Method of estimating maximum output of battery for hybrid electric vehicle

• US 20060206276A1
• Filed: 03/06/2006
• Published: 09/14/2006
• Est. Priority Date: 03/04/2005
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Kim, Do Youn, Jung, Do Yang
• Granted Patent: US 7,518,375 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2240/662 Temperature
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: G01R 31/3832 without measurement of battery voltage
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/14 for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles

Abstract

Disclosed is a method of estimating a maximum output of a battery for a hybrid electric vehicle (HEV). The method comprises steps of: extracting maximum charge/discharge outputs of the battery depending on a plurality of charged states (SOC) of the battery under which the vehicle is able to be driven and calculating an interrelation between them; extracting maximum charge/discharge outputs of the battery at plural temperatures under which the vehicle is able to be driven, and calculating an interrelation between them; extracting degradations of outputs of the battery as a capacity of the battery is discharged during the traveling, and calculating an interrelation between them; and based on the interrelations obtained from each of the steps, estimating a maximum output (Power_max) of the battery through a following function. $\begin{array}{c}{\mathrm{Power}}_{\max }=F\left(\mathrm{SOC},\mathrm{temp},\mathrm{accumulated}\mathrm{discharge}\mathrm{Ah}\right)\\ =F\left(\mathrm{SOC},\mathrm{temp}\right)⨯F\left(\mathrm{accumlated}\mathrm{discharge}\mathrm{Ah}\right)\end{array}$

Claims

1. A method of estimating a maximum output of a battery for a hybrid electric vehicle comprising steps of:

extracting maximum charge/discharge outputs of the battery depending on a plurality of charged states (SOC) of the battery under which the vehicle is able to be driven and calculating an interrelation between them;

extracting maximum charge/discharge outputs of the battery at plural temperatures under which the vehicle is able to be driven, and calculating an interrelation between them;

extracting degradations of outputs of the battery as a capacity of the battery is discharged during the traveling, and calculating an interrelation between them; and

based on the interrelations obtained from each of the steps, estimating a maximum output (Power_max) of the battery through a following function.

$\begin{array}{c}{\mathrm{Power}}_{\max }=F<br><br>\left(\mathrm{SOC},\mathrm{temp},\mathrm{accumulated}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{discharge}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{Ah}\right)\\ =F<br><br>\left(\mathrm{SOC},\mathrm{temp}\right)⨯<br><br>F<br><br>\left(\mathrm{accumulated}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{discharge}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{Ah}\right)\end{array}$

2. The method according to claim 1, wherein the function, F (SOC, temp) is calculated by a following relational equation.

F(SOC, temp)=F(temp)₅×

SOC⁵+F(temp)₄×

SOC⁴+F(temp)₃×

SOC³+F(temp)₂×

SOC²+F(temp)₁×

SOC⁴+F(temp)₀

where F (temp)=D₂×

temp²+D₁×

temp¹+D₀(D₀˜

D₂;

constant)

3. The method according to claim 1, wherein the maximum output of the battery is compensated by a following relational equation showing a degradation of battery depending on the accumulated capacity of battery which is discharged during the traveling.

F(accumulated discharge Ah)=C₅k⁵+C₄k⁴+C₃k³+C₂k²+C₁k+C₀

Where each of C₅˜

C₀ is constant

k is a discharged capacity of the battery, is within an range of [0, 300000] and is inputted with a modified value within a range of [−

1, 1] when it is inputted as an input value into the function.

4. The method according to claim 3, wherein the degradation of the output depending on the discharged capacity of the battery is expressed by a following equation.

F(accumulated discharge Ah)=−

16.3986k⁵+15.0026k⁴+13.307k³−

8.38698k²−

7.96289k+82.3028

5. The method according to claim 4, further comprising a step of transmitting the estimated maximum output to a vehicle control device of the hybrid electric vehicle via a battery management system (BMS) to control the charge/discharge output of the battery.

6. The method according to claim 2, wherein the maximum output of the battery is compensated by a following relational equation showing a degradation of battery depending on the accumulated capacity of battery which is discharged during the traveling.

F(accumulated discharge Ah)=C₅k⁵+C₄k⁴+C₃k³+C₂k²+C₁k+C₀

Where each of C₅˜

C₀ is constant

k is a discharged capacity of the battery, is within an range of [0, 300000] and is inputted with a modified value within a range of [−

1, 1] when it is inputted as an input value into the function.

7. The method according to claim 6, wherein the degradation of the output depending on the discharged capacity of the battery is expressed by a following equation.

F(accumulated discharge Ah)=−

16.3986k⁵+15.0026k⁴+13.307k³−

8.38698k²−

7.96289k+82.3028

8. The method according to claim 7, further comprising a step of transmitting the estimated maximum output to a vehicle control device of the hybrid electric vehicle via a battery management system (BMS) to control the charge/discharge output of the battery.