Battery protection systems for detecting conductive liquid ingress and associated devices and methods

Patent metadata

Field	Value
Publication number	US-12051926-B2
Application number	US-202218047521-A
Country	US
Kind code	B2
Filing date	Oct 18, 2022
Priority date	Jan 8, 2021
Publication date	Jul 30, 2024
Grant date	Jul 30, 2024

Abstract

This application is directed to an electronic device powered by one or more rechargeable battery cells. The electronic device includes a first negative temperature coefficient (NTC) thermistor proximate to the battery cells, and an open capacitor coupled in parallel with the NTC thermistor. The open capacitor has an open area and two electrodes that are at least partially exposed via the open area and electrically isolated. The electronic device further includes a control circuit coupled to the NTC thermistor and the open capacitor. The control circuit is configured to detect a voltage drop across the NTC thermistor and the open capacitor if conductive liquid enters the open area of the capacitor and electrically connects the two electrodes that are at least partially exposed via the open area.

First claim

What is claimed is:

1. An electronic device comprising:
a housing;
a first thermistor;
a capacitor electrically coupled to the first thermistor, the capacitor and the first thermistor electrically coupled in series or in parallel, the capacitor having two electrodes that are configured to be electrically isolated and are at least partially exposed in an open area within the housing; and
a control circuit configured to detect a first voltage drop across at least one of the first thermistor or the capacitor if an ingress contaminant electrically connects the two electrodes.

2. The electronic device of claim 1 , wherein the electronic device further comprises:
a second thermistor, the second thermistor physically isolated from the first thermistor and the capacitor; and
one or more processors, the one or more processors configured to obtain:
first information indicative of the first voltage drop across at least one of the first thermistor or the capacitor; and
second information indicative of a second voltage drop across the second thermistor.

3. The electronic device of claim 2 , wherein the one or more processors are configured to:
calculate, responsive to obtaining the first information and the second information, a difference between the first voltage drop and the second voltage drop; and
determine, based on the difference, that the first voltage drop is in response to the ingress contaminant electrically connecting the two electrodes.

4. The electronic device of claim 3 , wherein the determination comprises:
identifying whether a difference between the first voltage drop and the second voltage drop exceeds a threshold amount; or
identifying, based on the second information, whether the second voltage drop is below a threshold amount.

5. The electronic device of claim 3 , wherein the one or more processors are further configured to:
generate, based on a determination that the first voltage drop is in response to the ingress contaminant, a message indicative of a warning of ingress contaminants in the housing of the electronic device.

6. The electronic device of claim 5 , wherein the one or more processors are further configured to:
transmit the message to a client device via one or more communication networks for display on a user application executed on the client device; or
output the message via a speaker of the electronic device.

7. The electronic device of claim 2 , wherein the second information indicative of the second voltage drop indicates that the second voltage drop is zero.

8. The electronic device of claim 2 , wherein the second thermistor and the one or more processors are packaged on the control circuit.

9. The electronic device of claim 2 , wherein:
the first thermistor is exposed to air, and
the second thermistor is covered by an insulation material.

10. The electronic device of claim 2 , wherein the one or more processors are further configured to:
identify a voltage drop limit corresponding to a temperature increase internal to the housing of the electronic device;
compare the voltage drop across at least one of the first thermistor or the capacitor with the voltage drop limit; and
determine whether the voltage drop exceeds the voltage drop limit.

11. The electronic device of claim 1 , wherein the two electrodes of the capacitor are interdigitated and formed with the same conductive layer on a substrate.

12. The electronic device of claim 1 , wherein the electronic device further includes one or more rechargeable batteries.

13. The electronic device of claim 12 , further comprising:
a fuse component electrically coupled to a charging and discharging path of the one or more rechargeable batteries; and
wherein the control circuit, responsive to a detection of the first voltage drop across at least one of the first thermistor or the capacitor due to an ingress contaminant electrically connecting the two electrodes, is configured to generate a fuse enable signal to activate the fuse component effective to disconnect the charging and discharging path.

14. The electronic device of claim 12 , further comprising:
a switching component coupled in series with the one or more rechargeable batteries on a charging and discharging path, the control circuit configured to control the switching component to manage charging and discharging of the one or more rechargeable batteries via the charging and discharging path.

15. The electronic device of claim 14 , wherein the control circuit is configured to control the switching component to disable charging and discharging of the one or more rechargeable batteries when the first voltage drop across at least one of the first thermistor or the capacitor exceeds a threshold voltage drop.

16. The electronic device of claim 12 , wherein the first thermistor and the capacitor are packaged inside the one or more rechargeable batteries.

17. The electronic device of claim 1 , wherein the first thermistor is a negative temperature coefficient (NTC) thermistor.

18. The electronic device of claim 1 , wherein the ingress contaminant comprises at least one of an electrically conductive liquid or solid.

19. The electronic device of claim 1 , the control circuit is further configured to:
determine a temporal drop rate of the voltage drop across at least one of the first thermistor or the capacitor; and
determine whether the voltage drop is caused by the ingress contaminant or a change in temperature.

20. The electronic device of claim 2 , wherein the first thermistor is electrically coupled to the second thermistor in series.

Assignees

• Google Llc

Inventors

• Lim James Robert
• Zhang Haoxing
• Wang David
• Ho Dietrich Shing-Quan
• Song Yuanyuan

Classifications

• H02J7/50

  acting upon multiple batteries simultaneously or sequentially · CPC title

• H02J7/663 Primary

  using battery or load disconnect circuits (H02J9/002 takes precedence) · CPC title

• H02J7/977

  of the battery · CPC title

• H02J7/65

  against overtemperature · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title