WO2021214903A1

WO2021214903A1 - Electric vehicle battery pack and pure electric vehicle

Info

Publication number: WO2021214903A1
Application number: PCT/JP2020/017298
Authority: WO
Inventors: 日野　陽至
Original assignee: ヤマハ発動機株式会社
Priority date: 2020-04-22
Filing date: 2020-04-22
Publication date: 2021-10-28
Also published as: WO2021215425A1

Abstract

The purpose of the present invention is to provide an electric vehicle battery pack (1) which has achieved a reduction in size using a simple configuration and which is capable of being charged in a short time. The electric vehicle battery pack (1) comprises: a plurality of lithium-ion batteries (11); a case (12) which houses the plurality of lithium-ion batteries (11); and an electrical connection connector (13) which connects to a mating connector provided on the vehicle body (102) of a pure electric vehicle (100) and transfers current that is input to and output from the vehicle body (102). The plurality of lithium-ion batteries (11) each have a continuous maximum charge rate of 10C or more and are connected in series without being connected in parallel with each other, and the maximum charge voltage of the electric vehicle battery pack (1), which corresponds to the voltage across both ends of the series connection, is 60 V or less.

Description

Battery pack for electric vehicles and pure electric vehicles

The present invention relates to a battery pack for an electric vehicle and a pure electric vehicle.

For example, Patent Document 1 discloses a battery pack for a saddle-mounted vehicle. The saddle-mounted vehicle of Patent Document 1 is a vehicle without an engine, that is, a pure electric vehicle. Patent Document 1 describes an electric motorcycle as an example of a saddle-mounted vehicle. The battery pack of Patent Document 1 is provided in a saddle-mounted vehicle which is a pure electric vehicle.
The battery pack of Patent Document 1 includes a plurality of cases for accommodating a battery unit. A heat dissipation space is formed between some of the plurality of cases. As a result, in the technique of Patent Document 1, heat dissipation is increased while increasing the energy capacity of the battery pack.

Japanese Unexamined Patent Publication No. 2013-232280

It is desired that the battery pack for an electric vehicle used for a pure electric vehicle be miniaturized with a simple configuration in order to improve the mountability on the vehicle. Further, it is desired that the battery pack for an electric vehicle used for a pure electric vehicle can be charged in a short time, for example.

An object of the present invention is to provide a battery pack for an electric vehicle that can be miniaturized with a simple configuration and can be charged in a short time.

The present inventors examined the characteristics of a battery pack for an electric vehicle suitable for a pure electric vehicle. As a result, the present inventors have found the following.

In a battery pack, a plurality of batteries are usually used in combination in order to obtain a large energy capacity, that is, a charging capacity.
For example, the battery pack of Patent Document 1 has a plurality of batteries. For example, in Patent Document 1, for example, 168 batteries are connected in parallel and in series in order to increase the energy capacity. More specifically, 12 batteries connected in parallel form one set, and 14 sets are connected in series. Further, the battery pack of Patent Document 1 has a control unit. The control unit is a battery management controller (BMC) having a CPU and a memory. The control unit is connected to each battery of the battery pack by an electric wire. The control unit monitors the status of each battery. The control unit centrally controls each battery.
More specifically, a control unit connected to each battery and having a CPU and a memory monitors the state of each battery by detecting the temperature, current, voltage, frequency of use, etc. in each battery and controls each battery. do.

In the battery pack of

Patent Document

1, 12 batteries forming one set are connected in parallel. Each of the batteries connected in parallel has variations in characteristics such as internal resistance due to the state of the electrodes and the state of the electrolyte. When charging, batteries equal to each other are applied to the batteries connected in parallel. However, a current flows through the batteries connected in parallel according to the variation in characteristics. That is, strictly speaking, the charge amount of the batteries connected in parallel differs depending on the variation in the characteristics. The control unit controls the charge amount of the batteries having different charge amounts by detecting the state of each battery.

The present inventor has examined various configurations of battery packs for electric vehicles suitable for pure electric vehicles. The present inventor has studied setting the charging voltage of the battery pack for an electric vehicle to 60 V or less, and intentionally connecting a plurality of lithium ion batteries in series without connecting them in parallel with each other. Further, the present inventor has examined a lithium ion battery having a continuous maximum charging rate of 10 C or more as a battery of a battery pack for an electric vehicle. The present inventor has found that, with this configuration, the battery pack for an electric vehicle can be miniaturized with a simple configuration and can be charged in a short time.

When a plurality of lithium-ion batteries are connected in series without being connected in parallel to each other, the current flowing through each lithium-ion battery during charging is substantially equal. Therefore, it is easy to maintain the balance of the charge amount in each lithium ion battery. Therefore, for example, each lithium-ion battery does not have a control device having a CPU such as a battery management controller (BMC) or a battery management system (BMS) that centrally manages the current, voltage, or temperature of each lithium-ion battery. It is possible to keep the balance of the amount of charge in. That is, it is possible to maintain the balance of the charge amount in each lithium ion battery without a configuration in which the control device centrally controls each lithium ion battery. Therefore, a small battery pack for an electric vehicle can be realized with a simple configuration.

Further, while the plurality of lithium ion batteries are configured to be connected in series without being connected in parallel to each other, the maximum voltage that the battery pack for an electric vehicle can charge is 60 V or less. In this case, the maximum voltage applied to both ends of the plurality of lithium ion batteries connected in series is 60 V or less.
Therefore, the battery pack for electric vehicles operates within the range belonging to the "extra low voltage" (ELV or safety extra low voltage: SELV) in the standard IEC60950 of the International Electrotechnical Commission (IEC). do. Since the voltage of the battery pack for electric vehicles is low, the insulation structure can be made simpler than that for high voltage.

Further, as described above, the voltage applied to both ends of a plurality of lithium ion batteries connected in series is a low voltage belonging to the "extra low voltage". Therefore, for example, a smaller number of lithium-ion batteries can be connected in series than in the case of belonging to a voltage range higher than the "extra-low voltage" voltage. Therefore, for example, it is possible to reduce variations in the charging capacity characteristics of each lithium-ion battery included in the battery pack for an electric vehicle, as compared with the case where many lithium-ion batteries are used to cope with a high voltage. .. From this, it is possible to maintain the balance of the charge amount in each lithium ion battery without providing a control device such as a battery management system (BMS). Therefore, a small battery pack for an electric vehicle can be realized with a simple configuration.

Since each of the plurality of lithium-ion batteries connected in series has a continuous maximum charging rate of 10C or more, the continuous maximum charging rate of 10C or more as a battery pack for an electric vehicle without connecting a plurality of lithium-ion batteries in parallel. Can be realized. When the battery pack for an electric vehicle has a continuous maximum charging rate of 10 C or more, for example, 50% or more of the charging capacity of the battery pack for an electric vehicle can be charged in a short time of 3 minutes or less. This makes it possible, for example, to charge an electric vehicle equipped with a battery pack for an electric vehicle in a time close to the time required for replenishing liquid fuel in a conventional or current gas station. Therefore, it is not necessary to occupy the charging station for a long time.

In this way, by eliminating the parallel connection, it is possible to maintain the balance of the charge amount in each lithium ion battery while omitting the control device such as the battery management controller (BMC). In addition, the insulating structure can be simplified. It is possible to realize a small battery pack for an electric vehicle with a simple configuration. Further, since a maximum charging rate of 10 C or more can be realized as a battery pack for an electric vehicle without connecting a plurality of lithium ion batteries in parallel, the battery pack for an electric vehicle can be charged in a short time.
In this way, it is possible to realize a battery pack for an electric vehicle that has a simple configuration, is compact, and can be charged in a short time.

The battery pack for an electric vehicle according to each viewpoint of the present invention completed based on the above findings has the following configurations.

(1) A battery pack for an electric vehicle used for a pure electric vehicle.
The battery pack for an electric vehicle is
With multiple lithium-ion batteries
A case accommodating the plurality of lithium ion batteries and
An electrical connection connector that is connected to a mating connector provided on the vehicle body of the pure electric vehicle and transmits a current input / output to the vehicle body.
With
Each of the plurality of lithium-ion batteries has a continuous maximum charging rate of 10 C or more and is connected in series without being connected in parallel to each other, and the maximum charge of the battery pack for an electric vehicle corresponding to the voltage across the series connection. The voltage is 60 V or less.

The battery pack for an electric vehicle in the above configuration includes a plurality of lithium ion batteries. A plurality of lithium-ion batteries are connected in series without being connected in parallel with each other. Therefore, the currents flowing through each lithium-ion battery during charging are substantially equal. Therefore, it is easy to maintain the balance of the charge amount in each lithium ion battery. Therefore, for example, it is possible to maintain the balance of the charge amount in each lithium-ion battery without providing a control device such as a battery management system (BMS) that centrally manages the current, voltage, or temperature of each lithium-ion battery. Is. Therefore, a small battery pack for an electric vehicle can be realized with a simple configuration.

Further, as described above, the voltage applied to both ends of the plurality of lithium ion batteries connected in series is a low voltage belonging to the “extra low voltage”. Therefore, for example, a smaller number of lithium-ion batteries can be connected in series than in the case of belonging to a voltage range higher than the "extra-low voltage" voltage. Therefore, for example, it is possible to reduce variations in the charging capacity characteristics of each lithium-ion battery included in the battery pack for an electric vehicle, as compared with the case where many lithium-ion batteries are used to cope with a high voltage. .. From this, it is possible to maintain the balance of the charge amount in each lithium ion battery without providing a control device such as a battery management system (BMS). Therefore, a small battery pack for an electric vehicle can be realized with a simple configuration.
Since each of the plurality of lithium-ion batteries connected in series has a continuous maximum charging rate of 10C or more, the continuous maximum charging rate of 10C or more as a battery pack for an electric vehicle without connecting a plurality of lithium-ion batteries in parallel. Can be realized. When the battery pack for an electric vehicle has a continuous maximum charging rate of 10 C or more, for example, 50% or more of the charging capacity of the battery pack for an electric vehicle can be charged within 3 minutes.

In this way, by eliminating the parallel connection, it is possible to maintain the balance of the charge amount in each lithium ion battery while omitting the control device such as the battery management controller (BMC). In addition, the insulating structure can be simplified. A battery pack for a small electric vehicle can be realized with a simple configuration. Further, since a continuous maximum charging rate of 10 C or more can be realized as a battery pack for an electric vehicle without connecting a plurality of lithium ion batteries in parallel, the battery pack for an electric vehicle can be charged in a short time.
In this way, it is possible to realize a battery pack for an electric vehicle that has a simple configuration, is compact, and can be charged in a short time.

According to one viewpoint of the present invention, the battery pack for an electric vehicle can adopt the following configuration.

(2) The battery pack for electric vehicles of (1).
Each of the plurality of lithium ion batteries has a negative electrode containing at least one selected from the group consisting of spinel-type lithium titanate, niobium titanium-containing composite oxide, and graphite.

According to the above configuration, it is possible to suppress deformation of the crystal structure that receives lithium ions before and after the inflow and outflow of lithium ions from the negative electrode due to charging or discharging. Therefore, the allowable range of charge voltage and discharge voltage is wider than that of a lithium ion battery in which the negative electrode does not have any of spinel-type lithium titanate, niobium-titanium-containing composite oxide, and graphite. Therefore, it is easy to keep the balance of the charge amount in each lithium ion battery without providing a control device such as a battery management system (BMS). Therefore, a small battery pack for an electric vehicle can be realized with a simpler configuration.

According to one aspect of the present invention, the battery pack for an electric vehicle can adopt the following configuration.
(3) The battery pack for an electric vehicle according to (1) or (2).
A relay that is connected in series with the plurality of lithium ion batteries and cuts off the current flowing through the plurality of lithium ion batteries is provided.

According to the above configuration, it is possible to suppress a situation in which the currents of a plurality of lithium ion batteries inadvertently flow from the electrical connection connector to the outside. For this reason, for example, when the battery pack for an electric vehicle is removed from the vehicle body or during the work of being attached to the vehicle body, the electric connector carelessly contacts some conductor outside the battery pack for the electric vehicle and causes a short circuit. It is possible to suppress the situation where the conductor is welded to the electrical connector due to a large current. Therefore, without providing a control device such as a battery management system (BMS), it is possible to suppress a situation in which, for example, an external conductor is welded to an electrical connection connector with a simple configuration.

According to one aspect of the present invention, the battery pack for an electric vehicle can adopt the following configuration.
(4) A battery pack for an electric vehicle according to any one of (1) to (3).
The battery pack for an electric vehicle acquires at least one parameter of the current, voltage, or temperature detected from each of the plurality of lithium ion batteries, and based on the acquired at least one parameter, the said battery pack. It does not include a control device configured to change the voltage and / or current of at least one of the plurality of lithium ion batteries.

In the above configuration, each of the plurality of lithium-ion batteries has a continuous maximum charging rate of 10 C or more and is connected in series without being connected in parallel to each other, and is a battery pack for an electric vehicle corresponding to the voltage across the series connection. The maximum charging voltage is 60 V or less. Since each of the plurality of lithium-ion batteries is not connected in parallel, the above configuration can maintain the balance of the charge amount in each lithium-ion battery while omitting the above-mentioned control device. Therefore, it is possible to realize a battery pack for an electric vehicle that has a simple configuration, is compact, and can be charged in a short time.

According to one aspect of the present invention, the battery pack for an electric vehicle can adopt the following configuration.
(5) It is a pure electric vehicle
The pure electric vehicle is
A battery pack for an electric vehicle according to any one of (1) to (4) and
A mating connector configured to be connected to the electrical connector of the battery pack for an electric vehicle,
With the drive wheels
Motor control configured to control power supply from the battery pack for an electric vehicle to a motor via the mating connector and power supply from the motor to the battery pack for an electric vehicle via the mating connector. With the device
The motor is provided with the motor configured to drive the drive wheels with electric power supplied from the motor control device, while generating electric power by driving the drive wheels.
Of the plurality of lithium ion batteries, at least one parameter of the current, voltage or temperature detected from each of the plurality of lithium ion batteries is acquired, and based on the acquired at least one parameter, among the plurality of lithium ion batteries. It does not include a control device configured to change the voltage and / or current of at least one of the lithium-ion batteries.

According to the above configuration, it is possible to realize a pure electric vehicle that has a simple configuration, is compact, and can charge the battery pack in a short time.

(6) The pure electric vehicle of (5)
The pure electric vehicle is a saddle-mounted vehicle.
The saddle-mounted vehicle is
A steering bar handle provided so as to extend in the left-right direction of the saddle-mounted vehicle, and
Equipped with a saddle configured for the driver to sit across
As a lean vehicle, the driver who grips the bar handle at the time of turning is configured to turn by shifting the weight so as to lean inward of the curve.

For a saddle-type vehicle as a lean vehicle, responsiveness and agility to the driver's operation are important, and there is a high demand for miniaturization. On the other hand, pure electric vehicles are equipped with battery packs. Therefore, for a pure electric saddle-type vehicle as a lean vehicle, it was difficult to achieve a high level of responsiveness and agility. However, according to the above configuration, it is possible to provide a pure electric saddle-type vehicle as a lean vehicle, which is excellent in responsiveness and lightness, can be miniaturized with a simple configuration, and can charge a battery pack in a short time.

A pure electric vehicle is a vehicle that runs on the electric power stored in a battery pack. The electric power referred to here includes, for example, at least the chemical energy stored in the secondary battery pack. The pure motor vehicle may also include a capacitor and may be configured to run on the physical energy stored in the capacitor in addition to the chemical energy. A pure motor vehicle is, for example, a vehicle that does not have an engine. Vehicles equipped with an engine as an internal combustion engine are not included in pure electric vehicles. For example, a plug-in hybrid vehicle that has a function of charging with electric power supplied from the outside of the vehicle and can run on an engine mounted on the vehicle is not included in a pure electric vehicle.
The pure electric vehicle is, for example, a saddle-mounted vehicle. That is, the pure electric vehicle is, for example, a pure electric saddle type vehicle. A saddle-mounted vehicle is a vehicle that rides in a riding style. The driver sits across the saddle of a saddle-mounted vehicle. The saddle-mounted vehicle is, for example, a lean vehicle. Examples of the saddle-type vehicle include a scooter type, a moped type, an off-road type, and an on-road type motorcycle. Further, the saddle-mounted vehicle is not limited to a motorcycle, and may be, for example, an ATV (All-Terrain Vehicle) or the like, or may be a motorcycle. A tricycle may have two front wheels and one rear wheel, or may have one front wheel and two rear wheels. The pure electric vehicle is not particularly limited, and may be, for example, an automobile having four or more wheels and a passenger compartment.

The battery pack for electric vehicles is a battery pack used for pure electric vehicles. A battery pack for an electric vehicle is a pack in which a plurality of lithium-ion batteries are integrally combined. The battery pack for an electric vehicle is mounted on the body of a pure electric vehicle. The battery pack for electric vehicles is removable from the vehicle body. However, the battery pack for an electric vehicle may be removable from the vehicle body without a tool other than a key such as a spanner, or may be removable from the vehicle body by using a tool such as a spanner.

Lithium-ion batteries are batteries that can be charged and discharged. A lithium ion battery is a secondary battery that charges and discharges by a chemical reaction of electrodes. Lithium-ion batteries are charged and discharged by oxidation and reduction reactions of electrodes. Lithium-ion batteries convert stored chemical energy into electrical energy. The terminal voltage of a lithium-ion battery is not proportional to the amount of power stored in the battery. For example, lithium ion capacitors are not included in lithium ion batteries.
Lithium-ion batteries contain a lithium oxide in the positive electrode. Lithium batteries that use lithium metal for the positive electrode are not included in lithium ion batteries. The lithium ion battery is a non-aqueous lithium ion battery that uses a non-aqueous electrolyte such as an organic solvent.
A lithium-ion battery is a battery that can store electric power for driving a motor of a pure electric vehicle. Lithium-ion batteries can store electric power supplied from the outside of a pure electric vehicle. Further, the lithium ion battery can store the electric power supplied from the motor when the motor of the pure electric vehicle generates electric power. That is, the regenerative current of the motor can be stored.

The maximum charging rate is the maximum maximum charging rate allowed by the power storage unit. The maximum charging rate represents the speed of charging. The unit is C. The continuous maximum charge rate is the maximum maximum charge rate allowed when charging continuously rather than instantaneously. In the case of continuous charging, that is, in the case of constant current charging measurement, the magnitude of the current that completely charges the capacity of the battery in one hour is defined as 1C. For example, when the capacity of the battery is 2Ah, 1C is 2A.

The electrical connector transmits the current input and output to the vehicle body. For example, the electrical connector transmits the current output to the motor of a pure electric vehicle. Also, for example, the electrical connector transmits the current supplied by the motor when the motor of a pure electric vehicle generates electricity.
The electrical connector may be used as a connector for transmitting a current supplied from the outside of a pure electric vehicle. However, the electrical connection connector may be provided as a connector different from the connector that transmits the current supplied from the outside of the pure electric vehicle.

Further, the electrical connector is attached to, for example, a case. The electrical connector is supported, for example, in a case. The electrical connector is fixed to the case, for example.
However, the electrical connection connector is not limited to this, and may be swingably supported by the case so that it can be easily connected to the mating connector, for example. Further, the electrical connector may be connected to, for example, a cable extending through the case and extending to the outside of the case. That is, the electrical connector may be physically connected to the case via a cable without being supported by the case. That is, the electrical connector does not have to be attached to the case, for example.

The connection includes a state in which an electrical component is inserted in the middle. Examples of such electrical components include switches, relays, resistors, connection terminals, and fuses. The connection is, for example, by wiring a lead wire. However, the wiring is not limited to one composed of one lead wire, and may be a plurality of connected lead wires.

The terminology used herein is for the purpose of defining only specific embodiments and is not intended to limit the invention.
As used herein, the term "and / or" includes any or all combinations of one or more related listed components.
As used herein, the use of the terms "including, including,""comprising," or "having," and variations thereof, is a feature, process, operation, described. It identifies the presence of elements, components and / or their equivalents, but can include one or more of steps, actions, elements, components, and / or groups thereof.
As used herein, the terms "attached", "combined" and / or their equivalents are widely used and are both direct and indirect attachments and bindings unless otherwise specified. Including.
Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.
Terms such as those defined in commonly used dictionaries should be construed to have meaning consistent with the relevant technology and in the context of the present disclosure and are expressly defined herein. Unless it is, it will not be interpreted in an ideal or overly formal sense.
It is understood that a number of techniques and processes are disclosed in the description of the present invention.
Each of these has its own interests, and each may be used in conjunction with one or more of the other disclosed techniques, or in some cases all.
Therefore, for clarity, this description refrains from unnecessarily repeating all possible combinations of individual steps.
Nevertheless, the specification and claims should be read with the understanding that all such combinations are within the scope of the present invention and claims.
This specification describes a new battery pack for an electric vehicle.
In the following description, for purposes of illustration, a number of specific details are given to provide a complete understanding of the present invention.
However, it will be apparent to those skilled in the art that the present invention can be practiced without these particular details.
The present disclosure should be considered as an example of the invention and is not intended to limit the invention to the particular embodiments set forth in the drawings or description below.

According to the present invention, it is possible to realize a battery pack for an electric vehicle that can be miniaturized with a simple configuration and can be charged in a short time.

It is a figure which shows typically the battery pack for electric vehicles which concerns on 1st Embodiment of this invention. It is a figure which shows the outline of a pure electric vehicle as an application example of the battery pack for an electric vehicle shown in FIG. It is a figure which shows typically the battery pack for electric vehicles which concerns on 2nd Embodiment of this invention.

Hereinafter, the present invention will be described based on the embodiments with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram schematically showing a battery pack for an electric vehicle according to the first embodiment of the present invention.

The battery pack 1 for an electric vehicle shown in FIG. 1 is a battery pack used for a pure electric vehicle 100 (see FIG. 2). The battery pack 1 for an electric vehicle is a battery pack that can be charged and discharged. The battery pack 1 for an electric vehicle is charged at a voltage equal to or lower than the maximum charging voltage. The maximum charging voltage of the battery pack 1 for an electric vehicle is 60 V or less. The maximum charging voltage of the battery pack 1 for an electric vehicle is, for example, 48V. However, the maximum charging voltage may be set to, for example, 14V, or may be set to, for example, 36V.

The battery pack 1 for an electric vehicle includes a lithium ion battery 11, a case 12, and an electric connector 13.

In the example shown in FIG. 1, the battery pack 1 for an electric vehicle includes five lithium ion batteries 11. The lithium ion batteries 11 are connected in series without being connected in parallel with each other.
The number of lithium-ion batteries 11 is set so that the maximum voltage across the series is equal to or greater than the maximum voltage of the battery pack 1 for an electric vehicle.
The lithium ion battery 11 is a battery that can be charged and discharged. The lithium ion battery 11 is a secondary battery that charges and discharges by a chemical reaction of electrodes. The lithium ion battery 11 contains a lithium oxide in the positive electrode. The lithium ion battery is a non-aqueous lithium ion battery that uses a non-aqueous electrolyte. The lithium ion battery contains, for example, at least one selected from the group consisting of spinel-type lithium titanate, niobium titanium-containing composite oxide, and graphite in the negative electrode. However, the negative electrode of the lithium ion battery is not particularly limited, and a negative electrode containing a substance other than the above can also be adopted.
The lithium ion battery 11 has a larger maximum charging current than a battery using another positive electrode material such as a lead battery or a nickel hydrogen battery. The lithium ion battery 11 has a continuous maximum charging rate of 10 C or more.

The case 12 houses the lithium-ion battery 11. Case 12 has, for example, a closed structure.
More specifically, the case 12 has a structure in which the lithium ion battery 11 cannot be seen from the outside. As a result, the situation in which a foreign substance is inserted from the outside of the battery pack 1 for an electric vehicle and comes into contact with the lithium ion battery 11 is suppressed.
More specifically, the case 12 has, for example, a waterproof structure. For example, when the battery pack 1 for an electric vehicle is provided in a saddle-type vehicle as a pure electric vehicle (see FIG. 2), the battery pack 1 for an electric vehicle may be exposed to a liquid such as water or oil. The case 12 suppresses the ingress of liquid. Therefore, the contact between the lithium ion battery 11 and the liquid is suppressed.

The electric connection connector 13 is connected to a mating connector (not shown) provided on the vehicle body 102 (see FIG. 2) of the pure electric vehicle 100, and transmits an input / output current to the vehicle body 102. The electric power stored in the battery pack 1 for the electric vehicle is supplied to the vehicle body of the pure electric vehicle through the electric connector 13.
Further, at the time of regeneration, the regenerative power is supplied from the vehicle body of the pure electric vehicle to the battery pack 1 for the electric vehicle through the electric connector 13.
The electrical connection connector 13 of the present embodiment can also be connected to a charging device provided outside the pure electric vehicle 100, such as a charging station. While the pure electric vehicle 100 is stopped, the mating connector provided in the external charging device is connected instead of the mating connector provided in the vehicle body 102 (see FIG. 2). As a result, the battery pack 1 for the electric vehicle is charged.

The battery pack 1 for electric vehicles is also equipped with a bus bar 14. The bus bar 14 is a conductor that connects the lithium ion battery 11 and the electrical connector 13. The bus bar 14 connects the lithium ion batteries 11 to each other. The bus bar 14 connects the lithium ion battery 11 and the electrical connector 13 in series.

The lithium ion batteries 11 included in the battery pack 1 for an electric vehicle of the present embodiment are connected in series without being connected in parallel to each other. Each lithium-ion battery 11 has a variation in internal resistance. However, the currents flowing through the lithium-ion batteries 11 connected in series are substantially equal regardless of the difference in internal resistance. Therefore, it is easy to maintain the balance of the charge amount in each lithium ion battery 11.
For example, when charging is started from a state where the charge amount of each lithium ion battery 11 is 0, the current integrated amount of each lithium ion battery 11 at an arbitrary time is substantially equal. That is, the charge amount of each lithium ion battery 11 is substantially equal. Further, even when each lithium ion battery 11 is discharged, the current flowing through each lithium ion battery 11 is substantially equal. Therefore, the charge amount of each lithium ion battery 11 at an arbitrary time is substantially equal. Therefore, the timing at which each lithium ion battery 11 is fully charged during charging is substantially the same.
Therefore, for example, it is possible to maintain the balance of the charge amount in each lithium-ion battery without providing a control device such as a battery management system (BMS) that centrally manages the current, voltage, or temperature of each lithium-ion battery. Is. Therefore, the battery pack 1 for an electric vehicle can be miniaturized with a simple configuration.
The standard working voltage of each lithium ion battery 11 is, for example, 2.3V. However, each lithium ion battery 11 can be charged with a voltage exceeding the standard working voltage. Each lithium ion battery 11 is charged with a voltage of, for example, 3 V or more.

Further, the lithium ion battery 11 is configured to be connected in series without being connected in parallel to each other, and the maximum voltage that can be charged by the battery pack 1 for an electric vehicle is 60 V or less. In this case, the maximum voltage applied to both ends of the set of lithium ion batteries 11 connected in series is 60 V or less.

The battery pack 1 for an electric vehicle operates in a range belonging to the "extra low voltage" (ELV or safety extra low voltage: SELV) in the standard IEC60950 of the International Electrotechnical Commission (IEC). The potential difference of any node inside the battery pack 1 for an electric vehicle does not exceed 60 V.
Therefore, the degree of insulation of each node used in the battery pack is sufficient within the range of "operational insulation". Since the voltage of the battery pack 1 for an electric vehicle is a low voltage, an insulating structure can be made simpler than that for a high voltage.

For example, as the lithium ion battery 11, a lithium ion battery having a charging capacity of 5 Ah or more and 40 Ah or less can be adopted. When the maximum charging voltage of such a lithium ion battery 11 is 3V, the maximum charging voltage of the battery pack 1 for an electric vehicle having five lithium ion batteries 11 connected in series is 15V.
For example, when the lithium ion battery 11 has a charge capacity of 5 Ah and a continuous maximum charge rate of 10 C, the continuous maximum charge flow of the lithium ion battery 11 is 50 A. Further, for example, when the lithium ion battery 11 has a charge capacity of 20 Ah and a continuous maximum charge rate of 10 C, the continuous maximum charge flow of the lithium ion battery 11 is 200 A. As described above, the ability to fully charge the battery is difficult to grasp only from the charging current. This is because the ability of a battery to be fully charged depends not only on the charging current but also on the charging capacity. Therefore, in the present specification, as a capacity for the battery to be fully charged, a display based on a charging rate in consideration of a difference in charging capacity is adopted.

Further, as described above, the voltage applied to both ends of the plurality of lithium ion batteries connected in series is a low voltage belonging to the “extra low voltage”. Therefore, for example, a smaller number of lithium-ion batteries 11 can be connected in series as compared with the case where a voltage higher than the "extra-low voltage" is applied. For example, the battery pack 1 for an electric vehicle of the present embodiment has five lithium ion batteries 11 connected in series.
Therefore, for example, as compared with the case where many lithium-ion batteries are used to cope with a high voltage higher than the "extra-low voltage", the battery pack 1 for an electric vehicle of the present embodiment is made of each lithium-ion battery 11. It is possible to reduce variations in the characteristics of charging capacity.
For this reason, the battery pack 1 for an electric vehicle of the present embodiment can more easily maintain the balance of the charge amount in each lithium ion battery without providing a control device such as a battery management system (BMS).

Since each lithium ion battery included in the battery pack 1 for an electric vehicle of the present embodiment has a continuous maximum charging rate of 10C or more, 10C as the battery pack 1 for an electric vehicle without connecting a plurality of lithium ion batteries in parallel. The above continuous maximum charging rate can be realized.
For example, when the battery pack 1 for an electric vehicle has a continuous maximum charging rate of 10 C or more, it is possible to charge 50% or more of the charging capacity of the battery pack 1 for an electric vehicle within 3 minutes. As a result, for example, the electric vehicle equipped with the battery pack 1 for the electric vehicle of the present embodiment can be charged in a time close to the time required for replenishing the liquid fuel in the conventional or current gas station. Therefore, the time to occupy the charging station is short.
Here, the assumption of the amount of electric power to be charged is, for example, 50% of the charging capacity of the battery pack for an electric vehicle.
This is because a pure electric vehicle that does not have an auxiliary power source such as an engine generator is usually charged with a sufficient margin for a charge amount of 0%. For example, a pure electric vehicle is charged at a high frequency, for example, when the driver is at home, even when the charge amount of the battery pack 1 for the electric vehicle is more than 50%.
For example, if 50% or more of the battery pack 1 for an electric vehicle can be charged within 3 minutes, the battery pack 1 for an electric vehicle will be charged more frequently. Specifically, when there is a charging station on the traveling path, even if the charge amount of the battery pack 1 for an electric vehicle is 70% or more, it is conceivable to stop by the charging station for several minutes to charge the battery pack 1.
Further, for example, when the charging station is equipped with a plurality of charging devices, it is possible to distinguish between a charging device dedicated to a vehicle (first lane) that completes charging within a few minutes and a charging device for a vehicle that does not. .. In this case, a specific vehicle that can be fully charged within a few minutes has a short waiting time and can be charged after a short stay.

The battery pack 1 for an electric vehicle of the present embodiment has a lithium ion battery 11 connected in series without being connected in parallel. Therefore, the continuous maximum charging rate and the maximum charging current of the battery pack 1 for the electric vehicle cannot exceed the continuous maximum charging rate and the maximum charging current of the lithium ion battery 11. In other words, the continuous maximum charging rate and the maximum charging current of the battery pack 1 for the electric vehicle are mainly restricted by the continuous maximum charging rate and the maximum charging current of the lithium ion battery 11.
As an example of the lithium ion battery 11 having a continuous maximum charging rate of 10 C or more, for example,
A lithium-ion battery with a charging capacity of 40 Ah or less and a maximum charging current of 400 A,
A lithium-ion battery with a charging capacity of 20 Ah or less and a maximum charging current of 200 A,
A lithium-ion battery having a charging capacity of 10 Ah or less and a maximum charging current of 100 A, or
Lithium-ion batteries having a charging capacity of 5 Ah or less and a maximum charging current of 50 A can be mentioned.

By selecting a lithium-ion battery having a charging capacity of 5 Ah or less, it is possible to provide a continuous charging rate of 10 C or more even if the charging current that can be supplied from the charging device is about 50 A.

On the other hand, the maximum distance that the pure electric vehicle 100 (see FIG. 2) can travel with the charged electric power depends on the total charge amount of the battery pack 1 for the electric vehicle. The total charge amount of the battery pack 1 for an electric vehicle is proportional to the number of built-in lithium ion batteries 11. Since the lithium ion batteries 11 are connected in series without being connected in parallel, the number of lithium ion batteries 11 can be set independently of the maximum charging current and the maximum continuous charging rate. The number of lithium-ion batteries 11 included in the battery pack 1 for an electric vehicle is equal to the number of series-connected lithium-ion batteries 11.
In the design of the pure electric vehicle 100, the maximum distance that the pure electric vehicle 100 can travel can be set by the number of lithium ion batteries 11 included in the battery pack 1 for the electric vehicle.
The charging voltage of the battery pack 1 for an electric vehicle is proportional to the number of lithium ion batteries 11. That is, when the continuous charge rate [C] of the battery pack 1 for an electric vehicle is maintained at the same level as the continuous charge rate of each lithium ion battery 11, the charge voltage of one lithium ion battery 11 and the number of lithium ion batteries 11 are maintained. Is substantially the charging voltage of the battery pack 1 for the electric vehicle.
The maximum charging voltage of the battery pack 1 for an electric vehicle is 60 V or less. Therefore, the number of lithium ion batteries 11 is set so that the above product is 60 V or less.

For example, when each lithium-ion battery has a continuous maximum charging rate of 20C or more, a continuous maximum charging rate of 20C or more can be realized as the battery pack 1 for an electric vehicle. In this case, the battery pack 1 for the electric vehicle can be charged in a shorter period of time.
For example, when the battery pack for an electric vehicle has a continuous maximum charging rate of 20 C or more, it is possible to charge 50% or more of the charging capacity of the battery pack 1 for an electric vehicle within 1.5 minutes.
As an example of the lithium ion battery 11 having a continuous maximum charging rate of 20 C or more, for example,
A lithium-ion battery with a charging capacity of 20 Ah or less and a maximum charging current of 400 A,
A lithium-ion battery with a charging capacity of 10 Ah or less and a maximum charging current of 200 A,
A lithium-ion battery having a charging capacity of 5 Ah or less and a maximum charging current of 100 A, or
Lithium-ion batteries having a charging capacity of 2.5 Ah or less and a maximum charging current of 50 A can be mentioned.

For example, when each lithium-ion battery has a continuous maximum charging rate of 40C or more, a continuous maximum charging rate of 40C or more can be realized as the battery pack 1 for an electric vehicle. In this case, the battery pack 1 for the electric vehicle can be charged in a shorter period of time.
For example, when the battery pack for an electric vehicle has a continuous maximum charging rate of 40 C or more, it is possible to charge 50% or more of the charging capacity of the battery pack 1 for an electric vehicle in less than one minute.
As an example of the lithium ion battery 11 having a continuous maximum charging rate of 40 C or more, for example,
A lithium-ion battery with a charging capacity of 10 Ah or less and a maximum charging current of 400 A,
A lithium-ion battery with a charging capacity of 5 Ah or less and a maximum charging current of 200 A,
A lithium-ion battery having a charging capacity of 2.5 Ah or less and a maximum charging current of 100 A, or
Lithium-ion batteries having a charging capacity of 1.25 Ah or less and a maximum charging current of 50 A can be mentioned.

As described above, according to the battery pack 1 for an electric vehicle of the present embodiment, by eliminating the parallel connection of the lithium ion batteries 11, each lithium ion battery 11 is omitted while omitting a control device such as a battery management controller (BMC). It is possible to keep the balance of the amount of charge in. In addition, the insulating structure can be simplified. Therefore, a small battery pack 1 for an electric vehicle can be realized with a simple configuration. Then, since a continuous maximum charging rate of, for example, 10 C or more can be realized as the battery pack 1 for an electric vehicle without connecting a plurality of lithium ion batteries 11 in parallel, the battery pack for an electric vehicle can be charged in a short time.
In this way, it is possible to realize a battery pack for an electric vehicle that has a simple configuration, is compact, and can be charged in a short time.

FIG. 2 is a diagram showing an outline of a pure electric vehicle as an application example of the battery pack 1 for an electric vehicle shown in FIG.
The pure electric vehicle 100 shown in FIG. 2 has a battery pack 1 for an electric vehicle. The pure electric vehicle 100 includes a vehicle body 102 and

wheels

103a and 103b. The vehicle body 102 is provided with a motor control device 104 and a motor 105. The vehicle body 102 includes a saddle 107 and a bar handle 108 for steering. The saddle 107 is configured so that the driver sits across it. The steering bar handle 108 is provided so as to extend in the left-right direction of the pure electric vehicle 100. The pure electric vehicle 100 is configured to turn as a lean vehicle by shifting the weight so as to lean inward of the curve by a driver who holds the bar handle 108 at the time of turning. The pure electric vehicle 100 does not include an engine as an internal combustion engine. The pure electric vehicle 100 does not have a control device. The control device referred to here acquires at least one parameter of the current, voltage, or temperature detected from each of the plurality of lithium ion batteries 11 in the battery pack 1 for an electric vehicle, and at least one of the acquired parameters. It is configured to change the voltage and / or current of at least one lithium ion battery 11 among the plurality of lithium ion batteries 11 based on the parameters. Such a control device is also not provided in the battery pack 1 for an electric vehicle.
The rear wheel 103b is a driving wheel. The motor 105 drives the wheels 103b by the electric power supplied from the battery pack 1 for the electric vehicle. The pure electric vehicle 100 runs by driving the wheels 103b.
The electric power of the battery pack 1 for the electric vehicle is supplied to the motor 105 via the motor control device 104. The battery pack 1 for an electric vehicle is connected to the motor control device 104 via the electric connection connector 13. That is, the battery pack 1 for the electric vehicle is connected to the vehicle body 102 of the pure electric vehicle 100 via the electric connection connector 13. The electric current is transmitted from the battery pack 1 for the electric vehicle to the motor control device 104 via the electric connector 13.
For example, when the pure electric vehicle 100 is braked by the regenerative braking of the motor 105, the power generated by the motor 105 is supplied to the electric vehicle battery pack 1 via the motor control device 104. At this time, the battery pack 1 for the electric vehicle is charged.

The pure electric vehicle 100 shown in FIG. 2 has a function of being charged by electric power supplied from the outside of the pure electric vehicle 100. More specifically, the battery pack 1 for an electric vehicle has a function of being charged by electric power supplied from the outside of the pure electric vehicle 100.
For example, the mating connector provided in the motor control device 104 is removed from the electric connection connector 13, and the connector of the charging device provided outside the pure electric vehicle 100 is connected to the electric connection connector 13. The connector of the charging device provided externally is, for example, a connector provided in the charging device of the charging station. As the connector of the charging device, for example, a connector of a charging device provided in a general household and using a commercial power source can also be adopted.

Since the battery pack for an electric vehicle has a continuous maximum charging rate of 10 C or more, for example, 50% or more of the charging capacity of the battery pack 1 for an electric vehicle can be charged within 3 minutes. Therefore, the pure electric vehicle 100 does not need to occupy the charging station for a long time for charging.

For example, when each lithium-ion battery has a continuous maximum charging rate of 40C or more, a continuous maximum charging rate of 40C or more can be realized as the battery pack 1 for an electric vehicle. In this case, the battery pack 1 for the electric vehicle can be charged in a shorter period of time. Therefore, the time to occupy the charging station is short.

[Second Embodiment]
FIG. 3 is a diagram schematically showing a battery pack for an electric vehicle according to a second embodiment of the present invention.

The electric vehicle battery pack 21 according to the present embodiment is different from the electric vehicle battery pack 1 according to the first embodiment in that it further includes a charging connector 15 and a relay 18. Other configurations are designated by the same reference numerals as those of the battery pack 1 for electric vehicles shown in FIG. 1, and some description thereof will be omitted.

The dedicated charging connector 15 of the battery pack 21 for an electric vehicle shown in FIG. 3 is connected to a connector of a charging device provided outside the pure electric vehicle 100. The charging-dedicated connector 15 is connected to the set of lithium-ion batteries 11 in parallel with the electrical connection connector 13. The charging-dedicated connector 15 is used only when the battery pack 21 for the electric vehicle is charged by the electric power supplied from the outside of the pure electric vehicle 100.
The battery pack 21 for an electric vehicle has an electric connection connector 13 and a charging-only connector 15. Therefore, the battery pack 21 for the electric vehicle can be charged while maintaining the connection state of the vehicle body 102 of the pure electric vehicle 100 with respect to the electric connection connector 13. Therefore, the charging operation can be facilitated, and the degree of freedom in the installation position of the battery pack 21 for the electric vehicle can be increased.

Each lithium ion battery 11 has a negative electrode containing at least one selected from the group consisting of spinel-type lithium titanate, niobium titanium-containing composite oxide, and graphite. Therefore, each lithium ion battery 11 has a wide allowable range of charge voltage and discharge voltage. Therefore, it is easy to keep the balance of the charge amount in each lithium ion battery without providing a control device such as a battery management system (BMS).

The relay 18 of the battery pack 21 for an electric vehicle conducts or cuts off the current flowing through the lithium ion battery 11.
The relay 18 of the battery pack 21 for an electric vehicle is configured to be turned on when, for example, a mating connector is connected to the electric connection connector 13 or the charging-only connector 15. For example, it is configured to be turned on by the current that energizes the mating connector. As a means for turning on the state, for example, a device for detecting a physical connection or a signal received from the other party at the time of connection may be provided.

According to the configuration of the present embodiment, it is possible to suppress a situation in which the current of the lithium ion battery 11 carelessly flows to the outside from the electric connection connector 13 or the charging dedicated connector 15. Therefore, for example, when the battery pack 21 for an electric vehicle is removed from the vehicle body 102 (see FIG. 2) or during the work of being attached to the vehicle body, the electric connection connector 13 or the charging-dedicated connector 15 is the battery pack for the electric vehicle. It is possible to prevent a situation in which the conductor is inadvertently contacted with some conductor outside the 21 and the conductor is welded to the electric connection connector 13 or the charging dedicated connector 15 due to a large current due to a short circuit.
Without providing a control device such as a battery management system (BMS), it is possible to suppress a situation in which, for example, an external conductor is welded to the electrical connection connector 13 or the charging-only connector 15 with a simple configuration.

The present invention is not limited to the above-mentioned example, and for example, the following configurations (7) to (11) can be adopted. Examples of the following embodiments (7) to (11) include the above-described embodiments.

(7) A battery pack for an electric vehicle according to any one of (1) to (4).
The case has a liquidtight structure.

According to the above configuration, even if the battery pack for an electric vehicle may be exposed to a liquid such as water or oil, the ingress of the liquid is suppressed depending on the case. Therefore, the contact between the lithium ion battery and the liquid is suppressed.

(8) A battery pack for an electric vehicle according to any one of (1) to (4).
Each of the plurality of lithium-ion batteries has a continuous maximum charging rate of 40 C or more.

According to the above configuration, a maximum charging rate of 40 C or more can be realized as a battery pack for an electric vehicle, so that the battery pack for an electric vehicle can be charged in a shorter time.

(9) A battery pack for an electric vehicle according to any one of (1) to (4).
Each of the plurality of lithium ion batteries has a capacity of 5 Ah or more.

According to the above configuration, even when charging with a voltage of 60 V or less, the battery pack for the electric vehicle can be charged to the extent that the pure electric vehicle can run for normal purposes.

(10) A battery pack for an electric vehicle according to any one of (1) to (4).
Each of the plurality of lithium ion batteries has a capacity of 20 Ah or less.

According to the above configuration, even when charging with a voltage of 60 V or less, the battery pack for the electric vehicle can be charged to the extent that the pure electric vehicle can be driven for long-distance travel.

(11) A battery pack for an electric vehicle according to any one of (1) to (4).
The minimum charging voltage of the battery pack for an electric vehicle is 12V.

The battery pack for electric vehicles is charged with a charging voltage of 12V or higher. The battery pack for electric vehicles will not be charged at a voltage less than 12V. Each of the lithium-ion batteries connected in series can be charged with enough electric power to drive a pure electric vehicle.

1,21 Electric vehicle battery pack 11 Lithium-ion battery 12 Case 13 Electrical connector

Claims

A battery pack for electric vehicles used for pure electric vehicles.
The battery pack for an electric vehicle is
With multiple lithium-ion batteries
A case accommodating the plurality of lithium ion batteries and
An electrical connection connector that is connected to a mating connector provided on the vehicle body of the pure electric vehicle and transmits a current input / output to the vehicle body.
With
Each of the plurality of lithium-ion batteries has a continuous maximum charging rate of 10 C or more and is connected in series without being connected in parallel to each other, and the maximum charge of the battery pack for an electric vehicle corresponding to the voltage across the series connection. The voltage is 60 V or less.
The battery pack for an electric vehicle according to claim 1.
Each of the plurality of lithium ion batteries has a negative electrode containing at least one selected from the group consisting of spinel-type lithium titanate, niobium titanium-containing composite oxide, and graphite.
The battery pack for an electric vehicle according to claim 1 or 2.
A relay that is connected in series with the plurality of lithium ion batteries and cuts off the current flowing through the plurality of lithium ion batteries is provided.
The battery pack for an electric vehicle according to any one of claims 1 to 3.
The battery pack for an electric vehicle acquires at least one parameter of the current, voltage, or temperature detected from each of the plurality of lithium ion batteries, and based on the acquired at least one parameter, the said battery pack. It does not include a control device configured to change the voltage and / or current of at least one of the plurality of lithium ion batteries.
It ’s a pure electric vehicle,
The pure electric vehicle is
The battery pack for an electric vehicle according to any one of claims 1 to 4.
A mating connector configured to be connected to the electrical connector of the battery pack for an electric vehicle,
With the drive wheels
Motor control configured to control power supply from the battery pack for an electric vehicle to a motor via the mating connector and power supply from the motor to the battery pack for an electric vehicle via the mating connector. With the device
The motor is provided with the motor configured to drive the drive wheels with electric power supplied from the motor control device, while generating electric power by driving the drive wheels.
Of the plurality of lithium ion batteries, at least one parameter of the current, voltage or temperature detected from each of the plurality of lithium ion batteries is acquired, and based on the acquired at least one parameter, among the plurality of lithium ion batteries. It does not include a control device configured to change the voltage and / or current of at least one of the lithium-ion batteries.
The pure electric vehicle according to claim 5.
The pure electric vehicle is a saddle-mounted vehicle.
The saddle-mounted vehicle is
A steering bar handle provided so as to extend in the left-right direction of the saddle-mounted vehicle, and
Equipped with a saddle configured for the driver to sit across
As a lean vehicle, the driver who grips the bar handle at the time of turning is configured to turn by shifting the weight so as to lean inward of the curve.