# US 7,609,032 B2 · Device and method for ascertaining the temperature in an electrical battery

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- Number: US 7,609,032 B2
- Document ID: US7609032B2
- Status: Granted
- Kind: B2
- Application number: 11/346,553
- Filed: 2006-02-02
- Published: 2006-09-14
- Granted: 2009-10-27
- Earliest claimed: 2005-02-03
- Assignees: VB Autobatterie GmbH & Co. KGaA
- Inventors: Helmut Laig-Hoerstebrock; Sepher Shirazi
- Web page: https://patentgrep.com/patent/US7609032B2

## CPC

- G01K 7/42: Circuits effecting compensation of thermal inertia; Circuits for predicting the stationary value of a temperature
- H01M 10/486: {for measuring temperature}
- Y02E 60/10: Energy storage using batteries
- G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00)
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A method for ascertaining the temperature in an electrical battery includes determining at least one temperature value at a temperature measuring point outside the battery in the vicinity of the battery; determining at least one electrical power value in dependence on a characteristic power variable associated with the operation of the battery; weighting the power values and the temperature values with an assigned weighting factor; and ascertaining the temperature in the electrical battery from an energy balance in dependence on the at least one weighted temperature value and the weighted electrical power values.

## Claims

### Claim 1

A method for ascertaining the temperature in an electrical battery using a measuring circuit comprising:
receiving at least one temperature value from a temperature sensor at a temperature measuring point outside the battery in the vicinity of the battery;
determining at least one electrical power value in dependence on a characteristic power variable associated with the operation of the battery;
using the measuring circuit to assign the power values and the temperature values with a weighting factor; and
using the measuring circuit to ascertain the temperature in the electrical battery from an energy balance equation in dependence on the at least one weighted temperature value and the weighted electrical power values.

### Claim 2 (depends on 1)

The method of claim 1, further comprising integrating over time at least one electrical power value and at least one temperature value.

### Claim 3 (depends on 1)

The method of claim 1, further comprising normalizing the at least one power value and continuously summing the at least one normalized power value and at least one temperature value in discrete time steps from the immediately previously ascertained battery temperature to ascertain the current battery temperature.

### Claim 4 (depends on 1)

The method of claim 1, wherein the weighting factor is chosen in dependence on the current operating state of the battery.

### Claim 5 (depends on 1)

The method of claim 1, wherein a characteristic power variable is the battery terminal current that can be measured at the battery terminals.

### Claim 6 (depends on 1)

The method of claim 1, wherein the power values and temperature values are related to the thermal capacity of the battery.

### Claim 7 (depends on 1)

The method of claim 1, wherein the temperature values are related to the thermal capacity of an assigned object at which the temperature is determined.

### Claim 8 (depends on 1)

The method of claim 1, wherein the power values and temperature values are related to the sum of the thermal capacity of the battery and at least one further thermal capacity of an object contributing to the temperature equalization.

### Claim 9 (depends on 1)

The method of claim 1, wherein the temperature value of an object contributing to the temperature equalization is determined with a system of equations of the kind:
TO=TO-1+(kO1·TB+kO2·TMess−kO0·TO-1)/COdt
and
kO1+kO2=kO0
where CO is the thermal capacity of the object, TB is the battery temperature, TMess is the temperature measured at the temperature measuring point, TO-1 is the temperature value of the object determined previously in time and kO1, kO2 and kO0 are fixed constants.

### Claim 10 (depends on 1)

The method of claim 1, further comprising ascertaining the battery temperature with a system of equations of the kind
T
B
=
T
B
-
1
+
N
/
C
B
·
dt
+
{
∑
i
=
1
n
⁢
k
1
·
T
1
-
k
0
·
T
B
-
1
}
/
C
B
·
dt
where TB-1 is the previously calculated battery temperature TB, CB is the thermal capacity of the battery, ki with i=1 to n are the weighting factors and Ti is at least one (if n=1) temperature value measured at objects i in the vicinity of the battery, and where N is the power value.

### Claim 11 (depends on 10)

The method of claim 10, wherein the sum of the weighting factors
∑
i
=
1
n
⁢
k
1
is equal to the weighting factor ko for the previously ascertained battery temperature.

### Claim 12 (depends on 1)

The method of claim 1, wherein the power value is calculated with a system of equations
N
=
N
B
+
∑
j
=
1
m
⁢
k
j
⁢
·
N
j
where NB is a value proportional to the electrical power converted by the battery, NJ are values proportional to powers converted by components in the vicinity of the battery, and kj are weighting factors.

### Claim 13 (depends on 12)

The method of claim 12, wherein the power value proportional to the power converted by the battery is the product of the battery terminal current and the difference between the battery terminal voltage and the battery open-circuit voltage.

### Claim 14 (depends on 13)

The method of claim 13, wherein the battery open-circuit voltage value is corrected by a constant voltage value characteristic of the battery system.

### Claim 15 (depends on 14)

The method of claim 14, wherein the constant voltage value for a lead-acid storage battery is in the range from −0.04 to −0.08 V/cell.

### Claim 16 (depends on 1)

The method of claim 1, wherein a further electrical power value describes the power converted by a shunt introduced into the battery circuit, and the shunt power value is calculated as the product of the shunt resistance and the square of the battery terminal current.

### Claim 17 (depends on 1)

The method of claim 1, wherein a further electrical power value is the electrical power converted in a measuring circuit, and this electrical power is determined in dependence on the current and voltage measured at the measuring circuit.

### Claim 18 (depends on 1)

The method of claim 1, wherein the weighting factor is dependent on the heat transfer values of the battery and the heat transfer values of the vicinity of an assigned object at which the temperature is determined.

### Claim 19 (depends on 1)

The method of claim 1, wherein the weighting factors are chosen based on the specific vicinity, on the type of a motor vehicle, and on the type of battery.

### Claim 20

A device for ascertaining the temperature in an electrical battery comprising:
at least one temperature sensor arranged outside a battery in the vicinity of the battery;
a voltmeter for measuring battery terminal voltage; and
a device for ascertaining battery terminal current and having an evaluation unit, which is connected to the at least one temperature sensor, the voltmeter, and the device for ascertaining the battery terminal current, and is designed for carrying out a method comprising the steps of:
determining at least one temperature value at a temperature measuring point outside the battery in the vicinity of the battery;
determining at least one electrical power value in dependence on a characteristic power variable associated with the operation of the battery;
assigning the power values and the temperature values with a weighting factor; and
determining the temperature in the electrical battery from an energy balance equation in dependence on the at least one weighted temperature value and the weighted electrical power values.