Straddled vehicle-battery pack and straddled vehicle

Abstract

The purpose of the present invention is to provide a straddled vehicle battery pack capable of being reduced in size by a simple configuration and capable of being charged in a short time. A straddled vehicle battery pack (1) is provided with: a plurality of lithium-ion batteries (11); a case (12) for housing the plurality of lithium-ion batteries; and an electrical connection connector (13) connected to a mating connector provided on the vehicle body of a straddled vehicle (100) and transferring current that is input to and output from the vehicle body. The straddled vehicle battery pack has a charge capacity of 2.5Ah or more, a maximum charge voltage of 12V to 60V, inclusive, and a non-parallel series connection structure of the plurality of lithium-ion batteries each having a continuous maximum charge rate of 10C or more so that electric power converted to motive power and used for increasing the drive force of the straddled vehicle is received and output, wherein said maximum charge voltage is a voltage corresponding to the voltage across both ends of the series connection.

Description

DESCRIPTION Title of Invention STRADDLED VEHICLE-BATTERY PACK AND STRADDLED VEHICLE Technical Field

[0001] The present teaching relates to a straddled vehicle-battery pack, and a straddled vehicle. Background Art

[0002] Abattery pack for use in a straddled vehicle is disclosed for example, in Patent Literature 1 (PTL 1). The straddled vehicle of PTL 1 is a vehicle having no engine. PTL 1 illustrates an electric motorcycle as an example of the straddled vehicle. The battery pack of PTL 1 is installed in a straddled vehicle. The battery pack of PTL 1 includes plural casings for accommodating battery units. A heat dissipation space is formed between some of the plural casings. This is how the technique of PTL 1 attempts to increase the heat dissipation ability of the battery pack while the battery pack retains a great amount of energy capacity. Citation List Patent Literature

[0003] PTL 1: Japanese Patent Application Laid-Open No. 2013-232280 Summary of Invention Technical Problem

[0004] It is desired that a straddled vehicle-battery pack for use in a straddled vehicle be downsized with a simple configuration, for the purpose of improving mountability to the vehicle. It is also desired that a straddled vehicle-battery pack for use in a straddled vehicle be capable of being charged with electricity within a short amount of time, the electricity being adequate to increase a driving force of the straddled vehicle.

[0005] The present teaching aims to provide a straddled vehicle-battery pack capable of being downsized with a simple configuration, and capable of being charged with electricity within a short amount of time, the electricity being adequate to increase a driving force of a straddled vehicle. Solution to the Problem

[0006] The present inventor examined characteristics of a straddled vehicle battery pack for use in a straddled vehicle, and suitable for a straddled vehicle. It is desired that a straddled vehicle-battery pack be capable of charging within a short amount of time in circumstances different to those of battery packs that are used in other devices. For example, Japanese Patent Application Laid-Open No. 2007-052968 shows a battery pack for a mobile phone or the like. A straddled vehicle is normally able to travel with a rider riding on it at a speed similar to that of an automobile. The straddled vehicle is driven with a driving force outputted from a power source. The straddled vehicle includes a motor, for example. The motor converts electricity charged in a straddled vehicle-battery pack, into motive power. Electricity for increasing the driving force of the straddled vehicle is significantly different in magnitude than electricity consumed by a mobile phone or the like. A charge capacity of the straddled vehicle-battery pack is significantly different in magnitude than a charge capacity of a battery pack for a mobile phone or the like. It is desired for a straddled vehicle-battery pack to have a large charge capacity, and to be capable of charging within a short amount of time.

[0007] A straddled vehicle is configured such that the vehicle posture is controlled by a rider’s weight-shifting when traveling. Abattery module for an EV forklift is disclosed for example, in Japanese Patent Application Laid-Open No. 2014-180185. The forklift is a vehicle primarily intended to lift and carry heavy objects. The forklift is not configured such that the vehicle posture is controlled by a rider’s weight-shifting. The forklift is weighted such that a weight balance can be kept when carrying a heavy object. As for the straddled vehicle, on the other hand, there tends to be a desire for downsizing, from the viewpoint of the maneuverability and travel performance mentioned above. The weight ratio of a straddled vehicle-battery pack to the entire straddled vehicle is higher than those of the other components mounted. A straddled vehicle-battery pack for use in a straddled vehicle is required to be small in size while being capable of receiving and outputting electricity for increasing a driving force.

[0008] As a result of studies on a straddled vehicle-battery pack having such characteristics, the present inventor discovered the followings.

[0009] Normally in a battery pack, plural batteries are used in combination, for the purpose of providing a great amount of energy capacity or charge capacity. For example, the battery pack of PTL 1 includes plural batteries. For example, in PTL 1, 168 batteries for instance are connected in parallel and in series, to provide an increased amount of energy capacity. In more detail, 12 batteries that are connected in parallel form one group, and 14 groups are connected in series. The battery pack of PTL 1 includes a control section. The control section is a battery management controller (BMC) having a CPU and a memory. The control section is connected, by electric wire, to each of the batteries included in the battery pack. The control section monitors a state of each battery. The control section centralizes the controlling of each battery. In other words, information representing a state of each battery is collected from the battery to the control section. Based on the collected information, the control section controls each battery. More specifically, the control section, which is connected to each battery and has the CPU and the memory, detects the temperature, the electric current, the voltage, the frequency of use, and the like, of each battery, and thus centralizes and monitors the state of each battery, and also controls each battery.

[0010] In the battery pack of PTL 1, 12 batteries that form one group are connected in parallel. The batteries connected in parallel show variations in their characteristics including an internal resistance, due to the state of an electrode and the state of an electrolyte. When charging, equal voltages are applied to the batteries connected in parallel. However, electric currents flowing through the batteries connected in parallel depend on the variations in characteristics. To be precise, therefore, charging amounts of the batteries connected in parallel differ depending on the variations in characteristics. The control section controls, by detecting the state of each battery, the charging amount of a battery that is likely to have a different charging amount because of the parallel connection.

[0011] The present inventor examined various configurations of a straddled vehicle-battery pack suitable for a straddled vehicle. In the examination by the present inventor, a charging voltage of the straddled vehicle-battery pack was set to 12 V or more and 60 V or less while plural lithium ion batteries were purposely connected in series instead of in parallel with one another. Also in the examination by the present inventor, a straddled vehicle-battery pack having a charge capacity of 2.5 Ah or more was constituted by lithium ion batteries having a maximum continuous charge rate of 10 C or more. The present inventor discovered that this configuration allows the straddled vehicle-battery pack to be downsized with a simple configuration so that it can be charged within a short amount of time. Since the charging voltage of the straddled vehicle-battery pack having a charge capacity of 2.5 Ah or more is set to 12 V or more, the straddled vehicle-battery pack is capable of charging electricity adequate to increase the driving force of the straddled vehicle. If such a straddled vehicle-battery pack is constituted of lithium ion batteries having a maximum continuous charge rate of 10 C or more, it is possible for the straddled vehicle-battery pack to have a maximum continuous charge rate of 10 C or more even though the plural lithium ion batteries are connected in series without any parallel connection.

[0012] When plural lithium ion batteries are not connected in parallel but connected in series with one another, electric currents flowing through the respective lithium ion batteries at a time of charging are substantially equal. That is, the electric currents flowing through the respective lithium ion batteries are substantially equal irrespective of an internal resistance of each lithium battery. It therefore is easy to keep a balance between charging amounts of the respective lithium ion batteries. Accordingly, for example, a circuit that manages an electric current, a voltage, or a temperature of each lithium ion battery can be simplified or eliminated. For example, it is possible to keep a balance between charging amounts of the respective lithium ion batteries, without a control device for monitoring and controlling states of lithium ion batteries connected in parallel. Consequently, a straddled vehicle-battery pack having a simple configuration and being small in size can be achieved.

[0013] In the configuration, the plural lithium ion batteries are not connected in parallel but connected in series with one another, while the maximum voltage that the straddled vehicle-battery pack can charge is 20 V or more and 60 V or less. In this case, the maximum voltage applied across the plural lithium ion batteries connected in series is 60 V or less. Thus, the straddled vehicle-battery pack operates in a range that belongs to “extra low voltage (ELV)” or “safety extra low voltage (SELV)” according to the IEC (International Electrotechnical Commission) standard No. IEC60950. Since the voltage of the straddled vehicle-battery pack is a low voltage, its insulation structure can be simpler than that of a high-voltage one.

[0014] As mentioned above, the voltage applied across the plural lithium ion batteries connected in series is a low voltage belonging to the “extra low voltage”. In this case, the number of lithium ion batteries connected in series can be reduced as compared to a case of, for example, belonging to a voltage range higher than a voltage belonging to the “extra low voltage”. As a result, variations in charging ability characteristics between the respective lithium ion batteries included in the straddled vehicle-battery pack can be reduced as compared to a case of, for example, using many lithium ion batteries for adaptation to high voltages. This allows simplification or elimination of the monitoring and controlling circuit. Accordingly, a straddled vehicle-battery pack having a simple configuration and being small in size can be achieved.

[0015] Since each of the plural lithium ion batteries connected in series has a maximum continuous charge rate of 10 C or more, it is possible for the straddled vehicle-battery pack to obtain a maximum continuous charge rate of 10 C or more, without any parallel connection of the plural lithium ion batteries. The straddled vehicle-battery pack having a maximum continuous charge rate of 10 C or more allows, for example, 50% or more of the charge capacity of the straddled vehicle-battery pack to be charged within a short amount of time, that is, within three minutes. This makes it possible that, for example, an electric motor vehicle equipped with the straddled vehicle-battery pack is charged in a time length near that required for replenishment of a liquid fuel at a conventional or existing gas station. A lengthy occupancy at a charge station is therefore not necessary.

[0016] In this manner, eliminating parallel connection makes it possible to keep a balance between charging amounts of the respective lithium ion batteries, without any control device for monitoring and controlling states of lithium ion batteries connected in parallel. It is also possible to simplify the insulation structure. It is possible for a straddled vehicle-battery pack to have a simple configuration and to be small in size. It is possible to charge the straddled vehicle-battery pack within a short amount of time, because the straddled vehicle-battery pack can achieve a maximum charge rate of 10 C or more without any parallel connection of the plural lithium ion batteries. Accordingly, a straddled vehicle-battery pack having a simple configuration and being small in size, and being capable of charging electricity within a short amount of time can be made possible, the electricity being adequate to increase a driving force of a straddled vehicle.

[0017] A straddled vehicle-battery pack according to aspects of the present teaching, which is accomplished based on the above-described knowledge, has the following configurations.

[0018] (1) A straddled vehicle-battery pack for use in a straddled vehicle, the straddled vehicle-battery pack including: plural lithium ion batteries; a casing that accommodates the plural lithium ion batteries; and an electrical connector connected to a mating connector disposed in a vehicle body of the straddled vehicle, the electrical connector being configured to transmit electric current received and outputted, to the vehicle body, the straddled vehicle-battery pack having a charge capacity of 2.5 Ah or more, a maximum charging voltage of 12 V or more and 60 V or less, and a series-connection structure in which the plural lithium ion batteries each having a maximum continuous charge rate of 10 C or more are connected in series without any parallel connection, to be able to receive and output electricity that is to be converted into motive power for increasing a driving force of the straddled vehicle, the maximum charging voltage being a voltage corresponding to a voltage across the series connection.

[0019] In the foregoing configuration, the straddled vehicle-battery pack includes the plural lithium ion batteries. The straddled vehicle-battery pack has a charge capacity of 2.5 Ah or more, a maximum charging voltage of 12 V or more and 60 V or less, and the series-connection structure in which the plural lithium ion batteries are connected in series without any parallel connection. Each of the plural lithium ion batteries has a maximum continuous charge rate of 10 C or more. Here, 12 V is the lower limit of an operating voltage widely used as a voltage of a power source that contributes to increasing a driving force of a straddled vehicle. The charge capacity of 2.5 Ah or more is a capacity of electricity capable of increasing a driving force of a straddled vehicle, unlike a capacity for operating a low-power device such as a mobile phone. By being charged with a maximum charging voltage of 12 V or more and 60 V or less, the straddled vehicle-battery pack having a charge capacity of 2.5 Ah or more receives and outputs electricity adequate to increase the driving force of the straddled vehicle. Since each of the plural lithium ion batteries connected in series has a maximum continuous charge rate of 10 C or more, the straddled vehicle-battery pack can achieve a maximum continuous charge rate of 10 C or more. The straddled vehicle-battery pack having a maximum continuous charge rate of 10 C or more allows 50% or more of the charge capacity of the straddled vehicle- battery pack to be charged within three minutes, for example. Accordingly, electricity for increasing the driving force of the straddled vehicle can be charged within a short amount of time.

[0020] Since each of the lithium ion batteries has a maximum continuous charge rate of 10 C or more, the straddled vehicle-battery pack having a maximum continuous charge rate of 10 C or more can be achieved with a configuration in which the plural lithium ion batteries are not connected in parallel. In a case of plural lithium ion batteries connected in parallel for example, electric currents flowing in the respective lithium ion batteries connected in parallel at a time of charging vary depending on internal resistances of the respective lithium ion batteries. As a result, the lithium ion batteries have different charging amounts. In a structure of plural lithium ion batteries connected in series without any parallel connection, electric currents that are being received by the respective lithium ion batteries at a time of charging are substantially equal. It therefore is easy to keep a balance between charging amounts of the respective lithium ion batteries. Accordingly, it is possible to keep a balance between charging amounts of the respective lithium ion batteries, without a control device for monitoring and controlling states of lithium ion batteries connected in parallel. Consequently, a straddled vehicle-battery pack having a simple configuration and being small in size can be made possible.

[0021] In the configuration, the plural lithium ion batteries are not connected in parallel but connected in series with one another, while the maximum voltage that the straddled vehicle-battery pack can charge is 20 V or more and 60 V or less. In this case, the maximum voltage that can be applied across the plural lithium ion batteries connected in series is 60 V or less. Thus, the straddled vehicle-battery pack operates in a range that is referred to as “extra-low voltage” (extra-low voltage: ELV, or safety extra-low voltage: SELV) according to the IEC (International Electrotechnical Commission) standard No. IEC60950. Since the voltage of the straddled vehicle-battery pack is a low voltage, its insulation structure can be simpler than that of a high-voltage one. Accordingly, the straddled vehicle-battery pack can be downsized.

[0022] As mentioned above, the voltage applied across the plural lithium ion batteries connected in series is a low voltage referred to as the “extra-low voltage”. In this case, the number of lithium ion batteries connected in series can be reduced as compared to a case of, for example, being in a voltage range higher than a voltage being referred to as the “extra-low voltage”. As a result, variations in charging ability characteristics between the respective lithium ion batteries included in the straddled vehicle-battery pack can be reduced as compared to a case of, for example, using many lithium ion batteries for adaptation to high voltages. This also allows simplification or elimination of the monitoring and controlling circuit. Accordingly, the straddled vehicle- battery pack having a simple configuration and being small in size can be achieved.

[0023] In this manner, the straddled vehicle-battery pack, having a charge capacity of 2.5 Ah or more and a maximum charging voltage of 12 V or more and 60 V or less, is able to charge electricity adapted to the driving force of the straddled vehicle. Since the straddled vehicle-battery pack is configured with a series connection of the lithium ion batteries each having a maximum continuous charge rate of 10 C or more, the straddled vehicle-battery pack is able to charge electricity adapted to the driving force of the straddled vehicle within a short amount of time. Since each of the plural lithium ion batteries has a maximum continuous charge rate of 10 C or more, a series-connection structure having no parallel connection can be employed. Elimination of parallel connection allows simplification or elimination of a circuit for monitoring each lithium ion battery. The maximum charging voltage of 12 V or more and 60 V or less can also make way for a simpler insulation structure. Accordingly, a straddled vehicle-battery pack having a simple configuration and being small in size, and being capable of charging electricity adequate to increase a driving force of a straddled vehicle within a short amount of time, can be made possible.

[0024] In an aspect of the present teaching, the straddled vehicle-battery pack may have the following configuration.

[0025] (2) In the straddled vehicle-battery pack according to (1), each of the plural lithium ion batteries has an independent negative electrode, the independent negative electrode containing at least any one selected from the group consisting of a spinel structure lithium titanate, a niobium-titanium-containing composite oxide, and graphite, and the independent negative electrode being connected to a positive electrode or a negative electrode without being electrically connected to another independent negative electrode, to provide a series-connection structure in which the plural lithium ion batteries are connected in series without any parallel connection.

[0026] In the foregoing configuration, each of the plural lithium ion batteries has an independent negative electrode. The structure having no parallel connection makes the negative electrodes electrically independent of one another. Each of the negative electrodes is not electrically connected to any other independent negative electrode. Each of these negative electrodes contains at least any one selected from the group consisting of a spinel structure lithium titanate, a niobium-titanium-containing composite oxide, and graphite. A negative electrode containing at least any one selected from the group consisting of a spinel structure lithium titanate, a niobium-titanium-containing composite oxide, and graphite can reduce the likelihood of occurrence of internal short-circuiting, which may otherwise be caused by deposition of lithium in a negative electrode as described in Japanese Patent Application Laid-Open No. 2015-153719, for example. The plural lithium ion batteries each having such a negative electrode are connected so as to avoid electrical connection between the negative electrodes, and thus a circuit for monitoring each lithium ion battery can be further simplified or eliminated even with a configuration that performs charging at a maximum continuous charge rate of 10 C or more. Accordingly, a straddled vehicle-battery pack having a simpler configuration and being small in size can be made possible.

[0027] In an aspect of the present teaching, the straddled vehicle-battery pack may have the following configuration. (3) The straddled vehicle-battery pack according to (1) or (2) further includes an electric current breaker that breaks an electric current flowing through the plural lithium ion batteries, the electric current breaker being connected in series with the plural lithium ion batteries.

[0028] The foregoing configuration can suppress unintentional flow-out of the electric current of the plural lithium ion batteries to the outside through the electrical connector. It therefore is possible to suppress the following situation: during an operation of detaching or attaching the straddled vehicle-battery pack from or to the vehicle body for example, the electrical connector is unintentionally in contact with a conductor of some kind at a location outside the straddled vehicle-battery pack, and as a result, a large electric current caused by short-circuiting welds the conductor to the electrical connector. Accordingly, the likeliness that a situation whereby, for example, the external conductor becomes welded to the electrical connector can be suppressed with a simple configuration of the control device being simplified or eliminated.

[0029] In an aspect of the present teaching, the straddled vehicle-battery pack may have the following configuration. (4) In the straddled vehicle-battery pack according to any one of (1) to (3), the straddled vehicle-battery pack is configured without inclusion of any control device configured to acquire at least one parameter from among an electric current, a voltage, or a temperature detected from each of the plural lithium ion batteries, and based on the at least one parameter acquired, to change a voltage and / or an electric current of at least one lithium ion battery of the plural lithium ion batteries.

[0030] In the foregoing configuration, the plural lithium ion batteries each having a maximum continuous charge rate of 10 C or more are connected in series without any parallel connection, and the maximum charging voltage of the straddled vehicle-battery pack corresponding to the voltage across the series connection is 60 V or less. Since the plural lithium ion batteries are not connected in parallel, the foregoing configuration makes it possible to keep a balance between charging amounts of the respective lithium ion batteries, while omitting the control device mentioned above. Accordingly, a straddled vehicle- battery pack having a simple configuration, being small in size, and being capable of charging within a short amount of time can be made possible.

[0031] In an aspect of the present teaching, the straddled vehicle-battery pack may have the following configuration. (5) A straddled vehicle includes: the straddled vehicle-battery pack according to any one of (1) to (4); a mating connector configured to be connected to the electrical connector of the straddled vehicle-battery pack; a driving wheel; a motor control device configured to control a supply of electricity from the straddled vehicle-battery pack to a motor via the mating connector and a supply of electricity from the motor to the straddled vehicle-battery pack via the mating connector; and the motor configured to drive the driving wheel with electricity supplied from the motor control device as well as to generate electricity by the driving wheel being driven, wherein the straddled vehicle is configured without inclusion of any control device that is configured to acquire at least one parameter from among an electric current, a voltage, or a temperature detected from each of the plural lithium ion batteries, and based on the at least one parameter acquired, change a voltage and / or an electric current of at least one lithium ion battery of the plural lithium ion batteries.

[0032] With the foregoing configuration, a straddled vehicle having a simple configuration and being small in size, and being capable of charging the battery pack within a short amount of time can be made possible.

[0033] In an aspect of the present teaching, the straddled vehicle may have the following configuration. (6) The straddled vehicle according to (5) further includes: a handle bar for steering, disposed so as to extend in the left-right direction of the straddled vehicle; and a saddle configured to have a rider sit straddling thereon, the straddled vehicle being configured, as a lean vehicle, to make a turn in such a manner that at a time of turning, a rider who grips the handle bar shifts their weight so as to make the straddled vehicle lean toward the inside of 3 curve.

[0034] For a straddled vehicle as a lean vehicle, the lightness and responsiveness in response to a rider’s manipulation are important, and thus downsizing is highly desired. The straddled vehicle, however, is equipped with a straddled vehicle-battery pack. This is why achieving a high level of responsiveness and lightness has been desired in a straddled vehicle as a lean vehicle. The foregoing configuration can provide a straddled vehicle as a lean vehicle having good responsiveness and lightness, capable of being downsized with a simple configuration, and capable of charging a battery pack within a short amount of time.

[0035] An increase in the driving force of the straddled vehicle can be made possible by using electricity stored in the straddled vehicle-battery pack. The term “electricity” as used herein encompasses at least chemical energy stored in a secondary battery pack, for example. In an exemplary configuration, the straddled vehicle may include a capacitor, too, and may travel not only with chemical energy but also with electrophysical energy stored in the capacitor. The straddled vehicle can be a vehicle having no engine, for example. The straddled vehicle can be a pure electric straddled vehicle, for example. The straddled vehicle, however, is not limited to the above, and may be a vehicle equipped with an engine as an internal combustion engine. For example, a plug-in hybrid vehicle having a function of charging with electricity supplied from the outside of the vehicle and capable of traveling also with an engine installed in the vehicle is encompassed by the straddled vehicle.

[0036] When the straddled vehicle travels, the straddled vehicle-battery pack is charged with electricity generated by the motor being driven by the driving wheel. The straddled vehicle-battery pack is connected to a charging apparatus disposed outside the straddled vehicle, to be charged. In a case where the straddled vehicle-battery pack is used in a straddled vehicle equipped with an engine, the straddled vehicle-battery pack is charged with electricity of a generator driven by the engine.

[0037] The straddled vehicle is a vehicle for riding in a riding style upon a saddle. A rider sits with legs astride a saddle of the straddled vehicle. The straddled vehicle is a lean vehicle, for example. Examples of the straddled vehicle include a scooter-type motorcycle, a moped-type motorcycle, an offroad- type motorcycle, and an on-road-type motorcycle. The straddled vehicle is not limited to a motorcycle, and may be an all-terrain vehicle (ATV) or the like, or may be a three-wheeled motorcycle, for example. The three-wheeled motorcycle may have two front wheels and one rear wheel, or may have one front wheel and two rear wheels.

[0038] The straddled vehicle-battery pack is a battery pack for use in a straddled vehicle. The straddled vehicle-battery pack is a pack having plural lithium ion batteries combined and integrated. The straddled vehicle-battery pack is mounted to a vehicle body of the straddled vehicle. The straddled vehicle-battery pack can be mounted to the vehicle body in a non-replaceable manner, for example.

[0039] The straddled vehicle-battery pack is not particularly limited, and for example, may be mounted to the vehicle body in a replaceable manner. The straddled vehicle-battery pack may be removed from the vehicle body without using a tool different from a key, such as a spanner, or may be replaceable in relation to the vehicle body by using a tool different from a key, such as a spanner.

[0040] The lithium ion battery is a battery capable of charging and discharging. The lithium ion battery can be a secondary battery that performs charging and discharging through a chemical reaction on electrodes. The lithium ion battery performs charging and discharging through oxidation and reduction reactions on electrodes. The lithium ion battery converts chemical energy stored therein, into electrical energy. The lithium ion battery has its terminal voltage not in proportion to the amount of electricity stored in the battery. For example, a lithium ion capacitor is not encompassed by the lithium ion battery. The lithium ion battery has a positive electrode containing a lithium oxide. Alithium battery having a positive electrode containing a lithium metal is not encompassed by the lithium ion battery. The lithium ion battery is a non- aqueous lithium ion battery using a non-aqueous electrolyte such as an organic solvent. The lithium ion battery can be a battery capable of storing electricity for driving the motor of the straddled vehicle. The lithium ion battery is capable of storing electricity supplied from the outside of the straddled vehicle. The lithium ion battery can be capable of storing electricity supplied from the motor in a case where the motor of the straddled vehicle generates electricity. In other words, the lithium ion battery can be capable of storing a regenerated electric current of the motor.

[0041] The maximum charge rate refers to the highest maximum charge rate that can be obtained to the lithium ion battery or the straddled vehicle-battery pack. The maximum charge rate represents the speed of charging. The unit is C. The maximum continuous charge rate refers to the highest maximum charge rate that can be obtained in a case of continuous charging instead of instantaneous charging. In a case of continuous charging, that is, in a case of measurement of constant electric current charging, the magnitude of an electric current capable of completely charging the capacity of a battery in one hour is defined as 1 C. For example, 1 C is 2.5 A when the capacity of the battery is 25 Ah.

[0042] The capacity or charge capacity of a battery is the amount of electricity that can be charged in the battery. The unit is Ah. The charge capacity is equal to the discharge capacity. The discharge capacity is, for example, the amount of electric current accumulated over time, the electric currents being outputted from when a full-charged battery starts outputting an electric current with outputting an initial voltage to when its output voltage reaches a final voltage. Discharge conditions are that the electric current must be discharged such that the final voltage is reached by ten-hours discharging, for example (ten hour rate). The straddled vehicle-battery pack is configured by series connection of lithium ion batteries. Therefore, a discharging voltage, which is a condition of the discharge capacity, varies depending on the number of lithium ion batteries included in the straddled vehicle-battery pack. The discharge capacity is set regardless of the number of lithium ion batteries. The straddled vehicle-battery pack having a charge capacity of 2.5 Ah or more can charge or discharge electricity adequate to increase the driving force of the straddled vehicle. For example, in a case of a straddled vehicle-battery pack 1 having an output voltage of 12 V and a charge capacity of 2.5 Ah, outputting an electric current of 50 A for 20 seconds corresponds to an electricity consumption of about 10%. As a result of this consumption, the driving force can be assisted by about 600 W, or simply about 0.8 ps, for 20 seconds. The charge capacity of 2.5 Ah or more is at such a capacity level that by using 50% of the charge capacity, an increase of the driving force for 20 seconds can be continuously made five times at least without need of recharge. The straddled vehicle-battery pack having a charge capacity of 2.5 Ah or more, for example, is smaller in size than a device for charging electrophysical energy such as a capacitor.

[0043] The electrical connector transmits electric current received from and outputted to components of the vehicle body. For example, the electrical connector transmits an electric current that is outputted toward the motor of the straddled vehicle. For example, the electrical connector transmits an electric current that is supplied from the motor in a case where the motor of the straddled vehicle generates electricity. The electrical connector can be used as a connector for transmitting an electric current that is supplied from the outside of the straddled vehicle. Alternatively, the electrical connector may be provided as a connector different from the connector for transmitting an electric current that is supplied from the outside of the straddled vehicle.

[0044] The electrical connector is attached to the casing, for example. The electrical connector is supported by the casing, for example. The electrical connector is fixed to the casing, for example. The electrical connector, however, is not limited to the above, and may be supported by the casing in a swingable manner so that it can easily be connected to a mating connector, for example. The electrical connector may be connected to a cable that extends through the casing to the outside of the casing, for example. That is, the electrical connector may be physically connected to the casing via the cable without being supported by the casing. That is, the electrical connector may not need to be attached to the casing, for example.

[0045] Connection encompasses a state where an electrical component is interposed in the connection. Examples of the electrical component include a switch, an electric current breaker, a resistor, a connection terminal, and a fuse. Connection is made by wiring of a lead wire, for example. The wiring does not always have to include a single lead wire, but may be composed of two or more connected lead wires. The wiring may be a metal plate or rod, for example. The wiring may be a metal plate or rod having a bent portion or a curved portion, for example.

[0046] The straddled vehicle-battery pack receives and outputs electricity that is to be converted into motive power in order to increase the driving force of the straddled vehicle. This means that electricity that the straddled vehicle-battery pack outputs at a time of discharging is converted into motive power that contributes to increasing the driving force of the straddled vehicle. The electricity is converted into motive power by, for example, a motor. The motive power obtained by conversion is finally transmitted to a wheel. For example, the straddled vehicle can be a pure electric motor vehicle that travels with electricity charged mainly in the straddled vehicle-battery pack. An increase of the driving force of the straddled vehicle depends on electricity charged in the straddled vehicle-battery pack. The straddled vehicle, however, is not particularly limited to the above, and may have an engine as an internal combustion engine. For example, it may be possible that electricity is converted into motive power by a motor, and is used to drive the engine, to consequently increase the driving force of the straddled vehicle. For example, it may be possible for a generator to be provided to an engine, in order that both electricity charged in the straddled vehicle-battery pack and electricity produced by the generator, be supplied to a motor.

[0047] The electric current breaker is an electrical component capable of switching between a state of transmitting an electric current and a state of breaking an electric current. The electric current breaker is an electrical component that switches from the state of transmitting an electric current to the state of breaking an electric current in accordance with, for instance, the flow amount of an electric current. An Example of such an electric current breaker may include a fuse and a breaker. The electric current breaker is not particularly limited to the above, and may be an electrical component that switches from the state of transmitting an electric current to the state of breaking an electric current in accordance with, for instance, a rider’s manipulation. An example of such an electric current breaker may include a relay, a switch, a service plug.

[0048] The terminology used herein is for defining particular embodiments only and is not intended to be limiting the teaching. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. As used herein, the terms “including”, “comprising”, or “having”, and variations thereof specify the presence of stated features, steps, operations, elements, components, and / or equivalents thereof, and can include one or more of steps, operations, elements, components, and / or their groups. As used herein, the terms “attached”, “coupled”, and / or equivalents thereof are used in a broad sense, and include both of direct and indirect attachment and coupling unless otherwise specified. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present teaching belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the present disclosure and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. It will be understood that the description of the present teaching discloses a number of techniques and steps. Each of these has individual benefit and each can also be used in conjunction with one or more, or in some cases all, of the other disclosed techniques. Accordingly, for the sake of clarity, this description will refrain from repeating every possible combination of the individual steps in an unnecessary fashion. Nevertheless, Description and Claims should be read with the understanding that such combinations are entirely within the scope of the present teaching and the claims. Description will give an explanation about a novel straddled vehicle- battery pack. In the description given below, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present teaching. It will be apparent, however, that those skilled in the art may practice the present teaching without these specific details. The present disclosure is to be considered as an exemplification of the present teaching, and is not intended to limit the present teaching to the specific embodiments illustrated by drawings or descriptions below. Advantageous Effects of Invention

[0049] According to the present teaching, a straddled vehicle-battery pack capable of being downsized with a simple configuration, and capable of charging within a short amount of time can be achieved. Brief Description of Drawings

[0050] [FIG. 1] A diagram schematically showing a straddled vehicle-battery pack according to a first embodiment, a straddled vehicle equipped with the straddled vehicle-battery pack, and a comparative example. [FIG. 2] A diagram showing on a larger scale the straddled vehicle- battery pack according to the first embodiment shown in FIG. 1. [FIG. 3] A diagram more detailing the straddled vehicle shown in FIG. 1. [FIG. 4] A diagram schematically showing a straddled vehicle-battery pack according to a second embodiment. Description of Embodiments

[0051] In the following, embodiments will be described with reference to the drawings.

[0052] [First Embodiment] FIG. 1 is a diagram schematically showing a straddled vehicle-battery pack according to a first embodiment, a straddled vehicle equipped with the straddled vehicle-battery pack, and a comparative example. The part (a-1) of FIG. 1 schematically shows the straddled vehicle equipped with the straddled vehicle-battery pack according to the first embodiment. The part (b-1) of FIG. 1 schematically shows the straddled vehicle-battery pack according to the first embodiment. The part (a-2) of FIG. 1 schematically shows a straddled vehicle equipped with a straddled vehicle-battery pack according to the comparative example. The part (b-2) of FIG. 1 schematically shows the straddled vehicle- battery pack according to the comparative example. FIG. 2 is a diagram showing on a larger scale the straddled vehicle: battery pack according to the first embodiment shown in FIG. 1.

[0053] A straddled vehicle-battery pack 1 shown in the part (b-1) of FIG. 1is a battery pack for use in a straddled vehicle 100. The straddled vehicle-battery pack 1 receives and outputs electricity that is to be converted into motive power for increasing a driving force of the straddled vehicle 100. The straddled vehicle-battery pack 1 is a battery pack capable of charging and discharging. The straddled vehicle-battery pack 1 is charged with a voltage equal to or less than a maximum charging voltage. The maximum charging voltage of the straddled vehicle-battery pack 1 is 12 V or more and 60 V or less. The maximum charging voltage of the straddled vehicle-battery pack 1 is 48 V, for example. The maximum charging voltage may be set to 14 V for example, or may be set to 36 V for example. The straddled vehicle-battery pack 1 has a charge capacity of 2.5 Ah or more. The straddled vehicle-battery pack 1, therefore, receives and outputs electricity for increasing the driving force of the straddled vehicle 100.

[0054] The straddled vehicle-battery pack 1 includes lithium ion batteries 11, a casing 12, and an electrical connector 13.

[0055] In the example shown in the part (b-1) of FIG. 1, the straddled vehicle- battery pack 1 includes five lithium ion batteries 11. The lithium ion batteries 11 are not connected in parallel but connected in series with one another. The straddled vehicle-battery pack 1 is structured to connect the lithium ion batteries 11 in series without any parallel connection. The number of lithium ion batteries 11 is set such that a maximum voltage across the series connection can be equal to or more than the maximum voltage of the straddled vehicle-battery pack 1. The lithium ion battery 11 is a battery capable of charging and discharging. The lithium ion battery 11 is a secondary battery that performs charging and discharging through a chemical reaction on electrodes. The lithium ion battery 11 has a positive electrode containing a lithium oxide. The lithium ion battery 11 is a non-aqueous lithium ion battery using a non-aqueous electrolyte. The lithium ion battery 11 has a negative electrode containing at least any one selected from the group consisting of a spinel structure lithium titanate, a niobium-titanium-containing composite oxide, or graphite, for example. Here, the negative electrode of the lithium ion battery 11 is not particularly limited, and a negative electrode containing a substance other than the above may be adoptable. The lithium ion battery 11 has a maximum charging electric current higher than that of a battery whose positive electrode contains another material, such as a lead-acid battery or a nickel-metal hydride battery. The lithium ion battery 11 has a maximum continuous charge rate of 10 C or more.

[0056] The casing 12 accommodates the lithium ion batteries 11. The casing 12 has a closed structure, for example. Specifically, the casing 12 has a structure that makes the lithium ion batteries 11 invisible from the outside. This can suppress occurrence of a situation where the lithium ion batteries 11 are contacted by a foreign body put in from the outside of the straddled vehicle-battery pack 1. More specifically, the casing 12 has a waterproof structure, for example. In a case of the straddled vehicle-battery pack 1 being provided in the straddled vehicle 100 for example, the straddled vehicle-battery pack 1 may possibly be exposed to liquid such as water or oil. The casing 12 suppresses intrusion of the liquid. Accordingly, contact of the liquid with the lithium ion batteries 11 is suppressed.

[0057] The electrical connector 13, which is connected to a mating connector (not shown) disposed in a vehicle body 102 (see FIG. 3) of the straddled vehicle 100, transmits electric current received and outputted, to the vehicle body 102. Electricity stored in the straddled vehicle-battery pack 1 is supplied to the vehicle body 102 of the straddled vehicle 100 through the electrical connector 13. In regeneration, regenerated electricity is supplied from the vehicle body 102 of the straddled vehicle 100 to the straddled vehicle-battery pack 1 through the electrical connector 13. The electrical connector 13 of this embodiment can also be connected to a charging apparatus, such as a charge station, disposed outside the straddled vehicle 100. When the straddled vehicle 100 is stopped, a mating connector disposed in an external charging apparatus is connected, instead of the mating connector disposed in the vehicle body 102 (see FIG. 3). Thus, the straddled vehicle-battery pack 1 is charged.

[0058] The straddled vehicle-battery pack 1 includes bus bars 14, too. The bus bars 14 are conductors that connect the lithium ion batteries 11 and the electrical connector 13. The bus bars 14 connect the lithium ion batteries 11 to one another. The bus bars 14 connect the lithium ion batteries 11 and the electrical connector 13 in series.

[0059] The lithium ion batteries 11 included in the straddled vehicle-battery pack 1 of this embodiment are not connected in parallel but connected in series with one another. There are variations in internal resistance between the lithium ion batteries 11. However, electric currents flowing through the respective lithium ion batteries 11 connected in series are substantially equal irrespective of differences in internal resistance. It therefore is easy to keep a balance between charging amounts of the respective lithium ion batteries 11. For example, in a case where charging is started when the charging amount of each lithium ion battery 11 is zero, the accumulated amounts of electric currents in the respective lithium ion batteries 11 at an arbitrary time are substantially equal. That is, the charging amounts of the respective lithium ion batteries 11 are substantially equal. Also in discharging of the lithium ion batteries 11, substantially equal electric currents flow in the respective lithium ion batteries 11. Thus, the charging amounts of the respective lithium ion batteries 11 at an arbitrary time are substantially equal. In charging, therefore, the lithium ion batteries 11 reach a full charge state substantially at the same time. This makes it possible to keep a balance between charging amounts of the respective lithium ion batteries 11 without a control device for monitoring and controlling states of lithium ion batteries connected in parallel. Accordingly, the straddled vehicle-battery pack 1 can be downsized with a simple configuration. A standard working voltage of each lithium ion battery 11 is 2.3 V, for example. Each lithium ion battery 11 can be charged with a voltage higher than the standard working voltage, however. Each lithium ion battery 11 is charged with a voltage of 3 V or more, for example.

[0060] While the lithium ion batteries 11 are configured to be not connected in parallel but connected in series with each other, the maximum voltage that the straddled vehicle-battery pack 1 can charge is 12 V or more and 60 V or less. In this configuration, the maximum voltage applied across a group of the lithium ion batteries 11 connected in series is 12 V or more and 60 V or less.

[0061] Since the maximum voltage that the straddled vehicle-battery pack 1 can charge is 12 V or more, a design is allowed in which it is in direct electrical connection with an ordinary electrical component mounted to the straddled vehicle 100. Since the maximum voltage that the straddled vehicle-battery pack 1 can charge is 12 V or more, a design is allowed in which a motor 105 generally mounted to the straddled vehicle 100 is used as a motor 105 that receives a supply of charged electricity. Since the maximum voltage that the straddled vehicle-battery pack 1 can charge is 12 V or more, the motor 105 that receives a supply of charged electricity can easily increase the driving force of the straddled vehicle 100.

[0062] The straddled vehicle-battery pack 1 operates in a range that belongs to “extra low voltage” (extra low voltage: ELV, or safety extra low voltage: SELV) according to the IEC (International Electrotechnical Commission) standard No. IEC60950. A potential difference at any node within the straddled vehicle- battery pack 1 does not exceed 60 V. This is why the “operational insulation” range is enough as an insulation level of each node used in the battery pack. An insulation structure of the straddled vehicle-battery pack 1, whose voltage is a low voltage, can be simplified as compared to a high-voltage one.

[0063] As the lithium ion battery 11, for instance, a lithium ion battery 11 having a charge capacity of 5 Ah or more and 40 Ah or less is adoptable. In a case where such a lithium ion battery 11 has a maximum charging voltage of 3 V, the straddled vehicle-battery pack 1 including five lithium ion batteries 11 connected in series has a maximum charging voltage of 15 V. In a case where, for example, the lithium ion battery 11 has a charge capacity of 5 Ah and a maximum continuous charge rate of 10 C, the lithium ion battery 11 has a maximum continuous charging electric current of 50 A. In a case where, for example, the lithium ion battery 11 has a charge capacity of 20 Ah and a maximum continuous charge rate of 10 C, the lithium ion battery 11 has a maximum continuous charging electric current of 200 A. Thus, it is not easy to grasp the ability to full-charge a battery based only on the charging electric current. This is because the ability of the battery to reach full-charge varies depending not only on the charging electric current but also on the charge capacity. Inthe Description herein, therefore, an indication using a charge rate with a difference in charge capacity taken into account is employed to indicate the ability of the battery to reach full-charge.

[0064] As mentioned above, the voltage applied across the plural lithium ion batteries 11 connected in series is a low voltage belonging to the “extra low voltage”. In this case, the number of lithium ion batteries 11 connected in series can be reduced as compared to a case where, for example, a voltage higher than a voltage belonging to the “extra low voltage” is applied. For example, the straddled vehicle-battery pack 1 of this embodiment includes five lithium ion batteries 11 connected in series. As a result, variations in charging ability characteristics between the respective lithium ion batteries 11 included in the straddled vehicle-battery pack 1 of this embodiment can be reduced as compared to a case of, for example, using a greater number of batteries for adaptation to high voltages higher than the “extra low voltage”. Accordingly, the straddled vehicle-battery pack 1 of this embodiment can more easily keep a balance between charging amounts of the respective lithium ion batteries 11, without a control device such as a battery management system (BMS).

[0065] Each of the lithium ion batteries 11 included in the straddled vehicle- battery pack 1 of this embodiment has a maximum continuous charge rate of 10 C or more. Thus, in the straddled vehicle-battery pack 1, a maximum continuous charge rate of 10 C or more can be obtained without any parallel connection of the plural lithium ion batteries 11. For example, the straddled vehicle-battery pack 1 having a maximum continuous charge rate of 10 C or more is able to charge 50% or more of the charge capacity of the straddled vehicle-battery pack 1 within three minutes. This makes it possible that, for example, an electric motor vehicle equipped with the straddled vehicle-battery pack 1 of this embodiment is charged in a time length near a time length required for replenishment of a liquid fuel at a conventional or existing gas station. A charge station is therefore occupied for a short time. In the above, the amount of electricity charged is assumed to be, for example, 50% of the charge capacity of the straddled vehicle-battery pack 1, because it is often the case that the straddled vehicle 100, which does not have an auxiliary power supply such as an engine generator, is normally charged with a sufficient margin relative to the 0% charging amount. For instance, even when the charging amount of the straddled vehicle-battery pack 1 is more than 50%, the straddled vehicle 100 is charged frequent times (such as when the rider is at home). If it is possible that 50% or more of the straddled vehicle-battery pack 1 is charged within three minutes for example, the straddled vehicle-battery pack 1 is charged more frequently. To be specific, in one conceivable usage, if there is a charge station in a travel route, the straddled vehicle 100 makes a stopover at the charge station for a few minutes to be charged, even though the charging amount of the straddled vehicle-battery pack 1 is 70% or more. In a case of a charge station having two or more charging apparatuses for example, it is possible to distinguish a charging apparatus (fast lane) dedicated for a vehicle that will complete charging in a few minutes from a charging apparatus for the other vehicles. In such a case, a particular vehicle that will complete charging in a few minutes does not have a long waiting time and needs to stay only for a short time before its charging is completed.

[0066] The straddled vehicle-battery pack 1 of this embodiment includes the lithium ion batteries 11 that are not connected in parallel but connected in series. Therefore, the maximum continuous charge rate and the maximum charging electric current of the straddled vehicle-battery pack 1 cannot exceed the maximum continuous charge rate and the maximum charging electric current of the lithium ion batteries 11. In other words, the maximum continuous charge rate and the maximum charging electric current of the straddled vehicle- battery pack 1 are restricted mainly by the maximum continuous charge rate and the maximum charging electric current of the lithium ion batteries 11. Examples of a lithium ion battery 11 having a maximum continuous charge rate of 10 C or more include: a lithium ion battery having a charge capacity of 40 Ah or less and a maximum charging electric current of 400 A; a lithium ion battery having a charge capacity of 20 Ah or less and a maximum charging electric current of 200 A; a lithium ion battery having a charge capacity of 10 Ah or less and a maximum charging electric current of 100 A; or a lithium ion battery having a charge capacity of 5 Ah or less and a maximum charging electric current of 50 A.

[0067] Selecting a lithium ion battery having a charge capacity of 5 Ah or less makes it possible to provide a maximum continuous charge rate of 10 C or more, even when a charging electric current that can be supplied from a charging apparatus is as small as 50 A.

[0068] A maximum distance over which the straddled vehicle 100 (see FIG. 3) can travel with the charged electricity depends on a total charging amount of the straddled vehicle-battery pack 1. The total charging amount of the straddled vehicle-battery pack 1 is in proportion to the number of built-in lithium ion batteries 11. Since the lithium ion batteries 11 are not connected in parallel but connected in series, it is possible that the number of lithium ion batteries 11 is set independently of the maximum charging electric current and the maximum continuous charge rate. The number of lithium ion batteries 11 included in the straddled vehicle-battery pack 1 is equal to the number of series connections of the lithium ion batteries 11. In designing the straddled vehicle 100, the maximum distance over which the straddled vehicle 100 can travel can be set by using the number of lithium ion batteries 11 included in the straddled vehicle-battery pack 1. The charging voltage of the straddled vehicle-battery pack 1 is in proportion to the number of lithium ion batteries 11. That is, the product of a charging voltage of one lithium ion battery 11 and the number of lithium ion batteries 11 is substantially equal to the charging voltage of the straddled vehicle-battery pack 1. The maximum charging voltage of the straddled vehicle-battery pack 1 is 20 V or more and 60 V or less. Thus, the number of lithium ion batteries 11 is set such that the product mentioned above can be 60 V or less.

[0069] For example, in a case where each lithium ion battery 11 has a maximum continuous charge rate of 20 C or more, the straddled vehicle-battery pack 1 can achieve a maximum continuous charge rate of 20 C or more. In this case, the straddled vehicle-battery pack 1 can be charged in a shorter time. For example, the straddled vehicle-battery pack 1 having a maximum continuous charge rate of 20 C or more allows 50% or more of the charge capacity of the straddled vehicle-battery pack 1 to be charged within 1.5 minutes. Examples of a lithium ion battery 11 having a maximum continuous charge rate of 20 C or more include: a lithium ion battery having a charge capacity of 20 Ah or less and a maximum charging electric current of 400 A; a lithium ion battery having a charge capacity of 10 Ah or less and a maximum charging electric current of 200 A; a lithium ion battery having a charge capacity of 5 Ah or less and a maximum charging electric current of 100 A; or a lithium ion battery having a charge capacity of 2.5 Ah and a maximum charging electric current of 50 A.

[0070] For example, in a case where each lithium ion battery 11 has a maximum continuous charge rate of 40 C or more, the straddled vehicle-battery pack 1 can achieve a maximum continuous charge rate of 40 C or more. In this case, the straddled vehicle-battery pack 1 can be charged in a shorter time. For example, the straddled vehicle-battery pack 1 having a maximum continuous charge rate of 40 C or more allows 50% or more of the charge capacity of the straddled vehicle-battery pack 1 to be charged within less than one minute. Examples of a lithium ion battery 11 having a maximum continuous charge rate of 40 C or more include: a lithium ion battery having a charge capacity of 10 Ah or less and a maximum charging electric current of 400 A; a lithium ion battery having a charge capacity of 5 Ah or less and a maximum charging electric current of 200 A; or a lithium ion battery having a charge capacity of 2.5 Ah and a maximum charging electric current of 100 A.

[0071] By elimination of parallel connection of the lithium ion batteries 11, the straddled vehicle-battery pack 1 of this embodiment can keep a balance between charging amounts of the respective lithium ion batteries 11, while omitting a control device that performs a centralized control on the lithium ion batteries 11. Moreover, the insulation structure can be simplified. Accordingly, the straddled vehicle-battery pack 1 having a simple configuration and a small size can be achieved. It is possible to charge the straddled vehicle-battery pack within a short amount of time, because the straddled vehicle-battery pack 1 can achieve a maximum continuous charge rate of 10 C or more for example without any parallel connection of the plural lithium ion batteries 11. In this manner, a straddled vehicle-battery pack having a simple configuration and being small in size, and capable of charging within a short amount of time, can be achieved.

[0072] FIG. 8 is a diagram more detailing the straddled vehicle 100 shown in the part (a-1) of FIG. 1. The straddled vehicle 100 shown in FIG. 3 has the straddled vehicle- battery pack 1. The straddled vehicle 100 includes the vehicle body 102 and wheels 103a, 103b. The vehicle body 102 is provided with a motor control device 104 and the motor 105. The vehicle body 102 includes a saddle 107 and a bar handle 108 for steering. The saddle 107 is configured to have a rider sit straddling thereon. The bar handle 108 for steering is disposed so as to extend in a left-right direction of the straddled vehicle 100. The straddled vehicle 100 is, as a lean vehicle, configured to make a turn in such a manner that at a time of turning, a rider who grips the bar handle 108 shifts his / her weight so as to make the straddled vehicle 100 lean toward the inside of a curve. The straddled vehicle 100 does not include an engine as an internal combustion engine. The straddled vehicle 100 is configured without inclusion of a control device. The control device as recited herein is configured to acquire at least one parameter from among an electric current, a voltage, or a temperature detected from each of the plural lithium ion batteries 11 included in the straddled vehicle- battery pack 1. The control device is further configured to, based on the at least one parameter acquired, change the voltage and / or the electric current of at least one lithium ion battery 11. Such a control device is not disposed in the straddled vehicle-battery pack 1, either. The rear wheel 103b is a driving wheel. The motor 105 drives the wheel 103b with electricity supplied from the straddled vehicle-battery pack 1. As the wheel 103b is driven, the straddled vehicle 100 travels. Electricity in the straddled vehicle-battery pack 1 is supplied to the motor 105 via the motor control device 104. The motor control device 104 controls a supply of electricity. The straddled vehicle-battery pack 1 is connected to the motor control device 104 via the electrical connector 13. The motor control device 104 controls a supply of electricity from the straddled vehicle-battery pack 1 to the motor 105 via the mating connector, and a supply of electricity from the motor 105 to the straddled vehicle-battery pack 1 via the mating connector. That is, the straddled vehicle-battery pack 1 is connected to the vehicle body 102 of the straddled vehicle 100 via the electrical connector 13. An electric current is transmitted from the straddled vehicle-battery pack 1 to the motor control device 104 via the electrical connector 13. When, for example, braking is applied to the straddled vehicle 100 by regenerative braking of the motor 105, electricity generated in the motor 105 is supplied to the straddled vehicle-battery pack 1 via the motor control device 104. At this time, the straddled vehicle-battery pack 1 is charged.

[0073] The straddled vehicle 100 shown in FIG. 3 has a function of being charged with electricity supplied from the outside of the straddled vehicle 100. More specifically, the straddled vehicle-battery pack 1 has a function of being charged with electricity supplied from the outside of the straddled vehicle 100. For example, the mating connector disposed in the motor control device 104 is disconnected from the electrical connector 13, and a connector of a charging apparatus provided outside the straddled vehicle 100 is connected to the electrical connector 13. The connector of the charging apparatus provided outside is, for example, a connector disposed in a charging apparatus at a charge station. As the connector of the charging apparatus, for example, a connector of a charging apparatus that is installed in an ordinary home and that uses a commercial power supply may be employed.

[0074] The straddled vehicle-battery pack 1 having a maximum continuous charge rate of 10 C or more makes it possible that, for example, 50% or more of the charge capacity of the straddled vehicle-battery pack 1 is charged within three minutes. Accordingly, the straddled vehicle 100 does not need to occupy a charge station for a long time for charging.

[0075] For example, in a case where each lithium ion battery has a maximum continuous charge rate of 40 C or more, the straddled vehicle-battery pack 1 can achieve a maximum continuous charge rate of 40 C or more. In this case, the straddled vehicle-battery pack 1 can be charged in a shorter time. A charge station is occupied just for a short time, therefore.

[0076] A case where a lithium ion battery has a maximum continuous charge rate of, for example, less than 10 C will now be described as a comparative example of this embodiment.

[0077] To be able to charge the same amount of energy (electric charges) in the same charge time as in the embodiment in a straddled vehicle-battery pack including lithium ion batteries having a maximum continuous charge rate of less than 10 C; a first method may be conceivable in which the number of lithium ion batteries connected in series is increased. This is because the amount of energy (electric charges) is in proportion to the product of an electric current and a voltage of the pack. Even if the charging amount of each individual lithium ion battery is smaller than the charging amount in a full charge state, energy (electric charges) can be compensated for by increasing the number of lithium ion batteries connected in series. In this regard, however, increasing the number of lithium ion batteries connected in series so as to increase energy involves an increase in a charging voltage. As a result, a maximum charging voltage may be beyond a range of 12 V or more and 60 V or less. Moreover, increasing the number of lithium ion batteries connected in series so as to increase energy involves an increase in output voltage of the straddled vehicle battery pack. This requires a motor control device and a motor to have an increased maximum voltage. Furthermore, increasing the number of lithium ion batteries makes the straddled vehicle-battery pack larger in size.

[0078] To be able to charge the same amount of energy (electric charges) in the same charge time as in the embodiment in a straddled vehicle-battery pack including lithium ion batteries having a maximum continuous charge rate of less than 10 C; a second method may be conceivable in which the number of lithium ion batteries connected in parallel is set to more than one. Parallel connection has less voltage problems as compared to a case of a series voltage. Thus, increasing the charge rate in parallel connection is simple in principle. In a case of parallel connection, however, the straddled vehicle-battery pack becomes larger in size. First, in a case of increasing the number of lithium ion batteries connected in parallel, the number of lithium ion batteries is twice, three times, ... as compared to a case of no parallel connection. Thus, the volume of the lithium ion batteries themselves is increased. A lifetime of a lithium ion battery is easily influenced by the temperature. It therefore is necessary that as the number of lithium ion batteries increases, intervals between the respective lithium batteries are made larger so as to increase the amount of heat dissipation. The volume of the entire plural lithium ion batteries including the intervals increases. Second, coexistence of series connection and parallel connection makes wiring complicated. A space for accommodating complicated wiring is therefore required. Finally, in a case of connecting lithium ion batteries in parallel, a charging amount varies depending on variations in internal resistance between the respective lithium ion batteries. To suppress variations in charging amount, a control device for monitoring and controlling states of the lithium ion batteries connected in parallel is necessary.

[0079] The lithium ion batteries 911 shown in the part (b-2) of FIG. 1 has a maximum continuous charge rate of less than 10 C. The lithium ion batteries 911 are connected in parallel. The configuration includes two parallels and five series. In the entire straddled vehicle-battery pack 91 of the comparative example, a maximum continuous charge rate equivalent to that of the embodiment shown in the part (b-1) of FIG. 1 is achieved. Wiring 914, which connects the lithium ion batteries 911, has a complicated shape because the connection includes both parallel connection and series connection. In addition, control circuits 916, 917 are provided in order to suppress variations in charging amount between the respective lithium ion batteries 911. The control circuits 916, 917 include individual control sections 917 and a central control section 916. Each individual control section 917 has a circuit that detects an electric current of each lithium ion battery 911, and that limits the electric current. Each individual control section 917 supplies a detection result, as electric current data, to a control device. The central control section 916 calculates a charging amount of each lithium ion battery 911, from the electric current data of each lithium ion battery 911. The central control section 916 causes each individual control section 917 to limit the electric current of the corresponding lithium ion battery 911, in accordance with a calculation result. In this manner, the central control section 916 performs a control so as to keep a part of the plural lithium ion batteries 911 from overcharging.

[0080] The straddled vehicle-battery pack 91 shown in the part (b-2) of FIG. 1 is larger in size than the straddled vehicle-battery pack 1 according to the embodiment shown in the part (b-1) of FIG. 1, for example. Thus, the straddled vehicle 910 shown in the part (a-2) of FIG. 1, which is equipped with the straddled vehicle-battery pack 91, is larger than the straddled vehicle 100 according to the embodiment shown in the part (a-1) of FIG. 1.

[0081] The straddled vehicle-battery pack 1 of this embodiment shown in the part (b-1) of FIG. 1 is smaller than the straddled vehicle-battery pack 1 according to the comparative example shown in the part (b-2) of FIG. 1, for example. Thus, the straddled vehicle 100 shown in the part (a-1) of FIG. 1, which is equipped with the straddled vehicle-battery pack 1 of this embodiment, is smaller than the straddled vehicle 910 according to the comparative example shown in the part (a-2) of FIG. 1.

[0082] [Second Embodiment] FIG. 4 is a diagram schematically showing a straddled vehicle-battery pack according to a second embodiment.

[0083] A straddled vehicle-battery pack 21 according to this embodiment is different from the straddled vehicle-battery pack 1 according to the first embodiment, in that it further includes a charging-dedicated connector 15 and an electric current breaker 18. The other configurations will be given the same reference signs as given to the straddled vehicle-battery pack 1 shown in the part (1-b) of FIG. 1, and some of descriptions of the other configurations will be omitted.

[0084] Connected to the charging-dedicated connector 15 of the straddled vehicle-battery pack 21 shown in FIG. 4 is a connector of a charging apparatus disposed outside a straddled vehicle 100. The charging-dedicated connector 15 is connected in parallel with the electrical connector 13 relative to a group of lithium ion batteries 11. The charging-dedicated connector 15 is used only when the straddled vehicle-battery pack 21 is charged with electricity supplied from the outside of the straddled vehicle 100. The straddled vehicle-battery pack 21 includes the electrical connector 13 and the charging-dedicated connector 15. This allows the straddled vehicle- battery pack 21 to be charged while the vehicle body 102 of the straddled vehicle 100 is kept connected to the electrical connector 13. Accordingly, a charge operation can be easy, and moreover the degree of freedom in an installation position of the straddled vehicle-battery pack 21 can be increased.

[0085] Each lithium ion battery 11 has a negative electrode containing at least any one selected from the group consisting of a spinel structure lithium titanate, a niobium-titanium-containing composite oxide, or graphite. Each lithium ion battery 11, therefore, has wide allowable ranges of a charging voltage and a discharging voltage. The lithium ion batteries 11 are connected in series without any parallel connection that includes electrical connection between negative electrodes. Accordingly, it is easy to keep a balance between charging amounts of the respective lithium ion batteries 11, without providing a control device for performing a centralized control on the lithium ion batteries 11, such as a battery management system (BMS).

[0086] The electric current breaker 18 of the straddled vehicle-battery pack 21 allows conduction of an electric current through the lithium ion batteries 11, or blocks the electric current. The electric current breaker 18 of the straddled vehicle-battery pack 21 is configured to be brought into an on-state upon connection of a mating connector to the electrical connector 13 or to the charging-dedicated connector 15, for example. The electric current breaker 18 is configured to be brought into an on-state by an electric current conducted through a mating connector, for example. As means for creating the on-state, a device that detects physical connection or detects a signal received from a mating device upon connection may be provided, for example.

[0087] The configuration of this embodiment can suppress unintentional flow- out of the electric current of the lithium ion batteries 11 to the outside through the electrical connector 13 or the charging-dedicated connector 15. It therefore is possible to suppress the following situation: when the straddled vehicle battery pack 21 is detached from the vehicle body 102 (see FIG. 3) for example, the electrical connector 13 or the charging-dedicated connector 15 is unintentionally in contact with a conductor of some kind, and as a result, a large electric current causes the conductor to weld to the connector. Accordingly, a situation where, for example, an external conductor is welded to the electrical connector 13 or the charging-dedicated connector 15 can be suppressed with a simple configuration, without providing a control device such as a battery management system (BMS).

[0088] The present teaching is not limited to the examples given above, and for instance, the following configurations (7) to (11) may be adoptable. The above- described embodiments may be mentioned as embodiments of the (7) to (11) below.

[0089] (7) In the straddled vehicle-battery pack according to any one of (1) to (4), the casing has a fluid-tight structure.

[0090] With the foregoing configuration, even when the straddled vehicle battery pack may possibly be exposed to liquid such as water or oil, the casing suppresses intrusion of the liquid. Accordingly, contact of the liquid with the lithium ion batteries is suppressed.

[0091] (8) In the straddled vehicle-battery pack according to any one of (1) to 4), each of the plural lithium ion batteries has a maximum continuous charge rate of 40 C or more.

[0092] With the foregoing configuration, the straddled vehicle-battery pack can achieve a maximum charge rate of 40 C or more, and therefore the straddled vehicle-battery pack can be charged in a shorter time.

[0093] (9) In the straddled vehicle-battery pack according to any one of (1) to (4), each of the plural lithium ion batteries has a capacity of 5 Ah or more.

[0094] With the foregoing configuration, the straddled vehicle-battery pack can be charged to a degree that allows the straddled vehicle to travel for normal use, even though the charging is made with a voltage of 60 V or less.

[0095] (10) In the straddled vehicle-battery pack according to any one of (1) to 4), each of the plural lithium ion batteries has a capacity of 20 Ah or less.

[0096] With the foregoing configuration, the straddled vehicle-battery pack can be charged to a degree that allows the straddled vehicle to travel for long- distance travel, even though the charging is made with a voltage of 60 V or less. Reference Signs List

[0097] 1,21 straddled vehicle-battery pack 11 lithium ion battery 12 casing 13 electrical connector 18 electric current breaker 100 straddled vehicle 102 vehicle body 104 motor control device 105 motor 107 saddle 108 bar handle

Claims

CLAIMS

1. Astraddled vehicle-battery pack for use in a straddled vehicle, the straddled vehicle-battery pack comprising: plural lithium ion batteries; a casing that accommodates the plural lithium ion batteries; and an electrical connector connected to a mating connector disposed in a vehicle body of the straddled vehicle, the electrical connector being configured to transmit electric current received from and outputted to the vehicle body, the straddled vehicle-battery pack having a charge capacity of 2.5 Ah or more, a maximum charging voltage of 12 V or more and 60 V or less, and a series" connection structure in which the plural lithium ion batteries each having a maximum continuous charge rate of 10 C or more are connected in series without any parallel connection, to be able to receive and output electricity that is to be converted into motive power for increasing a driving force of the straddled vehicle, the maximum charging voltage being a voltage corresponding to a voltage across the series connection.

2. The straddled vehicle-battery pack according to claim 1, wherein each of the plural lithium ion batteries has an independent negative electrode, the independent negative electrode containing at least any one selected from the group consisting of a spinel structure lithium titanate, a niobium- titanium-containing composite oxide, and graphite, the independent negative electrode being connected to a positive electrode without being electrically connected to another independent negative electrode, to provide a series: connection structure in which the plural lithium ion batteries are connected in series without any parallel connection.

3. The straddled vehicle-battery pack according to claim 1 or 2, further comprising an electric current breaker that breaks an electric current flowing through the plural lithium ion batteries, the electric current breaker being connected in series with the plural lithium ion batteries.

4. The straddled vehicle-battery pack according to any one of claims 1 to 3, wherein the straddled vehicle-battery pack is configured without inclusion of any control device configured to acquire at least one parameter from among an electric current, a voltage, or a temperature detected from each of the plural lithium ion batteries, and based on the at least one parameter acquired, to change a voltage and / or an electric current of at least one lithium ion battery of the plural lithium ion batteries.

5. A straddled vehicle comprising: the straddled vehicle-battery pack according to any one of claims 1 to 4; a mating connector configured to be connected to the electrical connector of the straddled vehicle-battery pack; a driving wheel; a motor control device configured to control a supply of electricity from the straddled vehicle-battery pack to a motor via the mating connector and a supply of electricity from the motor to the straddled vehicle-battery pack via the mating connector; and the motor configured to drive the driving wheel with electricity supplied from the motor control device as well as to generate electricity by the driving wheel being driven, wherein the straddled vehicle is configured without inclusion of any control device that is configured to acquire at least one parameter from among an electric current, a voltage, or a temperature detected from each of the plural lithium ion batteries, and based on the at least one parameter acquired, to change a voltage and / or an electric current of at least one lithium ion battery of the plural lithium ion batteries.

6. The straddled vehicle according to claim 5, further comprising: a handle bar for steering, disposed so as to extend in the left-right direction of the straddled vehicle; and a saddle configured to have a rider sit straddling thereon, the straddled vehicle being configured, as a lean vehicle, to make a turn in such a manner that at a time of turning, a rider who grips the handle bar shifts their weight so as to make the straddled vehicle lean toward the inside of a curve.