WO2016175455A1

WO2016175455A1 - Dual battery package

Info

Publication number: WO2016175455A1
Application number: PCT/KR2016/003011
Authority: WO
Inventors: 송동하; 노정욱
Original assignee: 스마클(주)
Priority date: 2015-04-29
Filing date: 2016-03-24
Publication date: 2016-11-03
Also published as: KR20160128805A; KR101686864B1

Abstract

The present invention relates to a lightweight battery package for an electric bicycle. A dual battery package comprises: a battery; a boost converter; and a capacitor of which one end is connected to the boost converter and a positive electrode of the battery at a first node, and of which the other end is connected to the boost converter at a second node, wherein an electric current is supplied to an external load through the second node. Such an implemented dual battery package can enhance reliability and reduce the weight, volume and cost of a battery, compared to existing products.

Description

Dual battery package

The present invention relates to a lightweight battery package for an electric bicycle.

The electric bicycle has a battery, a motor driven inverter and a motor. An electric bicycle can use the power of the occupant to pedal, but it also uses the power of the motor.

Existing bicycles with step-down inverters must be set at a higher battery voltage (eg 36V) than the motor's rated voltage of 24V. As a battery for an electric bicycle, a lithium-based secondary battery is mainly used. In order to obtain such a voltage, battery cells are connected in series. Connecting battery cells in series has been a factor in lowering the overall reliability of the battery. On the other hand, the discharge current of the battery must be large so that the maximum current can be instantaneously supplied to the motor. To this end, several batteries may be connected in parallel.

These factors reduce the reliability of the battery, increase the weight and volume of the battery and further increase the cost of the electric bicycle.

Figure 1 shows the drive of a conventional electric bicycle using a battery power of 36V / 10A.

The battery 10 is implemented by connecting three battery cells of 12V / 10A in series so as to supply a voltage of 36V and a current of 10A. The battery 10 is supplied to the inverter circuit 20 and supplies current. The inverter circuit 20 drives the motor 30.

Referring to FIG. 2, the current electric bicycle is very slow immediately after starting (starting), but the current supplied to the motor increases rapidly. Then, when the speed reaches maximum (in normal driving), the current supplied to the motor is reduced again. The battery must be able to supply this maximum current. When the maximum current supplied from the battery is small, the acceleration of the electric bicycle is reduced. Therefore, use a battery with sufficient current supply to get the proper acceleration when starting the electric bike.

3 is a conceptual diagram showing the configuration of an inverter circuit.

The inverter circuit 20 receives current from the battery 10 and supplies it to the motor 30. Typically, the inverter circuit 20 includes a plurality of inverters 21 (for example, six).

The inverter 21 supplies a current to the motor 30 according to the signal of the PWM signal generator 22. The inverter 21 supplies a small current to the motor 30 when the duty ratio of the signal generated by the PWM signal generator 22 is small and a large current when the duty ratio is large.

The process of generating a PWM signal is as follows.

When the first comparator 26 outputs a value obtained by comparing the target angular velocity signal with the current angular velocity of the motor 30, the speed controller 25 multiplies the value by a certain constant to generate the target current signal.

When the second comparator 24 compares the current supplied by the inverter 21 to the motor 30 with the target current, the current controller 23 multiplies the value by another constant value to generate the target voltage signal.

The PWM signal generator 22 generates a PWM signal having a duty ratio according to the target voltage signal, and the inverter 21 supplies current to the motor by using the PWM signal generator 22.

This prior art connects many battery cells in series and in parallel for high battery voltages and large currents. This leads to battery reliability, weight increase, volume increase and cost increase.

Patent No. 10-1065309 discloses a technique for solving such a problem. Specifically, the capacitor is used to charge the current supplied by the battery in normal times, and when the maximum current is required, the capacitor current is supplied to the motor together with the battery current. This reduces the number of parallel connections of the batteries and reduces weight, volume and cost. Nevertheless, this technology still requires the use of high voltage capacitors, and the problem of reduced reliability due to the series connection of multiple batteries remains.

Meanwhile, when the battery of the conventional electric bicycle is discharged, it is replaced with a battery that is already charged or charged using a separate external charger. However, when using an electric bicycle, there is an inconvenience of having to carry a charged replacement battery or an external charger separately.

Accordingly, the present invention aims to solve the above-mentioned problems of the prior art.

One object of the present invention is to solve the problem of using a high voltage battery by using a capacitor, and to reduce the weight and cost of the battery.

Another object of the present invention is to integrate the charger or inverter circuit with the battery in the battery package to increase the reliability of the battery package, reduce the cost and ease of use.

The characteristic structure of this invention for achieving the objective of this invention mentioned above, and realizing the characteristic effect of this invention mentioned later is as follows.

According to one aspect of the present invention, a dual battery package includes a battery, a boost converter, and a capacitor, one end of which is connected to the anode and the boost converter of the battery at a first node and the other end of which is connected to the boost converter at a second node; The current is supplied to an external load through the second node.

According to another aspect of the invention, a dual battery package includes a charger in addition to a battery, a boost converter and a capacitor. In this case, the secondary coil of the transformer included in the charger may serve as an inductor of the boost converter.

According to another aspect of the invention, a dual battery package includes an inverter circuit in addition to a battery, a boost converter and a capacitor.

According to at least some embodiments of the present invention, a dual battery package can use a low voltage battery because it uses a battery and a capacitor together, which enables increased battery package reliability, reduced weight and volume, and reduced cost. .

According to at least some embodiments of the present invention, the dual battery package incorporates a charger, greatly increasing user convenience. In addition, cost savings can be achieved by organically integrating some components of the charger with those of existing battery packages.

According to at least some embodiments of the present invention, a dual battery package incorporates inverter circuits, which can be expected to increase reliability when compared to separate designs.

1 is a conceptual diagram showing a driving unit of a conventional electric bicycle.

2 is a graph showing the amount of current supplied to the motor of the electric bicycle.

3 is a conceptual diagram showing the configuration of an inverter circuit.

4 illustrates a dual battery package according to an embodiment of the present invention.

5 is a diagram schematically illustrating a configuration of a boost converter.

6 illustrates a dual battery package according to another embodiment of the present invention.

7 illustrates a dual battery package according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The following detailed description of the invention refers to the accompanying drawings that show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different but need not be mutually exclusive. For example, certain shapes, structures, and characteristics described herein may be embodied in other embodiments without departing from the spirit and scope of the invention with respect to one embodiment. In addition, it is to be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled. Like reference numerals in the drawings refer to the same or similar functions throughout the several aspects.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention.

The dual battery package 1 includes a battery 100, a capacitor 200, and a boost converter 300.

The dual battery package 1 supplies a current according to the user's control to the inverter circuit 400, in which both the capacitor 200 and the battery 100 are inverters when the electric bicycle is started or the output of the motor needs to be maximized. When the current is supplied to the circuit 400 and the motor does not have to maximize the output (for example, during normal driving), only the battery 100 supplies current.

The battery 100 may connect two 12V / 10A battery cells in parallel. The positive electrode of the battery 100 is connected to node 1 and the negative electrode of the battery 100 is connected to the ground. The battery 100 includes a boost converter 300 to supply current or voltage to various control circuits (not shown).

The voltage of 12V supplied through node 1 is boosted to 36V by boost converter 300. Therefore, the capacitor 200 connected between the node 1 and the node 2 is subjected to a voltage of 24V.

The inverter circuit 400 receives a current from the dual battery package 1 and supplies a current proportional thereto to the motor 500. The inverter circuit 400 may include a plurality of inverters. You can also use a proven inverter circuit.

The inverter circuit 400 may be implemented as a step-down six-switch DC / AC inverter (which can be implemented with six Power MOSFETs) suitable for a brush-less direct current (BLDC) motor or a permanent-magnetic synchronous motor (PMSM). It can be implemented to include microprocessor and inverter control logic for on and off control of the MOSFET. When implementing the inverter circuit 400 in the present embodiment, a circuit generally used conventionally is employed.

Although the inverter circuit 400 may be implemented separately without being included in the dual battery package as in the embodiment of FIG. 4, the inverter circuit 400 may be implemented to be included in the dual battery package. When implemented in a dual battery package, the price of the dual battery package increases, but it is possible to avoid the deterioration of reliability due to the integration of the two separately. On the other hand, the price increase of the dual battery package can be offset by reducing the cost of implementing separate inverter circuits. The following other embodiments are described based on the fact that the inverter circuit is not implemented in the dual battery package, and the description of the integrated version is omitted.

The motor 500 receives a current from the inverter circuit 400 and rotates. Either a BLDC motor or a PMSM motor may be adopted. DC motors can be used to implement low-cost electric bicycles, in which case modifications to the inverter circuits are required.

Hereinafter, the operation of the dual battery package will be described.

When the electric bicycle is started, part of the required current is supplied from the battery 100 to the inverter circuit 400 via the boost converter 300 via node 2. By appropriate control of the boost converter, it is possible to limit the maximum value of the current supplied from the battery 100, thereby reducing the capacity of the battery 100, that is, the number of parallel connected cells. The insufficient current required for the inverter circuit 400 at startup is supplied from the capacitor 200 via node 2.

There is no current supplied from the capacitor 200 to the inverter circuit 400 when the electric bicycle is started and is operating normally. The battery 100 supplies all necessary inverter 400 circuit current through the boost converter 300. do. That is, since the capacitor 200 only supplies power for a short time during startup, it can be implemented with a small capacity. This results in a lighter and lower cost battery package.

When the electric bicycle is braked, the reverse current generated by the motor 500 is supplied to the capacitor 200 through the node 2 via the inverter 400 to partially charge the discharged capacitor 200 at startup. When the electric bicycle is in a full stop (rest), the battery 100 is fully charged by the discharged capacitor 200 at start-up via the boost converter 300.

The boost converter used in the present invention may adopt a power circuit topology generally used.

5 shows an example of the configuration of the boost converter. The boost converter 300 includes an inductor Lb 320, a switching unit 330, and a switching unit 310 between the node 1 and the node 2 and the ground node, and the switching unit 330 in the converter control circuit 340. Repeat the conduction interruption according to the generated switch conduction / interruption signal

The switching unit 310 mainly uses a diode D6, and in some cases, SW1 may be added. However, SW1 should be turned on / off so that SW1 conduction only occurs when SW2 is interrupted and SW1 interruption occurs when SW2 is conducted. The signal generated from the control circuit 340 is usually a signal of several tens of KHz or more, and when the conduction signal is generated, the switching unit 330 is turned on and the switching unit 310 is cut off. At this time, current flows through the path of the battery 100-inductor Lb-SW2 and energy is stored in the inductor.

When the blocking signal is generated, the switching unit 330 is cut off, and the energy stored in the inductor through the path of the battery 100-inductor-SW1 is added to the battery 100 and transferred to the inverter circuit 400. Therefore, the voltage between the node N2 and the ground node is boosted to be greater than the voltage of the battery 100 and is applied to the inverter circuit 400.

The conduction / blocking operation of the switch 330 is repeated in a period of Ts. When the switch conduction time is Ton, the ratio D may be defined as Ton / Ts.

If a large number of inverter currents are required at the start of the electric bicycle, the operation rate D is increased. The conduction time of the switch 330 is long, and the energy stored in the inductor is increased, thereby providing the necessary power at the moment of startup. However, the size of the fertilization rate D is limited and operated so that more than the allowable current of the battery 100 is supplied. The power which is insufficient at the start-up is supplied by the capacitor 200 as described above. Under normal / operational conditions, the application rate D is lowered. During braking or at complete rest, the rate D adjustment operation is performed such that the voltage between node 2 and the ground node is less than the inverter 400 allowable voltage. This helps the life of the battery 100.

The dual battery package 2, like the dual battery package 1 of FIG. 4, includes not only the dual battery device 600, which is a circuit including a battery, a boost converter, and a capacitor, but also a charger 700. The charger 700 is provided with a transformer 710 to lower the AC voltage of 220V to reduce damage that may occur to the battery during the charging process, as well as electrical insulation to ensure the safety of the user electric shock accidents. .

The inverter circuit 400 is not included in the dual battery package 1 but may be implemented to be included.

The dual battery package 2 of FIG. 6 merely reduces the inconvenience of having the user carry the charger separately by including the charger 700 in the dual battery package. However, the dual battery package 3 according to the present embodiment is conventional. The inductor included in the boost converter is used as the secondary coil of the transformer 910 included in the charger 900. This can reduce parts, reduce cost and weight.

Although the present invention has been described by specific embodiments such as specific components and the like, but the embodiments and the drawings are provided to assist in a more general understanding of the present invention, the present invention is not limited to the above embodiments. For those skilled in the art, various modifications and variations can be made from such descriptions.

Therefore, the spirit of the present invention should not be limited to the embodiments described above, and all of the equivalents or equivalents of the claims, as well as the claims below, are included in the scope of the spirit of the present invention. I will say.

Claims

A battery, a boost converter, and a capacitor having one end connected to a positive electrode of the battery and the boost converter at a first node and the other end connected to the boost converter at a second node,

Dual battery package for supplying current to an external load through a second node.
The method of claim 1, wherein the boost converter

An inductor coupled between the first node and a third node, the inductor temporarily storing energy for boosting;

A first switching unit connected between the second node and the third node;

A second switching unit connected between the third node and a negative electrode of the battery; And

And a converter control circuit for conducting a second switching unit when the first switching unit is blocked, and for blocking the second switching unit when the first switching unit is conductive.
The method of claim 2, wherein the converter control circuit

The output of the boost converter is controlled as a ratio (Ton / Ts), which is a time (Ton) at which the second switching unit is turned on and a time (Ts) at which the second switching unit is interrupted. A dual battery package, wherein the voltage is maintained below the permissible voltage.
A battery, a boost converter, a capacitor of one end connected to the positive electrode and the boost converter at the first node and the other end connected to the boost converter at a second node, and a battery charger,

The battery charger includes a transformer, one end of the secondary coil of the transformer is connected to the positive electrode of the battery and the other end is connected to the boost converter to serve as an inductor to temporarily store energy in a boosting operation. Dual battery package.
The method of claim 4, wherein the boost converter

An inductor coupled between the first node and a third node, temporarily storing energy for boosting, and being a secondary coil of the transformer;

A first switching unit connected between the second node and the third node;

A second switching unit connected between the third node and a negative electrode of the battery; And

And a converter control circuit for conducting a second switching unit when the first switching unit is blocked, and for blocking the second switching unit when the first switching unit is conductive.