Search

EP-4053572-B1 - METHOD AND APPARATUS FOR ESTIMATING STATE OF BATTERY

EP4053572B1EP 4053572 B1EP4053572 B1EP 4053572B1EP-4053572-B1

Inventors

  • KIM, JINHO
  • SONG, TAE WON
  • SUNG, YOUNG HUN

Dates

Publication Date
20260506
Application Date
20220302

Claims (15)

  1. A processor-implemented method of estimating a state of a battery, the method comprising: obtaining (1610) a measured voltage of a battery (110) from a sensor connected to the battery (110); obtaining (1620) an estimated voltage of the battery from an electrochemical model stored in a memory; the method is characterised by estimating (1630) an aging variation of the battery (110) based on the measured voltage and the estimated voltage; and updating (1640) an aging parameter of the electrochemical model using the aging variation.
  2. The method of claim 1, wherein the estimating (1630) of the aging variation comprises estimating the aging variation based on a response characteristic difference between the estimated voltage of the battery and the measured voltage of the battery.
  3. The method of claim 2, wherein the estimating of the aging variation comprises one of: determining a resistance increase based on a variation in the estimated voltage, a variation in the measured voltage, and a current variation of the battery, and determining a variation in an anodic solid electrolyte interphase, SEI, resistance to be the aging variation based on the resistance increase; estimating the aging variation in response to a corrector with respect to the electrochemical model being controlled to be in an OFF state; and determining a ratio between a response characteristic of the estimated voltage and a response characteristic of the measured voltage according to discharging of the battery to be the aging variation.
  4. The method of claim 3, wherein the ratio between the response characteristic of the estimated voltage and the response characteristic of the measured voltage comprises one of a ratio between a slope determined from estimated voltages and a slope determined from measured voltages at two points within a use interval of the battery; and a ratio between an area determined from estimated voltages and an area determined from measured voltages between two points within a use interval of the battery, and wherein the two points within the use interval of the battery correspond to a start point and an end point of an OFF-state interval of a corrector with respect to the electrochemical model, or belong to an interval in which a current change of the battery is less than or equal to a first threshold within the OFF-state interval.
  5. The method of one of claims 1 to 4, further comprising: controlling an operation state of a corrector (1020) with respect to the electrochemical model (1030) using state information of the battery (1010) estimated by the electrochemical model (1030).
  6. The method of claim 5, further comprising one of: controlling the corrector (1020) to be in an OFF state in response to any one of the state information of the battery (1010), an ion concentration of the battery, and a capacity for active material of the battery being greater than a second threshold or falling within a first range; controlling the corrector (1020) to be in the OFF state, if any one of the state information of the battery, an ion concentration of the battery, and a capacity for active material of the battery corresponds to an interval in which a change in an anode open circuit potential, OCP, of the battery is less than or equal to a third threshold and a change in a cathode OCP of the battery is greater than or equal to a fourth threshold; controlling the corrector (1020) to be in the ON state in response to any one of the state information of the battery, an ion concentration of the battery, and a capacity for active material of the battery being less than a fifth threshold or falling within a second range; and controlling the corrector (1020) to be in the ON state, if any one of the state information of the battery, an ion concentration of the battery, and a capacity for active material of the battery corresponds to an interval in which a change in an anode OCP of the battery is greater than or equal to a sixth threshold, wherein the estimating of the aging variation comprises determining a degree in which the state information of the battery is corrected by the corrector to be the aging variation, in response to the corrector being controlled to be in an ON state.
  7. The method of one of claims 1 to 6, further comprising: storing the aging variation in the memory; and updating the aging parameter using one or more aging variations stored in the memory, in response to an update condition for the aging parameter being reached, and wherein whether the update condition has been reached is determined based on one or more of a number of cycles of the battery, a cumulative use capacity of the battery, a cumulative use time of the battery, and a number of aging variations stored in the memory.
  8. The method of one of claims 1 to 7, wherein the aging parameter comprises one or more of an anodic solid electrolyte interphase, SEI, resistance, a capacity for cathode active material, and an electrode balance shift of the battery.
  9. The method of one of claims 1 to 8, further comprising: estimating state information of the battery using the electrochemical model to which the updated aging parameter is applied.
  10. A non-transitory computer-readable storage medium storing instructions that, when executed by a processor (1520) of an apparatus for estimating a state of a battery comprising a memory (1510) configured to store an electrochemical model and a sensor (1530) configured to measure a voltage of the battery, cause the processor (1520) to: estimate (1630) an aging variation of the battery based on a measured voltage of the battery and an estimated voltage obtained from the electrochemical model, and update (1640) an aging parameter of the electrochemical model using the aging variation.
  11. A mobile device, comprising: a display (1810); a battery (1820) configured to supply power to the display (1810); and a battery state estimation apparatus comprising: a memory (1830) configured to store an electrochemical model for the battery (1820), a sensor configured to measure a voltage of the battery (1820), and a processor (1840) configured to estimate a state of the battery (1820) according to one of method claims 1 to 9.
  12. The mobile device of claim 11, wherein a diagonal length of the display (1810) is one of 10 centimeters, cm, to 70 cm, or 50 cm or less than 50 cm.
  13. The mobile device of claim 11 or 12, wherein a unit cell capacity of the battery (1820) is 10 ampere hours, Ah, or less, or wherein the processor (1840) is a micro controller unit, MCU, or wherein the memory (1830) includes either a volatile memory having a capacity of 2 to 8 kilobytes per unit cell, or a non-volatile memory having a capacity of 20 to 100 kilobytes per unit cell.
  14. The mobile device of one of claims 11 to 13, further comprising one of: a power management integrated circuit, PMIC, wherein the memory (1830) and the processor (1840) are either included in the PMIC or are not included in the PMIC; a camera (1850) configured to capture a user looking at the display (1810); a cover, wherein the battery (1820), the memory (1830), and the processor (1840) are disposed between the cover and the display (1810); and the display (1810) being a touchscreen display configured to detect a touch gesture input from a user.
  15. The mobile device of one of claims 11 to 14, further comprising: a communicator (1860) configured to communicate with an external device, wherein the communicator (1860) is further configured to transmit data received from the external device to the processor (1840), and to transmit data processed by the processor (1840) to the external device, or a speaker (1870) configured to output a sound according to an operation of the mobile device.

Description

BACKGROUND 1. Field The following description relates to a method and apparatus for estimating a state of a battery. 2. Description of Related Art For battery management, states of batteries may be estimated using various methods. For example, the states of batteries may be estimated by integrating currents of the batteries or by using a battery model (for example, an electric circuit model). The more often batteries are exposed to a management environment that accelerates aging (e.g., fast charging, fast discharging, low-temperature, or high-temperature environment), the higher the need for predicting state information of batteries reflecting aged states. US 2017/0205469 A1 refers to an apparatus and method for estimating a state of a battery. The battery state estimation apparatus includes a state of health, SOH, estimator configured to estimate SOH of a battery based on degradation of the battery and the data acquired from the battery, and a state of charge, SOC, estimator configured to estimate the SOC of the battery based on the SOH of the battery. SUMMARY This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The invention is claimed in the independent claims. Preferred embodiments are specified in the dependent claims. In one general aspect, a processor-implemented method of estimating a state of a battery includes obtaining a measured voltage of a battery from a sensor connected to the battery, obtaining an estimated voltage of the battery from an electrochemical model stored in a memory, estimating an aging variation of the battery based on the measured voltage and the estimated voltage, and updating an aging parameter of the electrochemical model using the aging variation. The estimating of the aging variation may include estimating the aging variation based on a response characteristic difference between the estimated voltage of the battery and the measured voltage of the battery. The estimating of the aging variation may include determining a resistance increase based on a variation in the estimated voltage, a variation in the measured voltage, and a current variation of the battery, and determining a variation in the anodic solid electrolyte interphase (SEI) resistance to be the aging variation based on the resistance increase. The estimating of the aging variation may include determining a ratio between a response characteristic of the estimated voltage and a response characteristic of the measured voltage according to discharging of the battery to be the aging variation. The ratio between the response characteristics of the estimated voltage and the response characteristic of the measured voltage may include one of a ratio between a slope determined from estimated voltages and a slope determined from measured voltages at two points within a use interval of the battery, and a ratio between an area determined from estimated voltages and an area determined from measured voltages between two points within a use interval of the battery. The two points within the use interval of the battery may correspond to a start point and an end point of an OFF-state interval of a corrector with respect to the electrochemical model, or belong to an interval in which a current change of the battery is less than or equal to a first threshold within the OFF-state interval. The estimating of the aging variation may include estimating the aging variation in response to a corrector with respect to the electrochemical model being controlled to be in an OFF state. The method may further include controlling an operation state of a corrector with respect to the electrochemical model using state information of the battery estimated by the electrochemical model. The method may include controlling the corrector to be in an OFF state in response to any one of the state information of the battery, an ion concentration of the battery, and a capacity for active material of the battery being greater than a second threshold or falling within a first range. The method may include controlling the corrector to be in the OFF state, if any one of the state information of the battery, an ion concentration of the battery, and a capacity for active material of the battery corresponds to an interval in which a change in an anode open circuit potential (OCP) of the battery is less than or equal to a third threshold and a change in a cathode OCP of the battery is greater than or equal to a fourth threshold. The estimating of the aging variation may include determining a degree in which the state information of the battery is corrected by the corrector to be the aging variation, in response to the corrector being controlled to be in an ON state. The meth