Search

EP-4741848-A1 - BATTERY SYSTEM AND BATTERY PACK DIAGNOSIS METHOD BY SUPPLEMENTING CELL VOLTAGE AND CELL TEMPERATURE DATA

EP4741848A1EP 4741848 A1EP4741848 A1EP 4741848A1EP-4741848-A1

Abstract

The present disclosure relates to a battery system and a battery pack diagnosis method by supplementing a cell voltage and cell temperature data. The battery system may include a battery pack that includes a plurality of battery cells, a cell monitoring controller (CMC) that is configured to monitor a plurality of first cell voltages and a plurality of first cell temperatures of the plurality of battery cells, and a battery management system (BMS) that is configured to determine a wireless communication status with the CMC, diagnose the battery pack based on the plurality of first cell voltages and the plurality of first cell temperatures received from the CMC according to the wireless communication status with the CMC, and diagnose the battery pack by estimating a plurality of second cell voltages and a plurality of second cell temperatures of the plurality of battery cells.

Inventors

  • KI, JEONG SEOK
  • JUNG, Yoonchul
  • PARK, WON SEOK

Assignees

  • LG Energy Solution, Ltd.

Dates

Publication Date
20260513
Application Date
20240627

Claims (12)

  1. A battery system, comprising: a battery pack that includes a plurality of battery cells; a cell monitoring controller (CMC) that is configured to monitor a plurality of first cell voltages and a plurality of first cell temperatures of the plurality of battery cells; and a battery management system (BMS) that is configured to determine a wireless communication status with the CMC, diagnose the battery pack based on the plurality of first cell voltages and the plurality of first cell temperatures received from the CMC according to the wireless communication status with the CMC, and diagnose the battery pack by estimating a plurality of second cell voltages and a plurality of second cell temperatures of the plurality of battery cells.
  2. The battery system of claim 1, wherein: the BMS includes a main control unit (MCU) that derives cell voltage deviations of each of the plurality of battery cells based on a pack voltage of the battery pack and stores the derived cell voltage deviations in a memory, when the wireless communication status with the CMC is in a normal state; and a diagnostic unit that diagnoses the battery pack based on the plurality of first cell voltages and the plurality of first cell temperatures received from the CMC, when the wireless communication status with the CMC is in the normal state.
  3. The battery system of claim 2, wherein: the BMS further includes at least one input terminal that is electrically connected to at least one of two terminals of the battery pack, and the MCU determines, as the cell voltage deviations of each of the plurality of battery cells, a value obtained by subtracting each of the plurality of first cell voltages from a value obtained by dividing the pack voltage of the battery pack derived based on a pack voltage signal received from at least one of the two terminals of the battery pack by a number of the plurality of battery cells.
  4. The battery system of claim 1, wherein: the BMS further includes a cell voltage estimation unit that determines, as the plurality of second cell voltages, a value obtained by subtracting a cell voltage deviation stored in a normal state before an abnormal state of the wireless communication with the CMC from a value obtained by dividing a pack voltage of the battery pack derived from a pack voltage signal received from at least one of two terminals of the battery pack by a number of the plurality of battery cells, when the wireless communication with the CMC is in the abnormal state.
  5. The battery system of claim 1, further comprising: a cooling unit that includes an inlet into which a coolant is injected and an outlet through which the coolant is discharged to cool the battery pack by heat exchange with the battery pack through the coolant; a first temperature sensor that measures a temperature of the inlet of the cooling unit; a second temperature sensor that measures a temperature of the outlet of the cooling unit; and a current sensor that measures a pack current of the battery pack, wherein the BMS further includes: a first input terminal that is electrically connected to the first temperature sensor; a second input terminal that is electrically connected to the second temperature sensor; a third input terminal that is electrically connected to the current sensor; and a communication unit that receives the plurality of first cell voltages and the plurality of first cell temperatures received from the CMC via wireless communication.
  6. The battery system of claim 5, wherein: a memory pre-stores a lookup table that indicates cell temperature values according to ranges of the pack current and coolant temperature, respectively, through a pack test for the battery pack, the BMS further includes a cell temperature estimation unit that calculates the temperature of the coolant from the temperature of the inlet and the temperature of the outlet and derives a temperature of a plurality of second cells based on the temperature of the coolant, the pack current, and the lookup table, when the wireless communication with the CMC is in an abnormal state, and the diagnostic unit diagnoses the battery pack based on the plurality of second cell voltages and the plurality of second cell temperatures when the wireless communication with the CMC is in the abnormal state.
  7. A battery pack diagnosis method by a battery system that includes a battery pack including a plurality of battery cells, a cell monitoring controller (CMC) configured to monitor a plurality of first cell voltages and a plurality of first cell temperatures of the plurality of battery cells, and a battery management system (BMS) configured to diagnose the battery pack, the method comprising: determining a wireless communication status with the CMC; and diagnosing the battery pack based on the plurality of first cell voltages and the plurality of first cell temperatures received from the CMC according to the wireless communication status with the CMC and diagnosing the battery pack by estimating a plurality of second cell voltages and a plurality of second cell temperatures of the plurality of battery cells.
  8. The method of claim 7, further comprising: deriving cell voltage deviations of each of the plurality of battery cells based on a pack voltage of the battery pack and storing the derived cell voltage deviations in a memory, when the wireless communication with the CMC is in a normal state; and diagnosing the battery pack based on the plurality of first cell voltages and the plurality of first cell temperatures received from the CMC, when the wireless communication with the CMC is in the normal state.
  9. The method of claim 8, further comprising: determining, as the cell voltage deviations of each of the plurality of battery cells, a value obtained by subtracting each of the plurality of first cell voltages from a value obtained by dividing the pack voltage of the battery pack derived based on a pack voltage signal received from at least one of two terminals of the battery pack by a number of the plurality of battery cells, wherein the BMS further includes at least one input terminal that is electrically connected to at least one of the two terminals of the battery pack.
  10. The method of claim 7, further comprising: when the wireless communication with the CMC is in an abnormal state, deriving a pack voltage of the battery pack based on a pack voltage signal received from at least one of two terminals of the battery pack; and determining, as the plurality of second cell voltages, a value obtained by subtracting a cell voltage deviation stored in a normal state before the abnormal state of the wireless communication with the CMC from a value obtained by dividing the pack voltage of the battery pack by a number of the plurality of battery cells.
  11. The method of claim 7, further comprising: receiving a signal indicating a temperature of an inlet by a first input terminal electrically connected to a first temperature sensor measuring the temperature of the inlet of a cooling unit that includes the inlet into which a coolant is injected and an outlet through which the coolant is discharged to cool the battery pack by heat exchange with the battery pack through the coolant; receiving a signal indicating a temperature of the outlet by a second input terminal electrically connected to a second temperature sensor measuring the temperature of the outlet of the cooling unit; receiving a signal indicating a pack current by a third input terminal electrically connected to a current sensor measuring the pack current of the battery pack; and receiving the plurality of first cell voltages and the plurality of first cell temperatures received from the CMC via wireless communication.
  12. The method of claim 11, further comprising: when the wireless communication with the CMC is in an abnormal state, calculating a temperature of the coolant from the temperature of the inlet and the temperature of the outlet; deriving the plurality of second cell temperatures based on the temperature of the coolant, the pack current, and a lookup table; and diagnosing the battery pack based on the plurality of second cell voltages and the plurality of second cell temperatures when the wireless communication with the CMC is in the abnormal state, wherein a memory pre-stores the lookup table that indicates cell temperature values according to ranges of the pack current and the coolant temperature, respectively, through a pack test for the battery pack.

Description

[Technical Field] CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0188920 filed in the Korean Intellectual Property Office on December 21, 2023, and Korean Patent Application No. 10-2024-0052995 filed in the Korean Intellectual Property Office on April 19, 2024, the entire contents of which are incorporated herein by reference. The present disclosure relates to a battery system and a battery pack diagnosis method by supplementing a cell voltage and cell temperature data. [Background Art] A battery management system (BMS) may receive cell voltage and cell temperature values from a cell monitoring controller (CMC) that monitors the cell voltages and cell temperatures of each of a plurality of battery cells. The BMS and the CMC may communicate wirelessly. However, when the wireless connection with the CMC is poor, the BMS may not know the exact cell voltage and cell temperature, and thus may stop the supply of power to a battery pack. However, when the supply of power to the battery pack stops whenever the communication with the CMC is unstable, the utilization of the battery is unstable, so there is a need to supplement the cell voltage and cell temperature data due to the communication failure with the CMC in order to stably supply power. [Disclosure] [Technical Problem] The present disclosure attempts to provide a battery system capable of supplementing a cell voltage and cell temperature data when a wireless connection between a CMC and a BMS is unstable, and a battery pack diagnosis method by supplementing a cell voltage and cell temperature data. [Technical Solution] According to an aspect of the present disclosure, a battery system may include a battery pack that includes a plurality of battery cells, a cell monitoring controller (CMC) that is configured to monitor a plurality of first cell voltages and a plurality of first cell temperatures of the plurality of battery cells, and a battery management system (BMS) that is configured to determine a wireless communication status with the CMC, diagnose the battery pack based on the plurality of first cell voltages and the plurality of first cell temperatures received from the CMC according to the wireless communication status with the CMC, and diagnose the battery pack by estimating a plurality of second cell voltages and a plurality of second cell temperatures of the plurality of battery cells. The BMS may include a main control unit (MCU) that derives cell voltage deviations of each of the plurality of battery cells based on a pack voltage of the battery pack and stores the derived cell voltage deviations in a memory, when the wireless communication status with the CMC is in a normal state, and a diagnostic unit that diagnoses the battery pack based on the plurality of first cell voltages and the plurality of first cell temperatures received from the CMC, when the wireless communication status with the CMC is in the normal state. The BMS may further include at least one input terminal that is electrically connected to at least one of two terminals of the battery pack, and the MCU may determine, as the cell voltage deviations of each of the plurality of battery cells, a value obtained by subtracting each of the plurality of first cell voltages from a value obtained by dividing the pack voltage of the battery pack derived based on a pack voltage signal received from at least one of the two terminals of the battery pack by a number of the plurality of battery cells. The BMS may further include a cell voltage estimation unit that determines, as the plurality of second cell voltages, a value obtained by subtracting a cell voltage deviation stored in a normal state before an abnormal state of the wireless communication with the CMC from a value obtained by dividing a pack voltage of the battery pack derived from a pack voltage signal received from at least one of the two terminals of the battery pack by a number of the plurality of battery cells, when the wireless communication with the CMC is in the abnormal state. The battery system may further include a cooling unit that includes an inlet into which a coolant is injected and an outlet through which the coolant is discharged to cool the battery pack by heat exchange with the battery pack through the coolant, a first temperature sensor that measures a temperature of the inlet of the cooling unit, a second temperature sensor that measures a temperature of the outlet of the cooling unit, and a current sensor that measures a pack current of the battery pack, in which the BMS may further include a first input terminal that is electrically connected to the first temperature sensor, a second input terminal that is electrically connected to the second temperature sensor, a third input terminal that is electrically connected to the current sensor, and a communication unit that receives the plurality of first cell voltages and the plura