Electric powered vehicle and battery pack for electric powered vehicle

An electric powered vehicle may include a battery ECU housed in a battery pack and a vehicle ECU mounted on a vehicle body and communicably connected to the battery ECU. The vehicle ECU may be configured to transmit first and second identification data for detecting communication disruptions to the battery ECU. The battery ECU may be configured to: when the battery ECU receives both the first and the second identification data, determine that the battery ECU is communicably connected to the vehicle ECU and enable a predetermined mutual monitoring function for the vehicle ECU; and when the battery ECU receives the first identification data but does not receive the second identification data, determine that the battery ECU is communicably connected to another ECU other than the vehicle ECU and disable the mutual monitoring function for the vehicle ECU.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2020-104907, filed on Jun. 17, 2020, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The art disclosed herein relates to an electric powered vehicle and a battery pack for an electric powered vehicle.

BACKGROUND

In recent years, electric powered vehicles have been widely popularized. In connection to this, Japanese Patent Application Publication No. 2008-42985 describes a battery pack for an electric powered vehicle. This battery pack is provided with a battery ECU (Electronic Control Unit), and the battery ECU is communicably connected to an ECU mounted on the electric powered vehicle (hereinbelow termed a vehicle ECU). Generally, an electric powered vehicle includes various fail-safe designs, and a relatively sophisticated mutual monitoring function is incorporated for mutual communication between a battery ECU and a vehicle ECU.

SUMMARY

As electric powered vehicles are popularized, a large number of battery packs are manufactured and discarded. In view of this, it has been considered to reuse battery packs for electric powered vehicles as power sources in facilities, stores, and the like. Here, reusing a battery pack for an electric powered vehicle in another application without making any modifications to it requires an ECU of a system in which the battery pack is to be reused (hereinbelow, a system in which a battery pack is reused or is to be reused will be termed “battery-pack reusing system”) to also have the sophisticated mutual monitoring function of the battery ECU. However, it is not typically expected that in the facility or store where the battery pack is to be reused, a fail-safe design equivalent to that of the electric powered vehicle is required. Therefore, providing the mutual monitoring function to an ECU of a battery-pack reusing system, just to match the battery ECU, may bring forth an unnecessary cost increase.

In view of the foregoing, the disclosure herein provides art that facilitates reuse of a battery pack for an electric powered vehicle in another application.

An electric powered vehicle disclosed herein may comprise a vehicle body comprising a traction motor; a battery pack mounted on the vehicle body and configured to supply electric power to the traction motor; a battery ECU housed in the battery pack; and a vehicle ECU mounted on the vehicle body and communicably connected to the battery ECU. The vehicle ECU may be configured to transmit first identification data and second identification data for detecting communication disruptions to the battery ECU. The battery ECU may be configured to, when the battery ECU receives both the first identification data and the second identification data, determine that the battery ECU is communicably connected to the vehicle ECU and enable a predetermined mutual monitoring function for the vehicle ECU; and when the battery ECU receives the first identification data but does not receive the second identification data, determine that the battery ECU is communicably connected to another ECU other than the vehicle ECU and disable the mutual monitoring function for the vehicle ECU.

In the above-described electric powered vehicle, the battery ECU housed in the battery pack is configured to monitor receipt of the first identification data and the second identification data in mutual communication with an ECU of apparatus or system to which the battery ECU is applied (such as the vehicle ECU). When the battery ECU receives both the first identification data and the second identification data, the battery ECU determines that it is communicably connected to the vehicle ECU. Contrary to this, when the battery ECU receives the first identification data but does not receive the second identification data, the battery ECU determines that it is communicably connected to another ECU other than the vehicle ECU, such as an ECU of a battery-pack reusing system. Thus, while the battery pack is mounted on the electric powered vehicle, fail-safe performance required for the electric powered vehicle can be satisfied by the battery ECU executing the mutual monitoring function with the vehicle ECU. On the other hand, once the battery pack is applied in a battery-pack reusing system, the battery ECU autonomously determines the change in application and disables the mutual monitoring function which is not required therein. Therefore, it is sufficient to provide the ECU of the battery-pack reusing system with a function of sending the first identification data, and significant modifications are not required. Also, the battery pack does not require special modifications either when applied in the battery-pack reusing system. This facilitates reuse of the battery pack for the electric powered vehicle in another application.

A battery pack for an electric powered vehicle is also disclosed herein. The electric powered vehicle may comprise a vehicle body comprising a traction motor and a vehicle ECU mounted on the vehicle body. The vehicle ECU may be configured to output first identification data and second identification data for detecting communication disruptions to a battery ECU. The battery pack may comprise at least one battery cell configured to supply electric power to the traction motor and the battery ECU communicably connected to the vehicle ECU when mounted on the electric powered vehicle. The battery ECU may be configured to, when the battery ECU receives both the first identification data and the second identification data, determine that the battery ECU is communicably connected to the vehicle ECU and enable a predetermined mutual monitoring function for the vehicle ECU; and when the battery ECU receives the first identification data but does not receive the second identification data, determine that the battery ECU is communicably connected to another ECU other than the vehicle ECU and disable the mutual monitoring function for the vehicle ECU.

The above battery pack also ensures that the battery ECU executes the mutual monitoring function for the vehicle ECU while the battery pack is mounted on the electric powered vehicle. When the battery pack is applied in a battery-pack reusing system, the battery ECU can stop executing the mutual monitoring function which is unnecessary therein. Thus, this battery pack for the electric powered vehicle can facilitate reuse of the battery pack in another application.

DETAILED DESCRIPTION

An electric powered vehicle10according to an embodiment will be described with reference toFIGS.1and2. As shown inFIG.1, the electric powered vehicle10includes a vehicle body12and a plurality of wheels14f,14rsupporting the vehicle body12. Although not particularly limited, the vehicle body12is constituted primarily of metal. A passenger compartment and a luggage compartment are defined within the vehicle body12. Each of the plurality of wheels14f,14ris rotatably attached to the vehicle body12. The plurality of wheels14f,14rincludes a pair of front wheels14fand a pair of rear wheels14r. The number of the wheels14f,14ris not limited to four.

The vehicle body12includes a traction motor16, a battery pack18, a PCU (Power Control Unit)20, and a vehicle ECU (Electronic Control Unit)22. The traction motor16is configured to drive at least one of the wheels14f,14r(e.g., the pair of rear wheels14r). The battery pack18is connected to the traction motor16via the PCU20.

The PCU20includes, for example, a power converter (not shown) such as a DC-DC converter and/or an inverter, and is configured to control electric power supplied from the battery pack18to the traction motor16. The traction motor16, the battery pack18, and the PCU20are so-called high-voltage components, which are electric components that operate at an AC voltage exceeding 30 volts or a DC voltage exceeding 60 volts.

The vehicle ECU22is a low-voltage component and is mounted in a relatively rear portion of the electric powered vehicle10. The vehicle ECU22is communicably connected to each of ECUs that control the traction motor16mounted on the electric powered vehicle10and components such as the battery pack18to be described later. Although not particularly limited, a serial communication protocol such as CAN (Controller Area Network) is employed in communication between the plurality of ECUs including the vehicle ECU22in the electric powered vehicle10according to the present embodiment. The vehicle ECU22includes a processor and a memory (not shown). The processor of the vehicle ECU22is configured to execute various types of control including instructions to the respective ECUs based on a program stored in advance in the memory and information from the respective ECUs and sensors.

The battery pack18is arranged along a floor of the vehicle body12. As shown inFIG.2, the battery pack18includes a battery casing19, a battery stack24, and a battery ECU26. The battery casing19has a box-like shape, in which the battery stack24and the battery ECU26are housed. The battery stack24includes a plurality of battery cells25and is configured to be charged and discharged repeatedly. Typically, the battery stack24is charged with electric power supplied from an external power source (e.g., a charging station). The battery stack24is connected to the traction motor16via the PCU20and is configured to supply electric power to the traction motor16. The battery stack24is also configured to be charged, via the PCU20, with regenerative electric power generated in the traction motor16.

As described, the battery ECU26is communicably connected to the vehicle ECU22. However, the communication between the vehicle ECU22and the battery ECU26may be unintentionally disrupted due to, for example, a physical abnormality in a communication circuit. In this case, the battery ECU26needs to be able to promptly detect such communication disruption and take necessary actions such as prohibiting or limiting discharge of the battery stack24. In order to do so, in the electric powered vehicle10according to the present embodiment, the vehicle ECU22sends first identification data D1and second identification data D2to the battery ECU26, for example, at predetermined intervals. The battery ECU26recognizes that it can communicate with the vehicle ECU22by receiving the first identification data D1and the second identification data D2. In order to detect a communication disruption between the two ECUs22and26, normally use of only single piece of identification data is sufficient, and use of the two pieces of identification data D1and D2is not necessarily needed. However, in the electric powered vehicle10according to the present embodiment, the two pieces of identification data D1, D2are used on the assumption that the battery pack18may be reused. This will be described later in detail.

When the battery ECU26recognizes that it can communicate with the vehicle ECU22, the battery ECU26executes a predetermined mutual monitoring function for the vehicle ECU22. Thereby, when something abnormal occurs in the operation of the battery ECU26, for example, the abnormality can be immediately detected by the vehicle ECU22. Similarly, when something abnormal occurs in the operation of the vehicle ECU22, the abnormality can be immediately detected by the battery ECU26. Particularities of the mutual monitoring function are not particularly limited. For example, the battery ECU26may send a predetermined request signal to the vehicle ECU22. When receiving the request signal, the vehicle ECU22may send an answer signal corresponding to the request signal to the battery ECU26. Then, the battery ECU26may determine that the vehicle ECU22is operating normally by receiving the answer signal. If, for example, an abnormality is detected in the vehicle ECU22as a result of the mutual monitoring function having been executed, the battery ECU26executes a fail-safe operation corresponding to the abnormality. An example of this fail-safe operation is an operation to prohibit or limit charging and discharging of the battery stack24, although not particularly limited thereto.

The battery pack18in the present embodiment is expected to be reused as a power source, for example, in a facility or store. However, reusing the battery pack18for the electric powered vehicle10, as it is, in another application requires an ECU of a battery-pack reusing system to also have the sophisticated mutual monitoring function of the battery ECU26. However, in the facility or store where the battery pack18is expected to be reused, a fail-safe design equivalent to that of the electric powered vehicle10is not required typically. Thus, providing the mutual monitoring function to the ECU of the battery-pack reusing system, just to match the battery ECU26, could bring an unnecessary cost increase.

In view of this, in the electric powered vehicle10according to the present embodiment, the battery ECU26determines that it is communicably connected to another ECU other than the vehicle ECU22when it receives the first identification data D1but does not receive the second identification data D2, and disables the aforementioned mutual monitoring function for the vehicle ECU22. That is, even when the second identification data D2cannot be received, the battery ECU26operates as usual, although it disables the mutual monitoring function, so long as it receives the first identification data D1. According to such a configuration, it is sufficient to provide a function of sending the first identification data D1in the ECU of the battery-pack reusing system, and there is no need to provide the mutual monitoring function therein, as in the vehicle ECU22. When the battery pack18is applied in the battery-pack reusing system, the battery ECU26can autonomously recognize the change in application and stop the mutual monitoring function which is unnecessary therein. Thus, a special modification to the battery pack18is not required to apply the battery pack18in the battery-pack reusing system, and thereby the reuse of the battery pack18in another application can be facilitated.

FIG.3shows a series of processes executed by the battery ECU26. By executing the series of processes shown inFIG.3, the battery ECU26enables the mutual monitoring function while mounted on the electric powered vehicle10and disables the mutual monitoring function after applied to the battery-pack reusing system. Hereinbelow, the series of processes shown inFIG.3will be described, however, this is merely an example and does not place any limitation on the configuration of the battery ECU26.

In step S12, the battery ECU26determines whether it has received the first identification data D1or not. If the battery ECU26has received the first identification data D1(YES in S12), the battery ECU26proceeds to a process of step S14. If the battery ECU26has not received the first identification data D1(NO in S12), the battery ECU26proceeds to a process of step S36.

In step S14, the battery ECU26determines whether it has received the second identification data D2or not. If the ECU26has received the second identification data D2(YES in S14), the battery ECU26determines that it is communicably connected to the vehicle ECU22(step S16) and enables the mutual monitoring function for the vehicle ECU22(step S18).

If the battery ECU26has not received the second identification data D2(NO in S14), the battery ECU26determines that it is communicably connected to the ECU of the battery-pack reusing system (step S26) and disables the mutual monitoring function for the vehicle ECU22(step S28).

If proceeding from step S12to the process of step S36, the battery ECU26determines that communication with the communication counterpart ECU is disrupted and executes the fail-safe operation (step S38). When the series of processes of steps S12to S38has been completed, the battery ECU26returns to step S12.

As above, according to the series of processes shown inFIG.3, the battery pack18can execute the mutual monitoring function required between the battery ECU26and the vehicle ECU22while it is mounted on the electric powered vehicle10. On the other hand, when the battery pack18is applied in the battery-pack reusing system, the battery ECU26can autonomously recognize the change in application and stop the mutual monitoring function which is unnecessary therein. In order to make the above determination, the battery ECU26uses both the first identification data D1and the second identification data D2as identification data for detecting a communication disruption. The first identification data D1is common identification data that is used in both the electric powered vehicle10and the battery-pack reusing system. The second identification data D2is vehicle-dedicated identification data that is used solely in the electric powered vehicle10. Using these pieces of identification data in combination enables the battery pack18for the electric powered vehicle10to be reused in another application, and thus vehicle electrification can be promoted.