Electric vehicle power supply device and two-wheeled electric vehicle

Abstract

This utility model provides a power supply device for an electric vehicle and a two-wheeled electric vehicle. The power supply device for the electric vehicle is characterized by comprising a first power supply unit and a second power supply unit. The first power supply unit is a lead-acid battery, and its battery capacity is greater than half of the total battery capacity of the power supply device. The second power supply unit is connected in parallel with the first power supply unit, and its discharge rate is greater than that of the first power supply unit. This power supply device offers high safety, low cost, and strong discharge capability.

Description

Technical Field

[0001] This application relates to the field of battery and electric vehicle technology, and more particularly to a power supply device for an electric vehicle and a two-wheeled electric vehicle. Background Technology

[0002] Two-wheeled electric vehicles or electric motorcycles (hereinafter collectively referred to as two-wheeled electric vehicles) are currently experiencing a period of rapid demand growth. People have many demands regarding the performance, safety, and cost of two-wheeled electric vehicles. Currently, batteries account for a large proportion of the cost of two-wheeled electric vehicles, and they also have a significant impact on the safety of these vehicles. Existing batteries for two-wheeled electric vehicles are mainly divided into two types: lithium batteries and lead-acid batteries. Due to the inherent tendency of lithium batteries to spontaneously combust and explode, and their high cost, most two-wheeled electric vehicles use lead-acid batteries. Lead-acid batteries have good chemical stability and are resistant to overcharging and over-discharging, making them a relatively safe battery type. They also have the advantage of extremely low cost. However, compared to lithium batteries, lead-acid batteries have lower energy density, lower charge / discharge rates, and poorer power performance, which significantly affects the driving performance of two-wheeled electric vehicles.

[0003] In addition, the limited space and weight of two-wheeled electric vehicles result in a limited amount of battery energy that can be carried, which leads to significant bottlenecks in their range and acceleration capabilities. Utility Model Content

[0004] In view of this, embodiments of this application provide a power supply device for an electric vehicle and a two-wheeled electric vehicle to at least partially solve the above-mentioned problems.

[0005] According to a first aspect of the embodiments of this application, a power supply device for an electric vehicle is provided, which includes a first power supply unit and a second power supply unit. The first power supply unit is a lead-acid battery, and the battery capacity of the first power supply unit is greater than half of the total battery capacity of the power supply device. The second power supply unit is connected in parallel with the first power supply unit, and the discharge rate of the second power supply unit is greater than the discharge rate of the first power supply unit.

[0006] Optionally, the second power supply unit is a lithium battery.

[0007] Optionally, the battery capacity of the second power supply unit is less than or equal to one-third of the battery capacity of the first power supply unit, and the ratio of the discharge rate of the second power supply unit to the discharge rate of the first power supply unit is greater than or equal to 3:1.

[0008] Optionally, the power supply device also includes an output bus, with the first power supply unit and the second power supply unit connected in parallel on the output bus. The output bus is used to be directly or indirectly connected to the drive motor of the electric vehicle, and all or part of the electrical energy recovered by the kinetic energy of the drive motor is transmitted to the second power supply unit through the output bus.

[0009] Optionally, the length of the output bus between the first power supply unit and the motor controller of the drive motor is a first conductor distance, and the length of the output bus between the second power supply unit and the motor controller of the drive motor is a second conductor distance, wherein the first conductor distance is greater than or equal to the second conductor distance.

[0010] Optionally, the full-charge voltage of the first power supply unit is equal to the full-charge voltage of the second power supply unit, or the difference between the full-charge voltage of the first power supply unit and the full-charge voltage of the second power supply unit is less than a set error value, and the set error value is less than or equal to 5V.

[0011] Optionally, the second power supply unit includes a battery body and a second power supply protection board. The battery body is connected to the second power supply protection board, and the positive and negative output terminals of the second power supply protection board are connected in parallel with the first power supply unit.

[0012] Optionally, the second power supply protection board is used to control the second power supply unit to only discharge when the total voltage of the lithium battery is greater than or equal to the first voltage threshold; and / or, the second power supply protection board is used to control the second power supply unit to only charge when the total voltage of the lithium battery is less than or equal to the second voltage threshold, wherein the second voltage threshold is less than the first voltage threshold.

[0013] According to another aspect of this application, a two-wheeled electric vehicle is provided, which includes a drive motor and a power supply device for the electric vehicle, wherein the drive motor is electrically connected to the power supply device, and both the first power supply section and the second power supply section of the power supply device output drive power to the drive motor.

[0014] Optionally, the two-wheeled electric vehicle also includes a first and a second housing space that are isolated from each other, with the first power supply unit disposed in the first housing space and the second power supply unit disposed in the second housing space; or, the two-wheeled electric vehicle also includes a battery housing space, with both the first and second power supply units disposed in the battery housing space.

[0015] According to the power supply device scheme for electric vehicles provided in this application embodiment, the power supply device has the advantages of low cost and high reliability. Furthermore, under the same discharge capacity and range, the power supply device of this embodiment occupies less space and weighs less. This is because the first power supply unit is a lead-acid battery, which has relatively low cost and high stability and safety. Using it as the main power supply unit, and because the battery capacity of the first power supply unit is greater than half of the total battery capacity of the power supply device, it provides most of the electricity required for the electric vehicle's range, ensuring low overall cost and high reliability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0017] Figure 1 A circuit diagram of the power supply device for an electric vehicle according to an embodiment of the present invention is shown.

[0018] 10. First power supply unit; 20. Second power supply unit; 21. Battery body; 22. Second power supply protection board; 40. Output bus; 30. Motor controller; 50. Drive motor. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this application.

[0020] The specific implementation of the embodiments of this application will be further described below with reference to the accompanying drawings.

[0021] Reference Figure 1 The diagram shows a circuit diagram of a power supply device for an electric vehicle according to an embodiment of the present invention. This power supply device is used to supply power to an electric vehicle (especially a two-wheeled electric vehicle, including but not limited to an electric bicycle or electric motorcycle) as its power battery.

[0022] In this embodiment, the power supply device of the electric vehicle includes a first power supply unit 10 and a second power supply unit 20. The first power supply unit 10 is a lead-acid battery, and the battery capacity of the first power supply unit 10 is greater than half of the total battery capacity of the power supply device. The second power supply unit 20 is connected in parallel with the first power supply unit 10, and the discharge rate of the second power supply unit 20 is greater than the discharge rate of the first power supply unit 10.

[0023] This power supply device has the advantages of low cost and high reliability. Furthermore, under the same discharge capacity and range, the power supply device in this embodiment occupies less space and weighs less. This is because the first power supply unit 10 is a relatively low-cost, stable, and safe lead-acid battery. Using it as the main power supply unit, and because the battery capacity of the first power supply unit 10 is greater than half of the total battery capacity of the power supply device, it provides most of the electricity required for the electric vehicle's range, ensuring low overall cost and high reliability.

[0024] To compensate for the relatively weak discharge capacity of lead-acid batteries, this embodiment includes a second power supply unit 20. This second power supply unit 20 uses a power supply unit with a higher discharge rate than the first power supply unit 10 as an auxiliary power supply unit, giving the power supply device a stronger short-time discharge capability. When applied to electric vehicles, this can improve the vehicle's acceleration. Because the battery capacity of the second power supply unit 20 is less than half that of the power supply device, its size and weight are also smaller. Even though its safety is lower than that of lead-acid batteries, it will not have a significant adverse impact on the overall safety of the power supply device, making the power supply device safer than batteries with the same maximum discharge capacity.

[0025] In some preferred examples, the second power supply unit 20 is a lithium battery. Compared with lead-acid batteries, lithium batteries have higher energy density and discharge capacity (also known as power density), but their safety is relatively lower. In this embodiment, a safer lead-acid battery is used as the main power supply unit, and a lithium battery with stronger but smaller discharge capacity is used to improve the instantaneous maximum discharge capacity. This balances safety without significantly increasing the risk of spontaneous combustion of the power supply device.

[0026] The advantages of this power supply device are illustrated below with a specific example:

[0027] Taking a typical 100km range two-wheeled electric motorcycle as an example, the total battery energy required is approximately 5kWh. Of this, 4.7kWh uses lead-acid batteries (priced at approximately 300 RMB / kWh), while the remaining 0.3kWh uses high-discharge-rate lithium batteries (priced at approximately 1300 RMB / kWh). This results in a total battery cost of 1800 RMB. In contrast, if all batteries were high-discharge-rate lithium batteries, the cost would be 6500 RMB. Therefore, the cost of the power supply device in this embodiment is significantly lower than that of lithium batteries, and lead-acid batteries alone cannot achieve the designed discharge rate.

[0028] In terms of discharge capacity, a 0.3kWh lithium-ion battery can easily achieve an output of 100A. Combined with the approximately 20A output of a lead-acid battery, a total output of 120A can be achieved. For an 80V power supply, the total power reaches 9.6kW, which is more than enough to meet the power requirements of a high-performance two-wheeled electric motorcycle. Although a lithium-ion battery alone can easily achieve a discharge capacity exceeding 120A, it is more than sufficient for a two-wheeled electric motorcycle. If a high-capacity lithium-ion battery is used, although the cost is reduced, it is still higher than that of a lead-acid battery, and even a high-capacity lithium-ion battery would struggle to achieve a discharge of 120A.

[0029] In terms of safety, lead-acid batteries are extremely difficult to explode and burn. For lithium batteries, whether power type or capacity type, the power of explosion and combustion is directly related to the battery capacity. The capacity of the power lithium battery using the solution in this embodiment is only 6% of the capacity of the traditional all-lithium battery solution. If an uncontrollable combustion and explosion event occurs, the degree of danger is far less than that of the traditional lithium battery solution.

[0030] Of course, in other embodiments, the second power supply unit 20 may be other structures such as capacitors connected in parallel, which can also achieve the effect of improving the discharge capability of the power supply device.

[0031] It should be noted that although the above example illustrates the effect using a battery capacity of 4.7 kWh for the first power supply unit 10 and 0.3 kWh for the second power supply unit 20, this does not limit the ratio of the battery capacities of the first power supply unit 10 and the second power supply unit 20. In some preferred examples, the battery capacity of the second power supply unit 20 is less than or equal to one-third of the battery capacity of the first power supply unit 10, and the ratio of the discharge rate of the second power supply unit 20 to the discharge rate of the first power supply unit 10 is greater than or equal to 3:1. This balances cost, discharge capacity, and safety.

[0032] For example, the discharge rate of a lead-acid battery can be from 0.1C to 5C, such as a continuous discharge rate of 0.5C and an instantaneous maximum discharge rate of 3C. The discharge rate of a lithium battery can be from 20C to 50C, such as a continuous discharge rate of 30C and an instantaneous discharge rate of 50C.

[0033] Preferably, the ratio of the discharge rate of the second power supply unit 20 to the discharge rate of the first power supply unit 10 is greater than or equal to 5:1 or 4:1.

[0034] Optionally, the power supply device further includes an output bus 40. The first power supply unit 10 and the second power supply unit 20 are connected in parallel on the output bus 40. The output bus 40 is used to directly or indirectly connect to the drive motor 50 of the electric vehicle, and all or part of the electrical energy recovered by the drive motor 50 is transmitted to the second power supply unit 20 through the output bus 40. In this embodiment, the drive motor 50 is used to drive the wheels of the electric vehicle to rotate, and the drive motor 50 is a three-phase AC motor. The output bus 40 is used to transmit the DC power output by the first power supply unit 10 and the second power supply unit 20. Therefore, the output bus 40 and the drive motor 50 can be connected through a motor controller 30 to convert the DC power into AC power to power the drive motor 50. Of course, the motor controller 30 can also have other control functions, which are not limited.

[0035] In other embodiments, a DC motor may also be used as the drive motor 50, and the output bus 40 may be directly connected to the drive motor 50, without limitation.

[0036] Preferably, to further improve the driving range, the kinetic energy of the electric vehicle during deceleration or braking can be converted into electrical energy using the drive motor 50 (or other structure) and then recovered in the reverse direction. In some examples, the recovered electrical energy can be simultaneously transferred to the first power supply unit 10 and the second power supply unit 20. However, since the second power supply unit 20 has lower internal resistance, it has greater recovery capacity. Therefore, most of the electrical energy is transferred to the second power supply unit 20, and the remaining electrical energy is transferred to the first power supply unit 10.

[0037] Of course, in other embodiments, the recovered electrical energy can be controlled by a power supply control board or the like to be delivered only to the first power supply unit 10 or the second power supply unit 20.

[0038] Preferably, in order to further improve the efficiency of kinetic energy recovery, the length of the output bus 40 between the first power supply unit 10 and the motor controller 30 of the drive motor 50 is the first wire distance, and the length of the output bus 40 between the second power supply unit 20 and the motor controller 30 of the drive motor 50 is the second wire distance, wherein the first wire distance is greater than or equal to the second wire distance.

[0039] In some preferred embodiments, the wire distance between the second power supply unit 20 and the motor controller 30 is shorter, so that the distance from which the kinetic energy recovery energy is transmitted to the second power supply unit 20 is shorter than that of the first power supply unit 10, and the second power supply unit 20 can absorb more energy when there is a large energy surge.

[0040] Of course, it is also possible to place the first power supply unit 10 and the second power supply unit 20 together, with the wires of both having the same length.

[0041] Optionally, the full-charge voltage of the first power supply unit 10 is equal to the full-charge voltage of the second power supply unit 20, or the difference between the full-charge voltage of the first power supply unit 10 and the full-charge voltage of the second power supply unit 20 is less than a set error value, which is less than or equal to 5V. This ensures stable output after the two are connected in parallel.

[0042] In this example, the full-charge voltage ranges from 48V to 88V to ensure it can be used as a power battery. For example, in some cases, the maximum voltage of a lead-acid battery when fully charged is 88V, and the maximum voltage of a lithium battery is 85V. After starting to discharge, the voltage of both can drop to 84V in a short time.

[0043] To further enhance safety, the second power supply unit 20 includes a battery body 21 and a second power supply protection board 22. The battery body 21 is connected to the second power supply protection board 22, and the positive and negative output terminals of the second power supply protection board 22 are connected in parallel with the first power supply unit 10. By setting the second power supply protection board 22, the charging and discharging of the battery body 21 of the second power supply unit 20 can be controlled and protected, thereby further reducing its risk of spontaneous combustion.

[0044] Optionally, the second power supply protection board 22 is used to control the second power supply unit 20 to discharge only when the total voltage of the lithium battery is greater than or equal to the first voltage threshold; and / or, the second power supply protection board 22 is used to control the second power supply unit 20 to charge only when the total voltage of the lithium battery is less than or equal to the second voltage threshold, wherein the second voltage threshold is less than the first voltage threshold.

[0045] In this way, when the total voltage of the lithium battery in the second power supply unit 20 is higher than the maximum safe voltage (i.e., the first voltage threshold), the second power supply protection board 22 only allows the lithium battery to discharge and does not allow it to charge, thereby ensuring that it will not be damaged or spontaneously combusted due to overcharging.

[0046] When the total voltage of the lithium battery is lower than the minimum allowable voltage (i.e., the second voltage threshold), the second power supply protection board 22 only allows charging and not discharging, thereby avoiding over-discharge. The first voltage threshold is higher than the second voltage threshold.

[0047] The second power supply protection board 22 of the lithium battery can control its own charging and discharging, and control its own charging and discharging circuit as needed to decide whether to discharge and charge.

[0048] Of course, in other embodiments, the first power supply unit 10 may also be provided with a first power supply protection board, which is used to control the charging and discharging of the lead-acid battery, and there is no limitation on this.

[0049] In summary, the technical solution of this embodiment involves two types of batteries. Lead-acid batteries offer advantages such as low unit cost and high safety, while lithium batteries, although more expensive and riskier, have a smaller overall capacity. Therefore, while compensating for the low performance of lead-acid batteries, the introduction of cost and risk is minimal and controllable. Safety can be further enhanced by setting a second power supply protection board 22.

[0050] According to another aspect of this application, a two-wheeled electric vehicle is provided, which includes a drive motor 50 and a power supply device for the electric vehicle described above. The drive motor 50 is electrically connected to the power supply device, and the first power supply section 10 and the second power supply section 20 of the power supply device both output drive power to the drive motor 50.

[0051] The power supply device of this two-wheeled electric vehicle can use a hybrid power source of lead-acid batteries and lithium batteries, breaking the traditional mindset of either lead-acid batteries or lithium batteries. The hybrid mode achieves the effects of low cost, high safety and better performance, and all three points can be achieved at the same time, solving the problem that the traditional single battery solution cannot achieve these three points simultaneously.

[0052] When using a two-wheeled electric vehicle, if the lead-acid battery is insufficient to provide full power when the user accelerates rapidly, the lithium battery can be controlled to supplement the power. This is because an acceleration process, even from 0 to full speed, only lasts about 10 seconds. Assuming the lithium battery pack has a voltage of 80V and provides a current of 100A, the energy consumed by the lithium battery is only 22Wh, which is more than enough for the configured 300Wh lithium battery pack.

[0053] When the user decelerates, the motor controller performs kinetic energy recovery. Since the lead-acid battery's instantaneous charging capacity is insufficient, the lithium battery will step in to provide a large current absorption capacity and store the recovered energy.

[0054] This method solves the problem that when a user accelerates rapidly and the required current exceeds the maximum current that the lead-acid battery can provide, the acceleration rate must be reduced, otherwise the lead-acid battery will be damaged.

[0055] Optionally, to further enhance safety, the two-wheeled electric vehicle also includes a first and a second housing space that are isolated from each other. The first power supply unit 10 is located in the first housing space, and the second power supply unit 20 is located in the second housing space. This achieves isolation between the first power supply unit 10 and the second power supply unit 20, ensuring that a failure in the second power supply unit 20 is unlikely to affect the first power supply unit 10.

[0056] Of course, in other embodiments, the two-wheeled electric vehicle also includes a battery housing space, in which both the first power supply unit 10 and the second power supply unit 20 are disposed. Because the battery capacity of the second power supply unit 20 is very small, even if it spontaneously combusts, the destructive power is also very small, so it is acceptable to place the two together.

[0057] This utility model proposes a battery hybrid solution for a two-wheeled electric vehicle. It uses a large-capacity, inexpensive, and safe lead-acid battery in conjunction with a small-capacity, high-performance lithium battery as a hybrid power source to power the electric vehicle's power system. This combines the advantages of both and overcomes their respective disadvantages. The large-capacity lead-acid battery provides long-term range power because it is inexpensive and provides the majority of the vehicle's range, resulting in very low overall battery costs. The small-capacity, high-discharge-rate lithium battery provides instantaneous power for acceleration and instantaneous energy recovery for deceleration. Because of the small-capacity lithium battery, the overall battery cost is very low. Furthermore, in the event of spontaneous combustion or explosion, the low total capacity of the lithium battery limits the level of danger. Thus, a power supply solution that is inexpensive, safe, and high-performing is achieved.

[0058] The solution proposed in this application overcomes some cognitive deficiencies in the prior art (i.e., the discharge capacity of lead-acid batteries is stronger than that of lithium batteries), thereby improving the acceleration performance of two-wheeled electric vehicles with a new hybrid power supply method while ensuring safety.

[0059] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for specific applications, but such implementations should not be considered beyond the scope of the embodiments of this application.

[0060] The above embodiments are only used to illustrate the embodiments of this application, and are not intended to limit the embodiments of this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of this application. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of this application, and the patent protection scope of the embodiments of this application should be defined by the claims.

Claims

1. A power supply device for an electric vehicle, characterized in that, It includes a first power supply unit (10) and a second power supply unit (20). The first power supply unit (10) is a lead-acid battery, and the battery capacity of the first power supply unit (10) is greater than half of the total battery capacity of the power supply device. The second power supply unit (20) is connected in parallel with the first power supply unit (10), and the discharge rate of the second power supply unit (20) is greater than the discharge rate of the first power supply unit (10).

2. The power supply device for an electric vehicle according to claim 1, wherein The second power supply unit (20) is a lithium battery.

3. The power supply device for an electric vehicle according to claim 1 or 2, characterized by, The battery capacity of the second power supply unit (20) is less than or equal to one-third of the battery capacity of the first power supply unit (10), and the ratio of the discharge rate of the second power supply unit (20) to the discharge rate of the first power supply unit (10) is greater than or equal to 3:

1.

4. The power supply device for an electric vehicle according to claim 1, wherein The power supply device further includes an output bus (40), the first power supply unit (10) and the second power supply unit (20) are connected in parallel on the output bus (40), the output bus (40) is used to be directly or indirectly connected to the drive motor (50) of the electric vehicle, and all or part of the electrical energy recovered by the kinetic energy of the drive motor (50) is transmitted to the second power supply unit (20) through the output bus (40).

5. The power supply device for an electric vehicle according to claim 4, wherein The length of the output bus (40) between the first power supply unit (10) and the motor controller (30) of the drive motor (50) is the first conductor distance, and the length of the output bus (40) between the second power supply unit (20) and the motor controller (30) of the drive motor (50) is the second conductor distance. The first conductor distance is greater than or equal to the second conductor distance.

6. The power supply device for an electric vehicle according to claim 1 or 2, characterized by, The full voltage of the first power supply unit (10) is equal to the full voltage of the second power supply unit (20), or the difference between the full voltage of the first power supply unit (10) and the full voltage of the second power supply unit (20) is less than a set error value, wherein the set error value is less than or equal to 5V.

7. The power supply device for an electric vehicle according to claim 2, wherein The second power supply unit (20) includes a battery body (21) and a second power supply protection board (22). The battery body (21) is connected to the second power supply protection board (22), and the positive output terminal and negative output terminal of the second power supply protection board (22) are connected in parallel with the first power supply unit (10).

8. The power supply device for an electric vehicle according to claim 7, wherein The second power supply protection board (22) is used to control the second power supply unit (20) to discharge only when the total voltage of the lithium battery is greater than or equal to the first voltage threshold; and / or, the second power supply protection board (22) is used to control the second power supply unit (20) to charge only when the total voltage of the lithium battery is less than or equal to the second voltage threshold, wherein the second voltage threshold is less than the first voltage threshold.

9. A two-wheeled electric vehicle characterized by comprising: The electric vehicle includes a drive motor (50) and a power supply device for any one of claims 1-8, wherein the drive motor (50) is electrically connected to the power supply device, and both the first power supply unit (10) and the second power supply unit (20) of the power supply device output drive power to the drive motor (50).

10. The two-wheeled electric vehicle of claim 9, wherein, The two-wheeled electric vehicle also includes a first and a second housing space that are isolated from each other. The first power supply unit (10) is disposed in the first housing space and the second power supply unit (20) is disposed in the second housing space. Alternatively, the two-wheeled electric vehicle also includes a battery housing space, in which the first power supply unit (10) and the second power supply unit (20) are both disposed.

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