are satisfied. By satisfying requirement b, the battery pack 130, for example, changes from Figure 8 the state shown to Figure 7 the state shown. That is, during the external charging of the battery pack 130, the battery pack 130 switches from a charged state to a discharged state (while receiving power).

[0101] Figure 10 FIG. is an example showing the transition of the current of the battery pack 130 when the measurement start condition is satisfied during the external charging of the battery pack 130. Figure 10 The current value shown in is the substantial current value of the battery pack 130 obtained by combining the input current and the output current of the battery pack 130. Figure 10 t1 to t3 in represent timings.

[0102] With Figure 7 and Figure 8 referred to together Figure 10 In this example, in my room mode starts at t1 and the driving of the air conditioner 320 starts at t2. As shown by line L2, by driving the air conditioner 320, the current value of the battery pack 130 gradually increases toward the positive (+) side, and the battery pack 130 changes from Figure 8 the state shown to Figure 7 the state shown. At t3 in the middle of the transition from Figure 8 the state shown to Figure 7 the state shown, the battery pack 130 switches from a charged state to a discharged state (while receiving power).

[0103] As described above, when the measurement start condition is satisfied, the battery pack 130 switches from a charged state to a discharged state (while receiving power). Therefore, Figure 3The determination unit 511 shown can accurately determine whether the battery pack 130 has switched from the charging state to the discharging state (while receiving power) based on whether the measurement start condition is satisfied. The determination unit 511 of this embodiment determines that the battery pack 130 has switched from the charging state to the discharging state (while receiving power) at the timing when the measurement start condition is satisfied. However, it is not limited thereto, and the determination unit 511 may also determine that the battery pack 130 has switched from the charging state to the discharging state (while receiving power) at the timing when a predetermined time (for example, about 15 seconds) has elapsed since the measurement start condition was satisfied.

[0104] Again with Figure 1 and Figure 2 refer to together Figure 3 , the measurement unit 512 starts measuring the resistance of the battery pack 130 at the charge-discharge switching timing. The charge-discharge switching timing is the timing when the battery pack 130 switches from the charging state to the discharging state (while receiving power). Whether the charge-discharge switching timing has arrived is determined by the determination unit 511. Hereinafter, the method for measuring the resistance of the battery pack 130 will be described using Figure 11 .

[0105] Figure 11 is a graph showing the relationship between the current and voltage actually measured by the inventor of the present application for the battery pack 130 of this embodiment. The inventor of the present application plotted the measured values on a plane with the voltage of the battery pack 130 on the vertical axis and the current of the battery pack 130 on the horizontal axis, and obtained a regression line (line L3) by the least squares method.

[0106] Refer to Figure 11 , in the region where the current of the battery pack 130 is small (close to 0), the plotted data lies on the regression line (line L3). That is, the voltage and current of the battery pack 130 have a linear relationship. On the other hand, if the current of the battery pack 130 increases to the positive side (discharging side) or the negative side (charging side), the relationship between the voltage and current of the battery pack 130 becomes non-linear.

[0107] Figure 3The measurement unit 512 shown obtains the resistance of the battery pack 130 based on the slope of the regression line (line L3). In this embodiment, the measurement unit 512 measures the resistance for each parallel single-cell block included in the battery pack 130. The measurement unit 512 measures the current and voltage during the discharge of the battery pack 130, and obtains the relationship between the voltage and the current for each parallel single-cell block. Then, the measurement unit 512 obtains the resistance for each parallel single-cell block based on the obtained relationship (more specifically, the slope of the regression line). The measurement unit 512 starts the measurement of the current and voltage of the battery pack 130 at the charge-discharge switching timing. At the charge-discharge switching timing, it can be considered that the current of the battery pack 130 is small. By starting the measurement at such a timing, the measurement unit 512 can measure the resistance of each parallel single-cell block with high accuracy. In addition, the measurement unit 512 may also obtain the OCV (Open Circuit Voltage) of the battery pack 130 based on the intercept of the regression line (line L3).

[0108] In addition, at the charge-discharge switching timing, the polarization generated during the charging of the battery pack 130 is canceled out by the discharge of the battery pack 130 and becomes smaller. By reducing the polarization in the battery pack 130, the voltage drop of the battery pack 130 caused by the charging history is suppressed. It can be considered that the effect of such discharge also makes the relationship between the voltage and current of the battery pack 130 closer to linearity.

[0109] Again with Figure 1 and Figure 2 together with reference to Figure 3 , the diagnosis unit 513 is configured to use the resistance of each parallel single-cell block measured by the measurement unit 512 to diagnose the presence or absence of a disconnection of the parallel single-cell block 100 included in the battery pack 130. Hereinafter, the disconnection diagnosis method performed by the diagnosis unit 513 will be described using Figure 12 to illustrate.

[0110] Figure 12 is a diagram showing an example of the current when a disconnection occurs in the parallel single-cell block 100 during charging. Figure 12 The parallel single-cell block 100 shown is composed of single cells 10a to 10c connected in parallel.

[0111] Refer to Figure 12, in this example, a disconnection occurs at the portion PLx near the single cell 10a, and the electrical connection between the single cell 10a and the power line PL11 is disconnected. Due to this disconnection, the single cell 10a detaches from the parallel single cell block 100, and the number of single cells constituting the parallel single cell block 100 substantially becomes two. Therefore, during charging of the parallel single cell block 100, current does not flow to the single cell 10a, and current only flows to the remaining single cells 10b and 10c. As a result, the magnitude of the current flowing through each single cell during charging becomes approximately 1.5 times that in the normal state (i.e., when no detachment of the single cell occurs). If a disconnection occurs in the parallel single cell block 100 and any single cell 10 (e.g., single cell 10a) constituting the parallel single cell block 100 detaches, the current concentrates on the remaining single cells 10 (e.g., single cells 10b and 10c), and the resistance of the parallel single cell block 100 increases.

[0112] Reconnect with Figure 1 and Figure 2 refer to together Figure 3 , the diagnosis unit 513 uses any parallel single cell block 100 included in the battery pack 130 as the target block, and uses the degree of deviation between the resistance of the target block and the resistance of the adjacent block to diagnose the presence or absence of a disconnection in the target block. The adjacent block is a parallel single cell block 100 located beside the target block in one single cell stack 200. In this embodiment, when there are parallel single cell blocks 100 on both the positive electrode side and the negative electrode side of the target block in the single cell stack 200, the parallel single cell block 100 on the positive electrode side is used as the adjacent block. For example, when the parallel single cell block 100-2 shown in Figure 2 is the target block, the parallel single cell block 100-1 located beside the positive electrode side of the target block becomes the adjacent block. On the other hand, when the parallel single cell block 100-1 at the end of the positive electrode side in the single cell stack 200 is the target block, there is no parallel single cell block 100 beside the positive electrode side of the target block, so the parallel single cell block 100-2 located beside the negative electrode side of the target block becomes the adjacent block.

[0113] In this embodiment, as the degree of deviation, the resistance ratio (i.e., the ratio of the resistance of the target block to the resistance of the adjacent block) is used. The resistance ratio is a value obtained by dividing the resistance of the target block by the resistance of the adjacent block (= resistance of the target block / resistance of the adjacent block). The diagnosis unit 513 determines that a disconnection has occurred in the target block when the resistance ratio is greater than a predetermined value (hereinafter, denoted as "Th2"). In this embodiment, Th2 is greater than 1. In addition, the resistance of each of the target block and the adjacent block is measured by the measurement unit 512 by the aforementioned method. The measurement error of the resistance of each block (especially the detection error of the voltage detection circuit 141 and the current detection circuit 142) is canceled out when calculating the ratio.

[0114] Although details will be described later, the diagnostic unit 513 of this embodiment is configured to diagnose whether at least one parallel single cell block 100 included in the battery pack 130 has no disconnection by using the resistance of each parallel single cell block 100 measured by the measurement unit 512 (see Figure 14 ). In this diagnosis, the diagnostic unit 513 performs diagnosis on the object block while sequentially changing the object block.

[0115] Figure 13 FIG. is a flowchart showing the battery resistance measurement method of this embodiment. When the external charging of the battery pack 130 starts, Figure 13 the series of processes shown starts.

[0116] Together with Figures 1 - 3 refer to Figure 13 , the determination unit 511 determines whether the measurement start condition is satisfied in S11 to S14.

[0117] In S11, the determination unit 511 determines whether the battery pack 130 is receiving power supply from outside the vehicle 50. For example, when the external charging of the battery pack 130 ends, the power supply from outside the vehicle to the connection port 110 stops, and no power is output from the DC charger 120 to the battery pack 130. In this case, it is determined as No in S11, Figure 13 and the series of processes shown ends.

[0118] On the other hand, when power is being output from the DC charger 120 to the battery pack 130, it is determined as Yes in S11. In this case, the process proceeds to S12. After that, if it is determined as Yes in all of S12 to S14, the process proceeds to S15. On the other hand, if it is determined as No in any one of S12 to S14, the process returns to the initial step (S11).

[0119] In S12, the determination unit 511 determines whether the temperature of the battery pack 130 is lower than Th1. In addition, during the external charging of the battery pack 130, Win (the input limit value of the battery pack 130) changes according to the temperature of the battery pack 130 (see Figure 4 ).

[0120] In S13, the determination unit 511 determines whether the mode switching unit 522 is executing the My Room mode. During the external charging of the battery pack 130, the user can make the mode switching unit 522 execute the My Room mode by calling up Figure 5 the process shown and selecting the My Room mode in the selection screen ( Figure 6 ).

[0121] In S14, the determination unit 511 determines whether the air conditioner 320 is driven. In the my room mode, the user can operate the input device 160 to start driving the air conditioner 320.

[0122] Determining yes in all of S11 to S14 means that the aforementioned requirements a to c are satisfied. And, when the requirements a to c are satisfied, the determination unit 511 determines that the measurement start condition is established. Further, when the measurement start condition is established, the determination unit 511 determines that the charge / discharge switching timing has arrived. If it is determined yes in all of S11 to S14, the measurement unit 512 starts measuring the resistance of the battery pack 130 in S15. In S15, the measurement unit 512 measures the resistance of each parallel single cell block 100 included in the battery pack 130, and saves the measured data (resistance) in the storage device 503 ( Figure 1 ). After that, the process proceeds to S16.

[0123] In S16, the diagnosis unit 513 diagnoses the presence or absence of disconnection of all the parallel single cell blocks 100 included in the battery pack 130 using the resistance of each parallel single cell block 100 measured in S15 above.

[0124] Figure 14 is a flowchart showing Figure 13 the details of the battery diagnosis process (S16) shown. Together with Figures 1 - 3 refer to Figure 14 , in S21, the diagnosis unit 513 sets any one of the single cell stacks 200 included in the battery pack 130 as the target stack. The diagnosis unit 513 changes the target stack every time the process of S21 is executed. In this embodiment, the diagnosis unit 513 sequentially sets the single cell stacks 200-1 to 200-N included in the battery pack 130 as the target stack from the positive electrode side. That is, initially, the single cell stack 200-1 is set as the target stack. However, the setting order of the target stack in S21 is not limited to the above and is arbitrary.

[0125] In S22, the diagnosis unit 513 sets any one of the parallel single cell blocks 100 included in the target stack set in S21 above as the target block. The diagnosis unit 513 changes the target block every time the process of S22 is executed. In this embodiment, the diagnosis unit 513 sequentially sets the parallel single cell blocks 100-1 to 100-M included in the target stack as the target block from the positive electrode side. That is, initially, the parallel single cell block 100-1 is set as the target block. However, the setting order of the target block in S22 is not limited to the above and is arbitrary.

[0126] In S23, the diagnosis unit 513 obtains the resistance of the target block set in S22 above. Then, the diagnosis unit 513 obtains the resistance of the adjacent block in S24. The resistance of each of the target block and the adjacent block is in Figure 13measured in S15 and stored in the storage device 503 ( Figure 1 ).

[0127] In S25, the diagnosis unit 513 calculates a resistance ratio by dividing the resistance of the target block obtained in the above S23 by the resistance of the adjacent block obtained in the above S24. Next, in S26, the diagnosis unit 513 determines whether the resistance ratio is greater than Th2. Th2 is a threshold for determining whether a disconnection has occurred in the parallel single cell block 100. When a disconnection occurs in the target block, the resistance ratio is greater than Th2. The resistance ratio being greater than Th2 means that the resistance deviation degree is greater than a predetermined level and the resistance of the target block is greater than the resistance of the adjacent block.

[0128] When the resistance ratio is equal to or less than Th2 (No in S26), the diagnosis unit 513 determines that no disconnection has occurred in the target block, and the process proceeds to S27. In S27, the diagnosis unit 513 determines whether the diagnosis of all the parallel single cell blocks 100 included in the target stack has been completed. In this embodiment, when the above diagnosis (S23 to S26) is performed on the parallel single cell block 100-M as the target block, it is determined to be Yes in S27, and the process proceeds to S29. Determining Yes in S27 means that no disconnection has occurred in the target stack. The diagnosis unit 513 may notify and / or record such a diagnosis result.

[0129] When the diagnosis of any of the parallel single cell blocks 100 in the target stack has not been completed (No in S27), the process returns to S22, and in S22, the target block is changed, and the above diagnosis (S23 to S26) is performed on the changed target block. For example, after the parallel single cell block 100-1, the parallel single cell block 100-2 is set as the target block.

[0130] When the resistance ratio is greater than Th2 (Yes in S26), the diagnosis unit 513 determines that a disconnection has occurred in the target stack, and the process proceeds to S28. In S28, the diagnosis unit 513 performs a predetermined abnormality detection process. The predetermined abnormality detection process may include recording information indicating the diagnosis result (that is, a disconnection has occurred in the target stack). The diagnosis result can be recorded in the storage device 503 ( Figure 1 ). The recorded diagnosis result can also be used in OBD (self-diagnosis). The predetermined abnormality detection process may also include notification of the diagnosis result. The notification of the diagnosis result can be performed by the notification device 170 ( Figure 1)It is carried out. The notification method is arbitrary. It can notify the user by displaying on the display device (for example, displaying text or images), or can notify the user by the speaker through sound (including voice), or can also turn on a predetermined lamp (including flashing). The predetermined abnormality detection process can also include sending the diagnosis result. The diagnosis result can be sent to a server (not shown) outside the vehicle. After the process of S28 is executed, the process proceeds to S29.

[0131] In S29, the diagnosis unit 513 determines whether the diagnosis of all the single battery stacks 200 included in the battery pack 130 has been completed. If the diagnosis of any single battery stack 200 has not been completed (No in S29), the process returns to S21, and in S21, the target stack is changed. For example, after the single battery stack 200-1, the single battery stack 200-2 is set as the target stack. Then, the above-mentioned diagnosis (S22 to S26) is performed on each parallel single battery block 100 included in the changed target stack.

[0132] In this embodiment, when the above-mentioned diagnosis (S22 to S26) is performed with the single battery stack 200-N as the target stack, it is judged as Yes in S29. If it is judged as Yes in S29, then Figure 14 The series of processes shown end. Thus, Figure 13 The process of S16 ends, Figure 13 The series of processes also end.

[0133] As described above, the battery resistance measurement method of this embodiment is a method for measuring the resistance of the battery pack 130 (target battery). This battery resistance measurement method includes the following judgment process ( Figure 13 S11 to S14 of Figure 13 ) and a measurement start process ( S15 of ). In the judgment process, it is judged whether the battery pack 130 has switched from the charging state to the discharging state (while receiving power) based on whether a predetermined measurement start condition is satisfied. In the measurement start process, when it is judged that the battery pack 130 has switched from the charging state to the discharging state (while receiving power) (Yes in all of S11 to S14), the measurement of the resistance of the battery pack 130 is started. According to such a battery resistance measurement method, the resistance of the battery pack 130 can be measured during a period with little influence of polarization. Therefore, even without measuring the polarization state of the battery pack 130, the resistance of the battery pack 130 can be measured with sufficient accuracy. In this way, the above battery resistance measurement method can simply and accurately measure the resistance of the battery pack 130.

[0134] The above measurement start conditions can be appropriately changed. For example, when Win is always set low and Win is always smaller than the driving power of the air conditioner 320 regardless of the temperature of the battery pack 130, requirement c can also be omitted. That is, the measurement start condition can also be established when requirements a and b are satisfied.

[0135] Figure 15 is a diagram showing Figure 13 a modified example of the process shown. Figure 15 The process shown except that S12 ( Figure 13 ) is omitted is the same as the process shown in Figure 13 . By the ECU 500 executing the process shown in Figure 13 instead of the process shown, the measurement start condition is established when requirements a and b are satisfied. Figure 15

[0136] In the above embodiment, requirement b is satisfied when the air conditioner 320 is driven after the external charging of the battery pack 130 starts. However, requirement b can also be changed to be satisfied when other auxiliary machines are driven instead of or in addition to the air conditioner 320. Similar to the air conditioner 320, other auxiliary machines can also be included in the target auxiliary machines of the normal mode and the my room mode. Other auxiliary machines can also be various heaters (for example, at least one of a seat heater and a rearview mirror heater).

[0137] In the above embodiment, when there are parallel single cell blocks 100 on both the positive electrode side and the negative electrode side of the target block in the single cell stack 200, the parallel single cell block 100 on the positive electrode side is used as the adjacent block. However, it is not limited thereto, and each of the two parallel single cell blocks 100 located on both sides of the target block can also be used as the adjacent block. For example, in the process shown in Figure 14 , in S25, the resistance ratio can also be calculated for each of the two parallel single cell blocks 100 located on both sides of the target block, and in S26, each resistance ratio can be compared with Th2. And when at least one of the resistance ratios is larger than Th2, it can be determined as yes in S26.

[0138] The diagnostic method of the battery using the battery resistance is not limited to the method shown in Figure 14 . For example, the ECU 500 can also use AI (artificial intelligence) to analyze the data measured by the measurement unit 512 (that is, the resistance of each parallel single cell block 100 included in the battery pack 130), and diagnose which parallel single cell block 100 has an abnormality.

[0139] ​In the above-described embodiment, the battery resistance measurement system 510 and the control system 520 are mounted on one computer (ECU 500), but the battery resistance measurement system 510 and the control system 520 may also be respectively mounted on a plurality of computers. Further, the charging control unit 521 and the air conditioner control unit 523 may also be respectively mounted on a plurality of computers.

[0140] Alternatively, at least one of the input device 160 and the notification device 170 mounted on the vehicle 50 may be replaced with a portable terminal carried by the user of the vehicle 50. The portable terminal can function as both an input device and a notification device. The portable terminal may also be configured to communicate wirelessly with the ECU 500. The user can handle such a portable terminal in the same manner as the input device 160 and the notification device 170. Examples of the portable terminal include a tablet terminal, a smartphone, a wearable device, an electronic key, or a service tool.

[0141] The target battery whose resistance is measured by the battery resistance measurement device is not limited to the battery pack 130, and may also be a single secondary battery (e.g., a lithium-ion secondary battery). Further, the target battery is not limited to the battery mounted on the vehicle. The target battery may also be used in a vehicle other than a vehicle (such as a ship, an airplane, etc.), an unmanned moving body (such as an automated guided vehicle (AGV), an agricultural machine, a mobile robot, a drone, a space probe, etc.), an assembly robot (e.g., a nursing robot), a stationary robot (e.g., an industrial robot), or a building (such as a house, a factory, etc.).

[0142] Although embodiments of the present invention have been described, it should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is represented by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A vehicle, comprising: An object battery; A battery resistance measuring device that measures the resistance of the battery; The battery resistance measuring device includes: A judgment unit that judges whether the object battery has switched from a charging state to a discharging state in which power is supplied while outputting power greater than the supplied power, based on whether a predetermined condition is satisfied; A measuring unit that starts measuring the resistance of the object battery at the timing when the judgment unit judges that the object battery has switched from the charging state to the discharging state, where the object battery is a battery pack including a plurality of parallel single battery blocks; and A diagnosis unit that uses the resistance of any one of the parallel single battery blocks included in the battery pack as an object block to diagnose the presence or absence of a disconnection of the object block, Each of the plurality of parallel single battery blocks includes a plurality of secondary batteries connected in parallel, The plurality of parallel single battery blocks are connected in series with each other, The measuring unit is configured to measure the resistance of at least one parallel single battery block included in the battery pack, The measuring unit measures the resistance of the parallel single battery block based on the slope of the regression line of the parallel single battery block, where the regression line is obtained based on the current and voltage of the parallel single battery block measured in advance, An auxiliary machine that receives power supply from the object battery; And A control device that switches between multiple control modes, Among them, the multiple control modes include: A prohibition mode that prohibits driving the auxiliary machine using the power output from the object battery when the object battery is receiving power supply from outside the vehicle; and A permission mode that permits driving the auxiliary machine using the power output from the object battery when the object battery is receiving power supply from outside the vehicle, The predetermined condition includes: The control device is executing the permission mode; and After starting charging the object battery using the power supplied from outside the vehicle, the auxiliary machine is driven.

2. The vehicle according to claim 1, The auxiliary machine is an air conditioning device that performs air conditioning inside the vehicle.

3. The vehicle according to claim 1 or 2, The control device is configured to: set an input limit value according to the temperature of the object battery, and control the input current of the object battery so that the input power of the object battery does not exceed the input limit value, The control device is configured to: set the input limit value in such a way that the input limit value when the temperature of the object battery is lower than a predetermined temperature is lower than the input limit value when the temperature of the object battery is higher than the predetermined temperature, The predetermined condition further includes that the temperature of the object battery is lower than the predetermined temperature.

4. The vehicle according to claim 3, The object battery includes a lithium ion secondary battery, The control device sets the input limit value so that lithium metal does not precipitate on the negative electrode of the lithium ion secondary battery.

5. The vehicle according to claim 1, The diagnosis unit is configured to: diagnose the presence or absence of a disconnection of the object block using the deviation degree between the resistance of the object block and the resistance of the parallel single battery block adjacent to the object block in the battery pack.

6. The vehicle according to claim 1 or 5, wherein the measurement unit is configured to measure the resistance of each parallel single cell block included in the battery pack, and the diagnosis unit is configured to: sequentially change the target block, and use the resistance of each parallel single cell block measured by the measurement unit to diagnose the presence or absence of a disconnection in the battery pack.

7. The vehicle according to claim 1 or 5, wherein the measurement unit is configured to measure the current and voltage during discharge of the target battery, and use the measured current and voltage to measure the resistance of the target battery.

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