Range extending apparatus for electric vehicle and control method thereof

• US 10,377,262 B2
• Filed: 12/06/2016
• Issued: 08/13/2019
• Est. Priority Date: 12/06/2016
• Status: Active Grant

• Current Assignee: National Chung-Shan Institute of Science and Technology
• Original Assignee: National Chung-Shan Institute of Science and Technology
• Inventors: Hsiao, Wei-Min, Jen, Kuo-Kuang, Lin, Jeng-Chyan, Hsien, Hsun-Ming, Fang, Fu-Min
• Primary Examiner(s): Sun, Pinping
• Application Number:
  US15/370,889
• Publication Number:
  US 20180154794A1
• Time in Patent Office: 980 Days
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 50/60 using power supplied by batteries in combination with fuel cells B60L50/75
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: B60L 7/16 for vehicles comprising converters between the power source and the motor
• CPC Class Codes: B60L 8/003 Converting light into electric energy, e.g. by using photo-voltaic systems
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/92 Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles

Abstract

Electric vehicle range extending apparatus includes a step-down voltage provision unit, cell voltage sensing unit, cell switching unit, and control unit. The step-down voltage provision unit has an input port to be coupled to the main battery pack or an auxiliary battery pack, and an output port to output a power balancing signal. The cell voltage sensing unit is for being coupled to the battery cells and sensing individual voltages of the battery cells. The cell switching unit, including a plurality of switches, is coupled to the battery cells respectively, and coupled to the output port. The control unit, coupled to the cell voltage sensing unit, step-down voltage provision unit, and cell switching unit, is for controlling the cell switching unit based on the individual voltages of the battery cells so as to apply the power balancing signal to at least one of the battery cells selectively.

Claims

1. An electric vehicle range extending apparatus, for use in an electric vehicle with a main battery pack including a plurality of battery cells, the apparatus comprising:

a step-down voltage provision unit, having;

an input port to be coupled to the main battery pack or an auxiliary battery pack, and an output port to output a power balancing signal;

a cell voltage sensing circuit, for being coupled to the plurality of battery cells and sensing individual voltages of the plurality of battery cells;

a cell switching circuit, including a plurality of switches, coupled to the plurality of battery cells respectively, and coupled to the output port; and

a control circuit, coupled to the cell voltage sensing circuit, the step-down voltage provision unit, and the cell switching circuit, for controlling the cell switching circuit based on the individual voltages of the plurality of battery cells so as to apply the power balancing signal to at least one of the plurality of battery cells selectively;

wherein the control circuit determines, among the plurality of battery cells, a first battery cell with a highest voltage and a second battery cell with a lowest voltage, based on the individual voltages of the plurality of battery cells;

wherein the control circuit determines whether a voltage difference between the first battery cell and the second battery cell is greater than a balance setting value;

wherein the control circuit determines whether a voltage of the second battery cell lies between a balance starting value and a voltage setting value if the voltage difference between the first battery cell and the second battery cell is greater than the balance setting value;

wherein the control circuit controls the cell switching circuit so as to apply the power balancing signal selectively to the second battery cell if the voltage of the second battery cell lies between the balance starting value and the voltage setting value; and

wherein control circuit stops to apply the power balancing signal to the second battery cell if the control circuit determines a voltage difference between the second battery cell and a battery cell having a lowest voltage among the plurality of battery cells except the second battery cell is greater than a balance cut-off value.

2. The electric vehicle range extending apparatus as claimed in claim 1, wherein the control circuit is for determining the second battery cell with the lowest voltage among the plurality of battery cells, based on the individual voltages of the plurality of battery cells, and accordingly controlling the cell switching circuit to apply the power balancing signal selectively to the second battery cell with the lowest voltage.

3. The electric vehicle range extending apparatus as claimed in claim 1, wherein the control circuit enables the input port to be coupled to the main battery pack or the auxiliary battery pack selectively based on whether the auxiliary battery pack has sufficient electricity, so that the step-down voltage provision unit outputs the power balancing signal from the output port.

4. The electric vehicle range extending apparatus as claimed in claim 1, wherein the auxiliary battery pack is coupled to a renewable electricity generation system and obtains energy therefrom.

5. The electric vehicle range extending apparatus as claimed in claim 4, wherein the renewable electricity generation system is a solar electricity generation system.

6. The electric vehicle range extending apparatus as claimed in claim 1, wherein the auxiliary battery pack is coupled to a regenerative braking system and obtains energy therefrom.

7. The electric vehicle range extending apparatus as claimed in claim 6, wherein the regenerative braking system is an in-wheel generator of the electric vehicle.

8. An electric vehicle range extending method, comprising:

a) providing an electric vehicle range extending apparatus in an electric vehicle, wherein the electric vehicle has a main battery pack including a plurality of battery cells, the apparatus comprising a cell voltage sensing circuit, a step-down voltage provision unit, a cell switching circuit, and a control circuit, the step-down voltage provision unit, coupled to the main battery pack or an auxiliary battery pack, is for outputting a power balancing signal;

b) sensing individual voltages of the plurality of battery cells by using the cell voltage sensing circuit; and

c) controlling the cell switching circuit, by the control circuit based on the individual voltages of the plurality of battery cells, to apply the power balancing signal to at least one of the plurality of battery cells selectively, comprising;

determining, among the plurality of battery cells, a first battery cell with a highest voltage and a second battery cell with a lowest voltage, based on the individual voltages of the plurality of battery cells;

determining whether a voltage difference between the first battery cell and the second battery cell is greater than a balance setting value;

determining whether a voltage of the second battery cell lies between a balance starting value and a voltage setting value if the voltage difference between the first battery cell and the second battery cell is greater than the balance setting value; and

controlling the cell switching circuit to apply the power balancing signal selectively to the second battery cell if the voltage of the second battery cell lies between the balance starting value and the voltage setting value;

and d) stopping to apply the power balancing signal to the second battery cell if a voltage difference between the second battery cell and a battery cell having a lowest voltage among plurality of battery cells except the second battery cell is greater than a balance cut-off value.

9. The electric vehicle range extending method as claimed in claim 8, further comprises:

determining, by the control circuit, the second battery cell with the lowest voltage among the plurality of battery cells, based on the individual voltages of the plurality of battery cells, and accordingly controlling the cell switching circuit so as to apply the power balancing signal selectively to the second battery cell with the lowest voltage.

10. The electric vehicle range extending method as claimed in claim 8, further comprising:

enabling the step-down voltage provision unit to be coupled to the main battery pack or the auxiliary battery pack selectively, by using the control circuit based on whether the auxiliary battery pack has sufficient electricity, so that the step-down voltage provision unit outputs the power balancing signal from the output port.

11. The electric vehicle range extending method as claimed in claim 10, further comprising:

if the auxiliary battery pack has sufficient electricity, enabling the step-down voltage provision unit to be coupled to the auxiliary battery pack, so that the step-down voltage provision unit outputs the power balancing signal;

if the auxiliary battery pack has not sufficient electricity, enabling the step-down voltage provision unit to be coupled to the main battery pack, so that the step-down voltage provision unit outputs the power balancing signal.