Battery modules for determining temperature and voltage characteristics of electrochemical cells, and associated methods
A method for determining a temperature characteristic of an electrochemical cell assembly includes (1) sensing a first voltage via one or more thermistors electrically coupled to the electrochemical cell assembly while loading circuitry electrically coupled to the thermistors is deactivated, (2) sensing a second voltage via the one or more thermistors while the loading circuitry is activated, and (3) determining the temperature characteristic of the electrochemical cell assembly at least partially from the first and second voltages.
1 . A method for determining a temperature characteristic of an electrochemical cell assembly, the method comprising:
sensing a plurality of voltages at different respective sensing times using a voltage sensing device, each voltage of the plurality of voltages representing a respective voltage between a first sensing terminal of the voltage sensing device and a second sensing terminal of the voltage sensing device, the electrochemical cell assembly including one or more electrochemical cells and one or more thermistors, each thermistor of the one or more thermistors being electrically coupled in series with the one or more electrochemical cells between the first sensing terminal of the voltage sensing device and the second sensing terminal of the voltage sensing device;
repeatedly switching a magnitude of current flowing through the one or more thermistors between a first value and a second value, thereby causing magnitude of current flowing through the one or more thermistors to differ between at least two successive sensing times; and
determining, from the plurality of voltages, each of (a) the temperature characteristic of the electrochemical cell assembly and (b) magnitude of a voltage across the one or more electrochemical cells, the voltage across the one or more electrochemical cells being different from respective voltages across the one or more thermistors.
2 . The method of claim 1 , wherein:
the plurality of voltages comprises a first voltage sensed by the voltage sensing device when the magnitude of current flowing through a first thermistor of the one or more thermistors is the first value; and
the plurality of voltages further comprises a second voltage sensed by the voltage sensing device when a magnitude of current flowing through the first thermistor is the second value.
3 . The method of claim 2 , wherein a difference between the first and second voltages is at least partially a function of temperature of the one of more thermistors.
4 . The method of claim 2 , wherein the temperature characteristic is a function of a ratio of the first voltage to the second voltage.
5 . The method of claim 1 , wherein one of the first value and the second value is zero.
6 . The method of claim 1 , wherein the one or more thermistors are thermally coupled with the one or more electrochemical cells of the electrochemical cell assembly.
7 . The method of claim 1 , wherein repeatedly switching the magnitude of current flowing through the one or more thermistors between the first value and the second value comprises varying an operating state of loading circuitry electrically coupled to the one or more thermistors.
8 . The method of claim 7 , wherein the loading circuitry is configured to balance a state of charge of the electrochemical cell assembly.
9 . The method of claim 1 , wherein the temperature characteristic of the electrochemical cell assembly is an absolute temperature of the electrochemical cell assembly.
10 . The method of claim 1 , wherein the temperature characteristic of the electrochemical cell assembly is a relative temperature of the electrochemical cell assembly.
11 . The method of claim 1 , further comprising bypassing a first thermistor of the one or more thermistors by closing a switch electrically coupled in parallel with the first thermistor, while sensing one or more of the plurality of voltages.
12 . A method for determining a temperature characteristic of an electrochemical cell assembly, the method comprising:
obtaining a plurality of voltage measurements using a voltage sensing device, each voltage measurement representing a respective voltage between a first sensing terminal of the voltage sensing device and a second sensing terminal of the voltage sensing device, the electrochemical cell assembly including one or more thermistors and one or more electrochemical cells, the one or more thermistors being electrically coupled in series with one or more electrochemical cells between the first sensing terminal of the voltage sensing device and the second sensing terminal of the voltage sensing device;
using loading circuitry electrically coupled to the one or more thermistors, repeatedly switching magnitude of current flowing through the one or more thermistors between a first value and a second value, thereby causing magnitude of current flowing through the one or more thermistors to differ between at least two successive voltage measurements of the plurality of voltage measurements; and
determining, from the plurality of voltage measurements, each of (a) the temperature characteristic and (b) magnitude of a voltage across the one or more electrochemical cells, the voltage across the one or more electrochemical cells being different from respective voltages across the one or more thermistors.
13 . The method of claim 12 , wherein:
the plurality of voltage measurements comprises (a) a first voltage measurement having a first value and (b) a second voltage measurement having a second value; and
a difference between the first and second values is at least partially a function of temperature of the one or more thermistors.
14 . The method of claim 13 , wherein the temperature characteristic is a function of a ratio of the first value to the second value.
15 . The method of claim 12 , wherein the one or more thermistors are thermally coupled with the one or more electrochemical cells of the electrochemical cell assembly.