Method for detection of short circuits within an energy storage device

Patent metadata

Field	Value
Publication number	US-2016377667-A1
Application number	US-201615186642-A
Country	US
Kind code	A1
Filing date	Jun 20, 2016
Priority date	Jun 23, 2015
Publication date	Dec 29, 2016
Grant date	—

Abstract

A method for detecting a short circuit within an energy store. The method includeds registering a current which flows through the energy store, registering a first voltage which is made available by the energy store at a first time, registering a second voltage which is made available by the energy store at a second time following the first time, determining whether the energy store is in a state of charge, a discharge state or in an open-circuit state, executing a first detection step when the energy store is in an open-circuit state, a second detection step when the energy store is in a state of charge, and a third detection step when the energy store is in a discharged state, and determining whether a short circuit is present based on the first and second voltage.

First claim

1 . A method for detecting a short circuit within an energy store, the method comprising:
registering a current (I C ) which flows through the energy store, registering a first voltage (U n-1 ) which is made available by the energy store at a first time (t n-1 ), registering a second voltage (U n ) which is made available by the energy store at a second time (t n ) following the first time (t n-1 ), determining whether the energy store is in a state of charge, a discharge state or in an open-circuit state, on the basis of the registered first current (I C ), executing a first, second or third detection step on the basis of the determined state of charge, wherein in the first detection step, which is executed when the energy store is in the open-circuit state, a short circuit is detected as being present if the second voltage (U n ) is lower than the first voltage (U n-1 ) minus a first constant (ε 1 ), in the second detection step, which is executed when the energy store is in a state of charge, a short circuit is detected as being present if the second voltage (U n ) is lower than the first voltage (U n-1 ), and in the third detection step, which is executed when the energy store is in the discharge state, a short circuit is detected as being present if the second voltage (U n ) is lower than the first voltage (U n-1 ) minus a differential voltage (ΔU).

2 . The method according to claim 1 , wherein the differential voltage (ΔU) is a maximum change in voltage which results from a maximum discharge current of the energy store.

3 . The method according to claim 1 , wherein the differential voltage (ΔU) is an expected change in voltage which results from a measured discharge current of the energy store.

4 . The method according to claim 1 , wherein an internal resistance (R c ) of the energy store is estimated, and the differential voltage (ΔU) is acquired on the basis of the internal resistance (R c ).

5 . The method according to claim 1 , wherein in the second detection step, which is executed when the energy store is in a state of charge, a short circuit is detected as being present if the second voltage (U n ) is lower than the first voltage (U n-1 ) minus a second constant (ε 2 ).

6 . The method according to claim 1 , wherein in the third detection step, which is executed when the energy store is in the discharge state, a short circuit is detected as being present if the second voltage (U n ) is lower than the first voltage (U n-1 ) minus a differential voltage (ΔU) and minus a third constant (ε 3 ).

7 . A device configured to execute the method according to claim 1 .

8 . The device according to claim 7 , wherein the device comprises a capacitor (C) by which the first voltage (U n-1 ) is registered and held in reserve.

9 . The device according to claim 8 , wherein the device comprises a diode (D) which is connected in such a way that it permits charging of the capacitor (C) by a voltage which is made available by the energy store, but prevents discharging of the capacitor (C).

10 . The device according to claim 8 , wherein the device comprises a switch via which the capacitor (C) is connected in a disconnectable fashion to an output of the energy store.

Assignees

• Bosch Gmbh Robert
• Lithium Energy & Power Gmbh & Co Kg

Inventors

• Friedrich Marco
• Heil Matthias
• Butzmann Stefan
• Bernhardt Christian

Classifications

• G01R31/52

  Testing for short-circuits, leakage current or ground faults · CPC title

• G01R31/396 Primary

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

• G01R31/3842

  combining voltage and current measurements · CPC title

• G01R31/389

  Measuring internal impedance, internal conductance or related variables · CPC title

• G01R31/025 Primary

  Physics · mapped topic