Battery management system for determining charge transfer

Patent metadata

Field	Value
Publication number	US-2025323329-A1
Application number	US-202519174081-A
Country	US
Kind code	A1
Filing date	Apr 9, 2025
Priority date	Apr 10, 2024
Publication date	Oct 16, 2025
Grant date	—

Abstract

A battery management system can include a host microcontroller, which can be operated in accordance with a first clock signal, and an analog front end (AFE) circuit, where the AFE circuit can be operated in accordance with a second clock signal that can be unsynchronized with the first clock signal. The AFE circuit can include an input which can be configured to receive a representation of a battery current associated with one or more cells in a battery system. The AFE circuit can also include current measurement circuitry, included in or coupled to the AFE circuit, which can be configured to generate an average current value representative of an average of the battery current for a specified time period. The host microcontroller can be configured to determine a time value representative of a duration of the specified time period, and determine, based on the indication of the average current value, a current transfer value of the battery current during the specified time period.

First claim

What is claimed is:

1 . A battery management system comprising:
a host microcontroller, operated in accordance with a first clock signal; and an analog front end (AFE) circuit, wherein the AFE circuit is operated in accordance with a second clock signal that is unsynchronized with the first clock signal, the AFE circuit comprising:
an input configured to receive a representation of a battery current associated with one or more cells in a battery system;
current measurement circuitry, included in or coupled to the AFE circuit, the current measurement circuitry configured to generate an average current value representative of an average of the battery current for a specified time period; and
communication circuitry, configured to transmit an indication of the average current value to the host microcontroller;
wherein the host microcontroller is configured to:
determine a time value representative of a duration of the specified time period; and
determine, based on the indication of the average current value, a current transfer value of the battery current during the specified time period.

2 . The battery management system of claim 1 , wherein the host microcontroller is configured to:
determine the current transfer value at least in part by multiplying a representation of the time value by a representation of the indication of the average current value.

3 . The battery management system of claim 1 , wherein:
the AFE circuit determines the average current value in correspondence to a specified functional safety standard; and the host microcontroller determines the time value in correspondence to the specified functional safety standard.

4 . The battery management system of claim 3 , wherein the host microcontroller determines the current transfer value in correspondence to the specified functional safety standard.

5 . The battery management system of claim 3 , wherein the AFE circuit is configured to operate in accordance with the second clock signal that is unsynchronized with the first clock signal, without requiring that the second clock signal meet a specified functional safety standard for time determination included in the specified functional safety standard.

6 . The battery management system of claim 3 , wherein the first clock signal is generated using a circuit that has at least one of a higher power consumption or a larger circuit area as compared to a circuit that generates the second clock signal.

7 . The battery management system of claim 3 , wherein to determine the time value in correspondence to the specified functional safety standard includes cross checking time values from at least two of the following: an oscillator internal to the host microcontroller, a redundant oscillator internal to the host microcontroller, an oscillator external to the host microcontroller, or an oscillator included in another circuit.

8 . The battery management system of claim 1 , wherein the current measurement circuitry includes at least two redundant current counters, including respective current inputs and respective accumulation counters.

9 . The battery management system of claim 1 , the AFE circuit comprising:
a third clock signal input configured to receive a third clock signal, wherein the third clock signal operates at a different frequency than the second clock signal; and clock drift monitoring circuitry, configured to compare (1) a measured number of cycles of a higher frequency one of the second clock signal and the third clock signal during a specified number of cycles of a lower frequency one of the second clock signal and the third clock signal to (2) a reference number of cycles.

10 . The battery management system of claim 9 , wherein the clock drift monitoring circuitry is configured to:
determine the reference number of cycles by, at a beginning of the specified time period, measuring a number of cycles of a higher frequency one of the second clock signal and the third clock signal during a specified number of cycles of a lower frequency one of the second clock signal and the third clock signal; and, recurrently:
determine the measured number of cycles; and
compare the reference number of cycles to the measured number of cycles.

11 . The battery management system of claim 9 , wherein the clock drift monitoring circuitry is configured such that, in response to the measured number of cycles differing from the reference number of cycles by an amount greater than or equal to a threshold value, a clock drift is determined.

12 . The battery management system of claim 11 , wherein in response to determining clock drift, an estimated indication of a high-end inaccuracy on the average current value is determined and transmitted to the host microcontroller.

13 . The battery management system of claim 12 , wherein the estimated indication of the high-end inaccuracy is determined by multiplying an estimated clock drift value by a current accumulation counter value.

14 . The battery management system of claim 13 , the AFE circuit comprising:
a positive current counter, configured to accumulate a running total positive current value; and a negative current counter, configured to accumulate a running total negative current value, wherein the estimated indication of high-end inaccuracy is determined by multiplying the estimated clock drift value by a sum of the running total positive current value and the running total negative current value.

15 . The battery management system of claim 1 , wherein the AFE circuit comprises:
second current measurement circuitry, included in or coupled to the AFE circuit, the second current measurement circuitry configured to generate a second average current value representative of an average of the battery current for the specified time period; and current comparison circuitry, configured to compare the average current value to the second average current value.

16 . The battery management system of claim 1 , wherein the AFE circuit is configured to:
receive the representation of the battery current recurrently at a specified frequency, wherein the frequency is configurable by a user.

17 . A method of operating a battery management system, the method comprising:
receiving an input representation of a battery current associated with one or more cells in a battery system; determining an indication of average current value representative of an average of the battery current for a specified time period; determining a time value representative of a duration of the specified time period; and determining, based on the indication of average current value, a current transfer value of the battery current during the specified time period.

18 . The method of claim 17 , comprising using a host microcontroller operated in accordance with a first clock signal to determine the time value and an AFE circuit operated in accordance with a second clock signal that is unsynchronized with the first clock signal to determine the average current value.

19 . The method of claim 17 , wherein determining the current transfer value includes multiplying a representation of the time value by a representation of the indication of the average current value.

20 . A battery management system comprising:
a host microcontroller, operated in accordance with a first clock signal; and an analog front end (AFE) circuit, wherein the AFE circuit is operated in accordance with a second clock signal that is unsynchronized with the first clock signal, the AFE

Assignees

• Analog Devices International Unlimited Co

Inventors

• Shi Hongfei
• Gu Xiaoyun
• Lin Yijing
• Wang Yong
• Liao Dong
• Yang Ling
• Luo Rengui
• Li Dong
• Gao Chenhui
• Zhang Ming
• Bai Yiwei
• Zhao Ziwei
• Wang Tongxi
• Jin Yinji
• Li Dengrong
• Mai Zihao
• Yu Meng

Classifications

• H01M10/425 Primary

  Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing (printed circuits H05K1/00) · CPC title

• H01M2010/4271

  Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing · CPC title

• H01M2010/4278

  Systems for data transfer from batteries, e.g. transfer of battery parameters to a controller, data transferred between battery controller and main controller · CPC title

• H01M10/48 Primary

  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 title