Available charging/discharging current calculation method and power supply device

• US 9,071,072 B2
• Filed: 11/09/2010
• Issued: 06/30/2015
• Est. Priority Date: 11/11/2009
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Tamezane, Shigeto
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): BOATENG, ALEXIS ASIEDUA
• Application Number:
  US12/942,254
• Publication Number:
  US 20110109273A1
• Time in Patent Office: 1,694 Days
• Field of Search: 320/132, 320/133, 320/127, 320/128, 320/144, 320/153, 320/164, 320/161
• US Class Current: 1/1
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 50/569 Constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals battery terminal connectors with integrated measuring arrangements G01R31/364
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• 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 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles

Abstract

A method includes steps of dividing resistance R into a physical and chemical resistances R_o and R_p, obtaining corrected open-circuit voltages V_o corresponding to setting currents I_a to I_x, acquiring predicted reaching voltages V_a to V_x corresponding to the setting currents I_a to I_x, and creating a current-voltage curve. The corrected open-circuit voltages V_o are obtained to predict available maximum currents I_—target in a particular time t₂. The predicted reaching voltages V_a to V_x are acquired based on corrected physical and chemical resistances R_o and R_p, and the corrected open-circuit voltages V_o. The current-voltage curve is creased based on the setting currents I_a to I_x and the predicted reaching voltages V_a to V_x to acquire upper and lower limit voltages V_max and V_min, and upper and lower limit currents I_max and I_min at a temperature whereby assigning these limit currents to available maximum currents I_—target in charging and discharging operations, respectively.

Claims

1. An available charging/discharging current calculation method that estimates available maximum current values in charging/discharging operations of batteries based on at least one of battery current, voltage and temperature, the method comprising the steps of:

calculating a resistance value based on an average current value and an average voltage obtained in a predetermined time period;

dividing the calculated resistance value into a physical resistance component and a chemical resistance component;

correcting the chemical resistance component based on the pulse discharging or charging operation time from the past to the present;

acquiring voltage variation values in the history of the past charging/discharging operations;

correcting the physical resistance component based on a detected battery temperature and a detected battery remaining capacity;

estimating battery open-circuit voltages based on the physical and chemical resistance components, and a current, a voltage and the voltage variation values;

obtaining corrected battery open-circuit voltages corresponding to a plurality of setting currents in order to predict the available maximum current values in a particular time;

acquiring predicted reaching voltages corresponding to the plurality of setting currents based on said corrected physical resistance component, said corrected chemical resistance component and said corrected battery open-circuit voltages; and

creating a battery current-voltage curve based on said setting currents and said predicted reaching voltages to acquire upper and lower limit voltages and upper and lower limit currents at a temperature whereby assigning the upper and lower limit currents to the available maximum current values in charging operation and discharging operation, respectively.

2. The available charging/discharging current calculation method according to claim 1 further comprising, in order to predict the available maximum current values in the particular time, correcting the chemical resistance component based on the prediction time or the sum of the pulse time until the present and the prediction time, and correcting the physical resistance component based on the battery remaining capacities corresponding to a plurality of setting currents and the battery temperature.

3. The available charging/discharging current calculation method according to claim 1, wherein said resistance value is a weighted average value of a resistance value acquired in the past and a resistance value acquired at the present.

4. The available charging/discharging current calculation method according to claim 1, wherein said voltage variation is the sum of values obtained by products each of which is obtained by multiplying each of chemical resistances that are subjected to the time-based correction in a predetermined times of pulse charging/discharging operations in the past, the current and a coefficient depending on time from the end of each of the pulse charging/discharging operations.

5. The available charging/discharging current calculation method according to claim 1, wherein said lower limit voltage is set at a voltage until which the battery current-voltage curve can continuously have linearity.

6. The available charging/discharging current calculation method according to claim 1, wherein if said lower limit voltage is set at a low voltage until which the battery current-voltage curve cannot continuously have linearity, said predicted reaching voltages are corrected.

7. The available charging/discharging current calculation method according to claim 6, wherein, in order to correct said predicted reaching voltages, said predicted reaching voltages are corrected based on the difference or ratio between said predicted reaching voltages and said lower limit voltage until which the battery current-voltage curve can continuously have linearity.

8. The available charging/discharging current calculation method according to claim 7, wherein the voltage is corrected, or the chemical resistance component or the physical resistance component are corrected based on said difference or ratio between said predicted reaching voltages and said lower limit voltage, and the predicted reaching voltages are acquired again.

9. The available charging/discharging current calculation method according to claim 1, wherein when a detected voltage is not higher than a setting voltage, the chemical resistance component is corrected.

10. The available charging/discharging current calculation method according to claim 1, wherein said batteries are lithium-ion rechargeable batteries.

11. The available charging/discharging current calculation method according to claim 1 further comprising transmitting the estimated available charging/discharging current values to a connected device that has an information processing system.