Voltage measurement circuit and method, circuit board, and control module

Patent metadata

Field	Value
Publication number	US-12360168-B2
Application number	US-202318232839-A
Country	US
Kind code	B2
Filing date	Aug 11, 2023
Priority date	Dec 16, 2021
Publication date	Jul 15, 2025
Grant date	Jul 15, 2025

Abstract

A voltage measurement circuit for measuring a voltage output by a battery, the battery comprising n battery cells connected in series, wherein n is an integer greater than 1; and the circuit comprising: n low-voltage measurement modules provided in one-to-one correspondence with the n battery cells, a first switching circuit, a second switching circuit, a reference voltage source, and a control module, wherein the reference voltage source may be used for outputting a preset reference voltage; and the two ends of each of the low-voltage measurement modules may be connected to the two ends of a corresponding one of the battery cells via the first switching circuit, and the two ends of each of the low-voltage measurement modules may be further connected to the two ends of the reference voltage source via the second switching circuit.

First claim

The invention claimed is:

1. A voltage measurement circuit for measuring a voltage output by a battery, the battery comprising n battery cells connected in series, wherein n is an integer greater than 1; and
the circuit comprising: n first measurement structures provided in one-to-one correspondence with the n battery cells, a first switching circuit, a second switching circuit, a reference voltage source, and a controller, wherein the reference voltage source is configured to output a preset reference voltage;
the two ends of each of the first measurement structures are connected to the two ends of a corresponding one of the battery cells via the first switching circuit, the two ends of each of the first measurement structures are further connected to the two ends of the reference voltage source via the second switching circuit, and the controller is connected to switchers in the first switching circuit and the second switching circuit, and the controller is further connected to each of the first measurement structures; and
the controller is configured to control the switchers to be on or off and acquiring the voltages of the battery cells measured by the first measurement structures.

2. The voltage measurement circuit according to claim 1 , wherein the first switching circuit comprises n+1 first switchers; and
n−1 connection nodes formed by series connection of the n first measurement structures and the two ends of a branch circuit formed by series connection of the n first measurement structures are used as first connectable nodes, and n−1 connection nodes formed by series connection of the n battery cells and the two ends of a branch circuit formed by series connection of the n battery cells are used as second connectable nodes, the first connectable nodes being separately connected to corresponding ones of the second connectable nodes via the first switchers.

3. The voltage measurement circuit according to claim 2 , wherein the second switching circuit comprises n+2 second switchers; and
n−1 connection nodes formed by series connection of n second switchers and the two ends of a branch circuit formed by series connection of n second switchers are used as third connectable nodes, the first connectable nodes being separately connected to corresponding ones of the third connectable nodes via the second switchers, and the two ends of a branch circuit formed by series connection of the second switchers are further connected to the two ends of the reference voltage source via the second switchers.

4. The voltage measurement circuit according to claim 1 , wherein the second switching circuit comprises 2n second switchers; and
the two ends of each of the n first measurement structures are connected at the two ends of the reference voltage source via the second switchers.

5. The voltage measurement circuit according to claim 1 , wherein
the controller is configured to control switchers in the second switching circuit, so as to control switchers in the first switching circuit in the case where the first measurement structures are all disconnected from the reference voltage source, and to obtain voltages U 1 , U 2 , . . . , and U n of the corresponding battery cells through measurement by the first measurement structures;
the controller is further configured to control the switchers in the first switching circuit, so as to control the switchers in the second switching circuit in the case where the first measurement structures are all disconnected from the battery cells, and to obtain voltages V 1 , V 2 , . . . , and V n output by the reference voltage source through measurement by the first measurement structures, respectively; and
the controller is further configured to calculate differences between V 1 , V 2 , . . . , and V n and the preset reference voltage separately to obtain errors σv 1 , σv 2 , . . . , and σv n of the first measurement structures, and calibrate U 1 , U 2 , . . . , and U n according to σv 1 , σv 2 , . . . , and σv n to obtain U 1 ′, U 2 ′, . . . , and U n ′, and use U sum obtained by summing up U 1 ′, U 2 ′, . . . and U n ′ as a voltage output by the battery that is obtained through measurement.

6. The voltage measurement circuit according to claim 5 , wherein the voltage measurement circuit further comprises a second measurement structure, the two ends of the second measurement structure being connected to the two ends of the battery, and the controller being further connected to the second measurement structure;
the second measurement structure is configured to measure the voltage output by the battery to obtain V total ; and
the controller is configured to use U sum as the voltage output by the battery that is obtained through measurement when |V sum -U sum | total sum is greater than a permissible error of the second measurement structure.

7. The voltage measurement circuit according to claim 5 , wherein the controller is further configured to calibrate U 1 , U 2 , . . . , and U n according to the equation U n ′=U n -|σv n | when |σv n |>σ allow and σv n ≥0; calibrate U 1 , U 2 , . . . , and U n according to the equation U n ′=U n +|σv n | when |σv n |>σ allow and σv n <0; and set U n ′=U n when σv n ≤σ allow , to obtain U 1 ′, U 2 ′, . . . , and U n ′, wherein σ allow is a set permissible error of the first measurement structures.

8. The voltage measurement circuit according to claim 7 , wherein the σ allow is the smaller one of a first permissible error and a second permissible error, wherein the first permissible error is the maximum permissible error of the first measurement structures modules and the second permissible error is |σv total |/n and |σv total | is the maximum permissible error of the second measurement structure.

9. The voltage measurement circuit according to claim 5 , wherein the controller is further connected to the reference voltage source, and the controller is further configured to set the preset reference voltage V REF =(V 1 +V 2 + . . . +V n )/n.

10. A circuit board, comprising the voltage measurement circuit of claim 1 .

11. A voltage measurement method that is based on a controller in a voltage measurement circuit for measuring a voltage output by a battery, the battery comprising n battery cells connected in series, wherein n is an integer greater than 1, wherein the voltage measurement circuit comprising: n first measurement structures provided in one-to-one correspondence with the n battery cells, a first switching circuit, a second switching circuit, a reference voltage source, and a controller, wherein the reference voltage source is configured to output a preset reference voltage;
the two ends of each of the first measurement structures are connected to the two ends of a corresponding one of the battery cells via the first switching circuit, the two ends of each of the first measurement structures are further connected to the two ends of the reference voltage source via the second switching circuit, and the controller is connected to switchers in the first switching circuit and the second switching circuit, and the controller is further connected to each of the first measurement structures; and
the controller is configured to control the switchers to be on or off and acquiring the voltages of the battery cells measured by the first measurement structures,
the method comprising:
controlling switchers in the first switching circuit and the second switching circuit to be on or off, and acquiring voltages of battery cells that are measured by the first measurement structures.

12. The voltage measurement method according to claim 11 , wherein the controlling switchers in the first switching circuit and the se

Assignees

• Contemporary Amperex Technology Hong Kong Ltd

Inventors

• Ma Guobin

Classifications

• G01R31/396 Primary

  Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery · CPC title

• G01R31/374

  with means for correcting the measurement for temperature or ageing · CPC title

• G01R19/10

  Measuring sum, difference or ratio · CPC title

• G01R1/206

  Switches for connection of measuring instruments or electric motors to measuring loads (switches in general H01H) · CPC title

• G01R19/0084

  Measuring voltage only · CPC title