Battery system for electric vehicle

Abstract

The present invention relates to a battery system for an electric vehicle, the system including: a main motor capable of regenerative braking; an input shaft rotatably driven by the main motor; an output shaft connected to the input shaft and receiving and outputting power of the main motor; and a power generation device connected to the output shaft and capable of regenerative braking during braking of the vehicle and constantly generating power during driving, wherein a battery pack is divided and provided in the battery system, a switching unit is provided to be connected to each battery pack, and each independent switching unit includes an inverter for connecting the main motor and the power generation device, thereby concurrently performing charging and discharging in the divided battery pack.

Description

Battery systems for electric vehicles

[0001] The present invention relates to a battery system for an electric vehicle, and more specifically, to a battery system for an electric vehicle capable of simultaneously executing charging and discharging by configuring a battery pack by dividing it, and capable of sequentially operating the divided battery packs alone or in combination depending on the operating purpose.

[0002] Recently, attempts have been made to use alternative power sources other than traditional internal combustion engines (hereinafter referred to as “engines”) as the power source for automobiles in order to reduce environmental pollution caused by automobile exhaust gases and to cope with limited petroleum resources.

[0003] A typical example is an electric vehicle. An electric vehicle is a car that uses electric energy stored in a battery to drive a motor and uses the driving force of the motor as a power source for all or part of the electric vehicle.

[0004] These electric vehicles are broadly categorized into pure electric vehicles that use only the electric energy of the battery as a power source, and hybrid electric vehicles (HEVs) that have an internal combustion engine and use the power generated by the engine to charge the battery or drive the vehicle.

[0005] An electric vehicle is used in a narrow sense to refer only to a purely electric vehicle to distinguish it from a hybrid electric vehicle. However, in the present invention, an electric vehicle is used in a broad sense encompassing purely electric vehicles and hybrid electric vehicles, to refer to any vehicle equipped with one or more batteries and in which the electric energy stored in the batteries is used as the driving force of the vehicle.

[0006] In such electric vehicles, in addition to the purpose of driving the vehicle, the drive motor also recovers and stores kinetic energy by performing regenerative braking when the vehicle decelerates.

[0007] That is, electric vehicles use part of the braking force to generate power when braking, and use the generated electric energy to charge the battery. By using part of the kinetic energy resulting from the vehicle's driving speed as energy required to drive the generator, they simultaneously achieve reduction in kinetic energy (i.e., reduction in driving speed) and generation of electric energy.

[0008] This type of braking method is called regenerative braking, and the generation of electric energy during regenerative braking can be achieved by driving the drive motor in reverse.

[0009] Regenerative braking control can improve an electric vehicle's mileage when braking. For hybrid electric vehicles, this can improve fuel efficiency and reduce noxious exhaust gas emissions.

[0010] Electric vehicles also feature hydraulic brake systems, which generate braking force through hydraulic pressure. Regenerative braking alone may not be sufficient to achieve adequate braking performance. Furthermore, since regenerative braking occurs only at the drive wheels connected to the motor, braking solely at the drive wheels cannot provide desirable vehicle dynamics control.

[0011] Conventional regenerative braking control methods / devices perform regenerative braking control in addition to the hydraulic braking force generated by the driver's brake pedal operation. Furthermore, the regenerative braking force is controlled to an amount independent of the magnitude of the required total braking force or the magnitude of the hydraulic braking force.

[0012] However, conventional regenerative braking has the disadvantage of having a limited power generation efficiency because the kinetic energy of the wheels is recovered as electric energy from the drive motor only when the drive motor is not operating, i.e. when the electric vehicle is driving downhill or braking.

[0013]

[0014] (Prior art literature)

[0015] (Patent Document)

[0016] Republic of Korea Patent No. 10-2274014

[0017] Accordingly, the present invention has been devised to solve the problems of the prior art as described above, and provides a battery system for an electric vehicle that is equipped with a power generation device that is installed at the output end of a transmission and generates power using the rotational inertia of a wheel and the surplus torque of a driving unit, and that is equipped with a battery pack in a divided manner so that charging and discharging can be performed simultaneously, and that the divided battery packs can be sequentially operated alone or in combination depending on the operating purpose.

[0018] In order to achieve the above-described object, the present invention provides a battery system for an electric vehicle, comprising: a main motor capable of regenerative braking; an input shaft driven by the main motor; an output shaft connected to the input shaft to receive and output power from the main motor; and a power generator connected to the output shaft to perform regenerative braking when the vehicle is braking and to generate power continuously while driving. The battery system comprises a battery pack divided into sections, a switching unit connected to each battery pack, and an inverter connected to each independent switching unit to connect the main motor and the power generator, thereby enabling simultaneous charging and discharging of the divided battery packs.

[0019] And, the switching unit is equipped with first and second switching units, and the first and second switching units are equipped with a plurality of switches corresponding to the divided battery packs, and each switch can be equipped to be connected to each battery pack in a one-to-one correspondence.

[0020] In addition, the divided battery packs may be arranged in a directionally oriented manner so that they are used and discharged sequentially from the first battery pack to the last battery pack, and charged sequentially from the last battery pack to the first battery pack.

[0021] Additionally, the split battery packs may be configured so that the last battery pack is only charged to 50-70% during the first charge.

[0022] In addition, the power generation device may include a power generation shaft that is connected to an output shaft and rotates in conjunction with it, and a power generation motor that generates power by the rotation of the power generation shaft.

[0023] In addition, the generator shaft may be equipped with a generator gear that is connected to the output shaft and rotates the generator shaft together with the output shaft.

[0024] In addition, the generator gear may be provided with a plurality of generator gears that are connected to the output shaft with different gear ratios while being idling-capable and are respectively connected to the output shaft, and a generation shift unit may be provided on the generation shaft to selectively connect a plurality of generator gears to the generation shaft while being axially movable while rotating together with the generation shaft, thereby enabling variable speed generation.

[0025] In addition, among the plurality of generator gears, one generator gear may be equipped to have an output shaft and a reduction ratio, and the other generator gear may be equipped to have an output shaft and an increase ratio.

[0026] According to the battery system for an electric vehicle of the present invention, a generator is provided at the output end of a transmission so that constant regenerative power generation can be performed by utilizing the rotational inertia of the wheels and the surplus torque of the driving unit, and since the battery pack is provided in a divided manner, charging and discharging can be performed simultaneously, and depending on the operational purpose, the divided battery packs can be sequentially operated alone or in combination, so that the energy efficiency due to regenerative power generation is excellent and maintenance is easy.

[0027] Figure 1 is a configuration diagram of an electric vehicle power generation device to which a battery system for an electric vehicle according to the present invention is applied.

[0028] Figure 2 is a diagram illustrating a circuit configuration of a battery system according to the present invention.

[0029] Figure 3 is a configuration diagram of a battery pack according to the present invention.

[0030] Figure 4 is a drawing showing the charging and discharging structure of a battery pack according to the present invention.

[0031] Figure 5 is a block diagram illustrating a control system of a battery system for an electric vehicle according to the present invention.

[0032] FIG. 6a and FIG. 6b are diagrams each showing the constant power generation flow of the main motor in the low-speed and high-speed sections during driving in a transmission to which a battery system according to the present invention is applied.

[0033] FIG. 7a and FIG. 7b are diagrams showing the flow of regenerative power generation in low-speed and high-speed sections during regenerative braking in a transmission to which a battery system according to the present invention is applied, respectively.

[0034] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0035] The terms used in the present invention are terms defined in consideration of their functions in the present invention, and may vary depending on the intention or custom of the user or operator. Therefore, the definitions of these terms should be interpreted as meanings and concepts that are consistent with the technical aspects of the present invention.

[0036] In addition, the embodiments of the present invention do not limit the scope of the present invention, but are merely exemplary matters of the components presented in the claims of the present invention, and are embodiments that include components that are included in the technical idea throughout the specification of the present invention and can be replaced as equivalents in the components of the claims.

[0037] Additionally, the optional terms in the examples below are used to distinguish one component from another, and the components are not limited by the terms.

[0038] Accordingly, in describing the present invention, detailed descriptions of related known technologies that may unnecessarily obscure the gist of the present invention are omitted.

[0039]

[0040] The attached drawings 1 to 7b are drawings illustrating specific embodiments of a battery system for an electric vehicle according to the present invention.

[0041] Here, in this embodiment, the power generation device and battery system are explained as an example of being applied to an electric vehicle, but it is to be noted in advance that the system can be applied not only to electric vehicles but also to hybrid electric vehicles.

[0042] The battery system for an electric vehicle according to the present invention is described by exemplifying a form configured to be connected to a transmission device of an electric vehicle as illustrated in FIG. 1, but the transmission device of the electric vehicle according to the present embodiment may have various forms of transmission devices in addition to the embodiment illustrated in FIG. 1, and the battery system for an electric vehicle according to the present invention may be applied by connecting to output terminals of such various transmission devices.

[0043] In addition, the transmission of an electric vehicle may be further equipped with a power generation device capable of constant regenerative power generation by utilizing the rotational inertia of the wheels and the surplus torque of the driving unit, which is installed at the output end of the transmission device.

[0044] In particular, the power generation device includes a main motor (100) capable of regenerative braking, an input shaft (200) that is rotationally driven by the main motor (100), an output shaft (300) that is connected to the input shaft (200) and receives and outputs power from the main motor (100), and a power generation motor (500) that is connected to the output shaft (300) and is capable of generating power continuously even when the vehicle is driving as well as performing regenerative braking when the vehicle is braking. This power generation device will be described in detail below.

[0045] Meanwhile, a transmission device having a power generation device as described above is configured with a battery system according to the present invention, and as illustrated in FIG. 1, the battery system comprises a plurality of divided battery packs (600) (610) (620), a switching unit (640) (650) configured to connect the divided battery packs (600) (610) (620) to the main motor (100) and the generator motor (500) to be described later, respectively, and an inverter (660) (670) configured to connect the main motor (100) and the generator motor (500) to each switching unit (640) (650), respectively, so that charging and discharging can be performed simultaneously on the divided battery packs (600) (610) (620).

[0046] Here, the divided battery packs (600) (610) (620) can be divided and configured without limitation in number, but in this embodiment, three battery packs divided into a first battery pack (600), a second battery pack (610), and a third battery pack (620) are described as an example.

[0047] And, as shown in FIG. 3, the first, second, and third battery packs (600)(610)(620) are provided with a plurality of batteries (600a)(610a)(620a) constituting each battery pack, and specifically, as an example, a plurality of batteries (600a)(610a)(620a) are connected in series and parallel in three vertical rows and sixteen horizontal rows, but in addition, the battery packs can be configured by being divided into a plurality of Sub-Packs that are connected in series and parallel in various vertical and horizontal rows to suit various required capacities, so that when the battery system malfunctions, only the battery pack (600)(610)(620) and battery (600a)(610a)(620a) that caused the malfunction can be replaced, and thus maintenance of the battery packs (600)(610)(620) is easily performed.

[0048] In addition, the switching unit is exemplified by two switching units consisting of a first switching unit (640) and a second switching unit (650), and each of the first and second switching units (640) (650) may be configured with three switches (640a) (640b) (640c) (650a) (650b) (650c) installed independently.

[0049] In particular, each switch configured in the first and second switching units (640)(650) is connected to each of the divided battery packs (600)(610)(620) in a one-to-one correspondence as a first switch (640a)(650a), a second switch (640b)(650b), and a third switch (640c)(650c), as illustrated in FIG. 2.

[0050] That is, the first switch (640a) (650a) of each switching unit (640) (650) is connected to the first battery pack (600), the second switch (640b) (650b) is connected to the second battery pack (610), the third switch (640c) (650c) is connected to the third battery pack (620), and the first, second, and third battery packs (600) (610) (620) are each provided to be grounded.

[0051] And, the inverter is exemplified by two inverters, a first inverter (660) and a second inverter (670), and the first inverter (660) is provided to connect the main motor (100) and the first switching unit (640), and the second inverter (670) is provided to connect the generator motor (500) and the second switching unit (650).

[0052] These first and second inverters (660)(670) are power conversion devices that can convert the direct current power of each battery pack (600)(610)(620) into alternating current power and supply it to each motor (100)(500), or convert the alternating current power generated by each motor (100)(500) into direct current power and supply it to each battery pack (600)(610)(620) and store it.

[0053] That is, the first and second inverters (660)(670) are connected to the main motor (100) and the generator motor (500) with multiple cables, respectively, and are connected to the first and second switching units (640)(650) with a single cable, respectively, and the first and second switching units (640)(650) are separately grounded and provided.

[0054] Meanwhile, the divided battery pack (600) (610) (620) configured as described above is configured so that charging and discharging are controlled by a control system.

[0055] To this end, the divided battery packs (600)(610)(620) are connected in a directional manner from the first battery pack (600) to the third battery pack (620), and the divided battery packs (600)(610)(620) by the control system are used and discharged in the order of the first battery pack (600) to the second battery pack (610) and the third battery pack (620), and the charging is performed in the order of the third battery pack (620) to the first battery pack (600) and the second battery pack (610).

[0056] In this way, by discharging and charging one battery pack continuously with a time difference as a term in the sequence between discharging and charging of the divided battery packs (600)(610)(620), discharging and charging can be performed simultaneously, and depending on the operational purpose, the divided battery packs (600)(610)(620) can be used sequentially, singly or in combination.

[0057] In addition, the third battery pack (620) may be designed and equipped to be charged only up to 50-70% during the first charge of the divided battery packs (600)(610)(620), but more preferably, it may be designed and equipped to be charged only up to 50%. This is because, due to the nature of electric vehicles, power generation (charging) is constantly performed by repetitive regenerative braking, thereby providing a charging margin to the third battery pack (620), which is charged first during charging, so that it can maintain a state in which charging is always possible.

[0058] In addition, the control system for controlling the discharge and charge of the divided battery pack (600)(610)(620) as described above includes a transmission control unit (TCU) for controlling a transmission device, a battery management system (BMS) for managing the divided battery pack (600)(610)(620), and a vehicle control unit (VCU) for controlling the transmission control unit and the battery management unit, as illustrated in FIG. 5.

[0059] The transmission control unit as described above controls the main motor (100) and the generator motor (500) of the transmission, and the battery management unit is provided to control the first and second switching units (640) (650) and the driving discharge and charging sequence of the first, second, and third battery packs (600) (610) (620).

[0060] And, the vehicle control unit receives input values ​​from an accelerator pedal, a brake pedal, a GPS, a gradient sensor, a torque sensor, a vehicle speed sensor, etc., and controls the main motor (100) and the generator motor (500) through a transmission control unit, and controls the driving discharge and charging of the first, second, and third battery packs (600) (610) (620) through a battery management unit.

[0061]

[0062] Meanwhile, the battery system as described above is configured in the transmission of an electric vehicle, and a power generation device may be further configured in the transmission.

[0063] First, as shown in Fig. 1, the transmission includes a main motor (100) which is a power source that supplies power, an input shaft (200) that receives power from the main motor (100) and is rotated, and an output shaft (300) that is connected to the input shaft (200) and receives power from the input shaft (200) and outputs power.

[0064] A power generator is connected to the output shaft (300) and the main motor (100), so that power generation is possible at all times, even during driving, as well as during regenerative braking.

[0065] Here, the main motor (100) is configured with a stator (coil) and a rotor (an electromagnet or, in the present invention, an “input shaft (200)”) inside it. When power is supplied to the stator and current flows, the rotor (input shaft (200)) rotates by the magnetic force formed in the stator, and the electrical energy is converted into kinetic energy. Conversely, when the rotor (input shaft (200)) rotates by an external force, i.e., the rotational force of the wheel, an induced current is generated in the stator, and the kinetic energy is converted into electrical energy.

[0066] Accordingly, the main motor (100) has not only the unique function of a motor that rotates the input shaft (200) when power is supplied, but also the function of a generator that converts the inertial force (rotational force) of the wheel, i.e., kinetic energy, into electrical energy to generate electricity.

[0067] An input shaft (200) is connected to the center of the main motor (100) and is provided to rotate, and an input gear (210) fixed to the input shaft (200) is installed and is provided to rotate integrally with the input shaft (200).

[0068] In addition, the output shaft (300) is provided with a transmission gear (310) that is engaged with the input gear (210) of the input shaft (200), and an output gear (320) that is spaced apart from the transmission gear (310) and engages with the generator gear (520) of the generator to be described later.

[0069] Accordingly, the transmission gear (310) is rotated integrally with the output shaft (300) by the rotation of the input gear (210), and the output gear (320) is rotated integrally with the output shaft (300) by the rotation of the output shaft (300).

[0070] At this time, the transmission gear (310) is connected to the input gear (210) to have a reduction ratio, and the output gear (320) is provided with a differential gear of a differential device (400) configured in the electric vehicle.

[0071] And, a power generation device is connected to the output gear (320) of the output shaft (300), and the power generation device includes a power generation shaft (510) that is connected to the output shaft (300) and rotates in conjunction with it, and a power generation motor (500) that generates power by rotating together with the power generation shaft (510) due to the rotation of the power generation shaft (510).

[0072] In addition, a single generator gear (520) that is connected to the output shaft (300) and rotates the generator shaft (510) synchronously with the output shaft (300) may be fixedly provided on the generator shaft (510), but in the following embodiment, a case in which a plurality of generator gears (520)(530) are provided on the generator shaft (510) is described as an example.

[0073] That is, in the present embodiment, as illustrated in FIG. 1, a plurality of generator gears (520)(530) are provided, each of which is connected to the output shaft (300) with different gear ratios and is connected to the generator shaft (510) in a state where no-load rotation, i.e., idling, is possible, and a power generation shift unit (540) is provided between the generator gears (520)(530) so that the generator shaft (510) can rotate together with the generator shaft (510) and move in the axial direction, thereby selectively connecting the plurality of generator gears (520)(530) to the generator shaft (510) to enable variable-speed power generation.

[0074] In particular, the power generation shaft (510) is equipped with a plurality of generator gears, i.e., first and second generator gears (520) (530), and the first and second generator gears (520) (530) are respectively equipped to be idling-capable of being coupled to the power generation shaft (510), so that the first and second generator gears (520) (530) and the power generation shaft (510) are equipped to be capable of independent rotation without interfering with each other.

[0075] In addition, the output shaft (300) is further equipped with a separate sub-gear, that is, a parking brake gear (330), in addition to the transmission gear (310) and the output gear (320), and the transmission gear (310), the output gear (320), and the parking brake gear (330) are fixedly installed on the output shaft (300) and are provided to rotate together with the output shaft (300).

[0076] Accordingly, the transmission gear (310) as described above is provided in a meshed manner with the input gear (210) of the input shaft (200), the output gear (320) is provided in a meshed manner with the first generator gear (520) of the generator shaft (510), and the parking brake gear (330) is provided in a meshed manner with the second generator gear (530) of the generator shaft (510).

[0077] In addition, the first and second generator gears (520)(530) are provided to have different gear ratios. The first generator gear (520) is formed to have a larger diameter and more teeth than the output gear (320) so as to have a reduction ratio with the output gear (320) (first generator gear (520) > output gear (320)), and the second generator gear (530) is formed to have a smaller diameter and fewer teeth than the parking brake gear (330) so as to have an increase ratio with the parking brake gear (330) (second generator gear (530) < parking brake gear (330)).

[0078] Accordingly, in the low-speed section of the electric vehicle, the second generator gear (530) and the parking brake gear (330) are connected to enable power transmission by the generator shift unit (540), thereby maximizing the power generation efficiency in the low-speed section, and in the high-speed section of the electric vehicle, the first generator gear (520) and the output gear (320) are connected to enable power transmission by the generator shift unit (540), thereby preventing overload of the motor and increasing the power generation efficiency.

[0079] In addition, the above-described power generation shaft (510) is connected to the center of the power generation motor (500) and is provided to rotate, and the power generation motor (500) is configured with a stator (coil) and a rotor (electromagnet) inside it, just like the main motor (100), but in the present invention, the power generation shaft (510) is provided as a rotor.

[0080] This generator motor (500) is mainly operated as a generator rather than as a motor. When the generator shaft (510), which is a rotor, is rotated by the inertial force (rotational force) of the wheel, an induced current is generated in the stator, and the kinetic energy is converted into electrical energy and stored.

[0081]

[0082] The operational relationship of a battery system configured with a power generation device as described above is described.

[0083] First, when the electric vehicle is driven, as shown by the arrows in FIGS. 6A and 6B, the main motor (100) is operated, and the power of the main motor (100) is transmitted to each wheel through the input gear (210) that rotates integrally with the input shaft (200) -> transmission gear (310) -> output shaft (300) -> output gear (320) -> differential device (400), thereby driving the electric vehicle.

[0084] At this time, the electric energy consumption during driving of the electric vehicle, that is, the driving discharge, is used and discharged in the order of the first battery pack (600) -> second battery pack (610) -> third battery pack (620), and the electric energy of each battery pack (600)(610)(620) is output through the corresponding switch (640a)(640b)(640c) of the first switching unit (640) connected thereto, and the electric energy of the battery pack (600)(610)(620) that is output is converted from high-voltage direct current to alternating current while passing through the first inverter (660) and supplied as electric power (power) to the main motor (100).

[0085] And, the power of the main motor (100) is mostly used as the power required for the initial driving of the electric vehicle, but after the electric vehicle accelerates to a certain speed or higher, the power of the main motor (100) has surplus energy remaining even after rotating the wheels due to the inertial force of the wheels.

[0086] The surplus energy of the main motor (100) was previously consumed as rotational power for rotating the wheels, but in the present invention, the generator gear (520) meshed with the output gear (320) rotates due to the rotation of the output gear (320), and as the generator shaft (510) rotates due to the rotation of the generator gear (520), electric energy is generated in the generator motor (500), so that the surplus energy of the main motor (100), which was previously consumed and discarded, is converted into electric energy and stored in the battery system.

[0087] In particular, the electric energy generated from the generator motor (500) is converted from alternating current to high-voltage direct current and supplied through the second inverter (670), and is supplied to the corresponding battery pack (600) (610) (620) through each switch (650a) (650b) (650c) of the second switching unit (650) to be charged. At this time, the battery pack (600) (610) (620) is charged sequentially in the order of the third battery pack (620) -> first battery pack (600) -> second battery pack (610).

[0088] At this time, the ideal initial charge state of the battery packs (600)(610)(620) is that the third battery pack (620), which is the first to be regeneratively charged during driving, is initially charged only up to 50-70%, and the first and second battery packs (600)(610) start driving at an initial full charge state of 100%. During driving, the first and second battery packs (600)(610) are sequentially discharged, and then the charging mode is changed to regenerative charging again, and when the third battery pack (620) is fully charged through regenerative charging during driving, it is changed to discharge mode and discharges sequentially. At this time, the discharge order of the battery packs (600)(610)(620) is sequentially discharged in the following order: first battery pack (600) → second battery pack (610) → third battery pack (620) → first battery pack (600).

[0089] Accordingly, when the main motor (100) is in operation, the differential device (400) and the generator gear (520) are driven to rotate simultaneously by the rotating output gear (320), thereby rotating the wheels and converting the remaining energy of the main motor (100) into electric energy without discharging it, thereby enabling constant power generation.

[0090] In addition, when the electric vehicle is driving and power is not supplied to the main motor (100), that is, when the electric vehicle is driving downhill or decelerating or braking, only the inertial force of the wheels (inertial energy of the vehicle) exists.

[0091] Then, as shown by the arrows in FIGS. 3, 7a and 7b, as the output gear (320), the output shaft (300), the input gear (210) and the input shaft (200) are rotated by the inertial force of the wheel, regenerative braking is performed in the main motor (100) that is not driven due to the power being cut off, which converts the inertial force of the wheel into electric energy, and at the same time, as the generator gear (520) and the generator shaft (510) are rotated by the output gear (320), the generator motor (500) also converts the inertial force of the wheel into electric energy, which is stored and charged in each battery pack (600) (610) (620) in the charging order described above, so that the power generation efficiency and energy efficiency can be improved.

[0092] Meanwhile, in the case where the driving speed of the electric vehicle as described above is in a low-speed section, as shown in FIG. 6a, the power generation shift unit (540) is moved toward the second power generation gear (530) on the power generation shaft (510) to connect the second power generation gear (530) and the power generation shaft (510) in a state where power transmission is possible, thereby synchronizing the second power generation gear (530) with the power generation shaft (510).

[0093] In addition, the second generator gear (530) is rotated synchronously with the rotation of the parking brake gear (330) that rotates together with the output shaft (300), and since the second generator gear (530) and the parking brake gear (330) are connected to have an increase ratio, they are rotated at an increase speed to increase (rise) the rotation rpm of the generator shaft (510).

[0094] Accordingly, as the rotational rpm of the power generation shaft (510) increases despite the low-speed driving of the electric vehicle, the power generation efficiency of the power generation motor (500) that is constantly generating power as described above is maximized, thereby improving the power generation efficiency.

[0095] Of course, when the second generator gear (530) and the parking brake gear (330) rotate synchronously as described above, the first generator gear (520) and the output gear (320) also rotate synchronously, but at this time, the first generator gear (520) is connected to the generator shaft (510) in a no-load state, so it rotates idling on the generator shaft (510).

[0096] And, when the driving speed of the electric vehicle reaches the high-speed section, the power generation shift unit (540) moves toward the first power generation gear (520) on the power generation shaft (510), thereby connecting the first power generation gear (520) and the power generation shaft (510) in a state where power transmission is possible, thereby synchronizing the first power generation gear (520) with the power generation shaft (510).

[0097] The first generator gear (520) rotates synchronously with the rotation of the output gear (320) that rotates together with the output shaft (300), and since the first generator gear (520) and the output gear (320) are connected to have a reduction ratio, they rotate at a reduced speed to lower (decelerate) the rotation rpm of the generator shaft (510).

[0098] In this way, by reducing the rotational rpm of the power generation shaft (510) during high-speed driving of the electric vehicle, it is possible to prevent overload of the power generation motor (500) that is constantly generating power while increasing power generation efficiency.

[0099] In this case, when the first generator gear (520) and the output gear (320) rotate synchronously, the second generator gear (530) and the parking brake gear (330) also rotate synchronously, but since the second generator gear (530) is connected to the generator shaft (510) in a no-load state, it rotates idling on the generator shaft (510).

[0100] Accordingly, when the main motor (100) is in operation, the differential device (400) and the first and second generator gears (520) (530) are selectively connected and driven to rotate by the output gear (320) that rotates, thereby rotating the wheels and transmitting the remaining surplus energy of the main motor (100) to the generator motor (500) in a speed range, that is, by increasing or decreasing the speed, to generate electric energy without discharging it.

[0101] Meanwhile, even when the main motor (100) is not operating after the electric vehicle is driven and only the rotational force of the wheels is applied, as shown by the arrows in FIGS. 7a and 7b, the rotational force of the wheels, that is, the inertial force, is selectively transmitted to the power generation motor (500) by changing the speed according to the change in low and high speeds as in the operation of the main motor (100) described above, thereby improving the power generation efficiency, and at the same time, regenerative braking is performed in the main motor (100) as described above.

[0102]

[0103] Although the present invention has been described in detail through specific examples, this is intended to specifically explain the present invention, and the present invention is not limited thereto, and it is clear that modifications and improvements can be made by those skilled in the art within the technical spirit of the present invention.

[0104] All simple modifications or changes of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

[0105]

[0106] (Explanation of symbols)

[0107] 100: Main motor 200: Input shaft

[0108] 210: Input gear 300: Output shaft

[0109] 310: Transmission gear 320: Output gear

[0110] 330: Parking brake gear 400: Differential gear

[0111] 500: Generator motor 510: Generator shaft

[0112] 520,530: Generator gear 540: Generator shift unit

[0113] 600,610,620: Battery pack 610a,620a,630a: Battery

[0114] 640,650: Switching unit 660,670: Inverter

Claims

1. A battery system for an electric vehicle including a main motor capable of regenerative braking, an input shaft that is rotated by the main motor, an output shaft that is connected to the input shaft and receives and outputs power from the main motor, and a power generator that is connected to the output shaft and can generate power continuously while the vehicle is driving as well as perform regenerative braking when the vehicle is braking. The battery system is equipped with divided battery packs. Each battery pack is equipped with a switching unit connected to it. Each independent switching unit is equipped with an inverter that connects the main motor and the generator. A battery system for electric vehicles capable of simultaneously charging and discharging a divided battery pack.

2. In claim 1, A battery system for an electric vehicle, wherein the switching unit is provided with first and second switching units, the first and second switching units are provided with a plurality of switches corresponding to divided battery packs, and each switch is connected to each battery pack in a one-to-one correspondence.

3. In claim 1, A battery system for an electric vehicle in which the divided battery packs are arranged in a directionally aligned manner, and are used and discharged sequentially from the first battery pack to the last battery pack, and are charged sequentially from the last battery pack to the first battery pack.

4. In claim 3, An electric vehicle battery system in which, when charging the divided battery packs for the first time, the last battery pack is charged only to 50-70% of its capacity, rather than being fully charged, to ensure that there is enough charging space to allow for immediate charging when driving begins.

5. In claim 1, A battery system for an electric vehicle, which includes a generator shaft that is connected to an output shaft and rotates in conjunction with the generator motor that generates power by the rotation of the generator shaft.

6. In claim 5, A battery system for an electric vehicle, in which a generator gear is installed on the generator shaft and connected to the output shaft to rotate the generator shaft together with the output shaft.

7. In claim 6, The generator gear is equipped with multiple generator gears that are connected to the output shaft with different gear ratios and are connected to the generator shaft in an idling state. A battery system for an electric vehicle, wherein a power generation shift unit is provided on a power generation shaft so as to be movable in the axial direction while rotating together with the power generation shaft, and a plurality of power generation gears can be selectively connected to the power generation shaft to enable variable speed power generation.

8. In claim 7, An electric vehicle battery system, wherein one of the plurality of generators is equipped with an output shaft and a reduction gear ratio, and the other generator is equipped with an output shaft and an increase gear ratio.

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