Battery system with parallel joining protection

Patent metadata

Field	Value
Publication number	US-12418053-B2
Application number	US-202017638287-A
Country	US
Kind code	B2
Filing date	Aug 27, 2020
Priority date	Aug 28, 2019
Publication date	Sep 16, 2025
Grant date	Sep 16, 2025

Abstract

A battery pack includes a housing having a positive terminal and a negative terminal. Battery cells are located within the housing and are selectively coupled to the positive terminal and coupled to the negative terminal. A battery management system is located within the housing and is configured to operate a first switch within the housing to selectively couple the battery cells and the positive terminal. A bleed circuit is electrically coupled between the positive terminal and the negative terminal. The bleed circuit includes a resistor and a second switch to selectively couple the positive terminal to the negative terminal. The battery management system is configured to open the first switch and close the second switch and measure a voltage drop across the resistor to detect a presence and type of voltage source connected to the positive terminal.

First claim

What is claimed is:

1. A battery pack comprising:
a housing having a positive terminal and a negative terminal;
a plurality of battery cells located within the housing and selectively coupled to the positive terminal and coupled to the negative terminal;
a battery management system located within the housing and configured to operate a first switch within the housing to selectively couple the plurality of battery cells and the positive terminal; and
a bleed circuit electrically coupled between the positive terminal and the negative terminal, the bleed circuit including a resistor and a second switch to selectively couple the positive terminal to the negative terminal;
wherein the battery management system is configured to:
open the first switch and close the second switch and measure a voltage drop across the resistor to detect a presence of a voltage source connected to the positive terminal; and
determine, based on the measured voltage drop, whether the voltage source is capacitive.

2. The battery pack of claim 1 , wherein the battery management system measures the voltage drop across the resistor by comparing a first measured voltage to a second measured voltage, the second measured voltage being measured at a time interval after the first measured voltage.

3. The battery pack of claim 2 , wherein the battery management system determines whether the voltage source connected to the positive terminal is capacitive by comparing the first measured voltage to the second measured voltage and determining if a difference between the first measured voltage and the second measured voltage exceeds a threshold value.

4. The battery pack of claim 3 , wherein the battery management system determines that the voltage source is capacitive if the difference between the first measured voltage and the second measured voltage exceeds the threshold value.

5. The battery pack of claim 3 , wherein the battery management system determines that the voltage source is a battery if the difference between the first measured voltage and the second measured voltage does not exceed the threshold value.

6. The battery pack of claim 3 , wherein the battery management system is configured to open the second switch and close the first switch in response to determining that the difference between the first measured voltage and the second measured voltage exceeds the threshold value to couple the battery cells to the positive terminal and decouple the bleed circuit from the positive terminal.

7. The battery pack of claim 1 , further comprising a third switch within the housing and in communication with the battery management system, the third switch being positioned in series with the first switch and the positive terminal and positioned in series with the bleed circuit, wherein when the third switch is open, the bleed circuit is decoupled from the positive terminal and wherein when the third switch is closed, at least a portion of the bleed circuit is coupled with the positive terminal.

8. The battery pack of claim 7 , wherein the battery management system senses the voltage source connected to the positive terminal by comparing voltage signals upstream of the third switch and downstream of the third switch when the third switch is open and the second switch is closed.

9. The battery pack of claim 7 , wherein after the battery management system detects the voltage source is connected to the positive terminal, the battery management system is configured to close the third switch to electrically couple the bleed circuit to the positive terminal to detect a type of the voltage source connected to the positive terminal, the type of the voltage source being determined by comparing measured voltage drop across the resistor over a time period and comparing the measured voltage drop to a threshold value.

10. The battery pack of claim 9 , wherein the battery management system is configured to close the first switch, open the second switch, and close the third switch to couple the battery cells to the positive terminal upon detecting that the voltage source is capacitive.

11. The battery pack of claim 9 , wherein the battery management system is configured to close the first switch, open the second switch, and close the third switch to couple the battery cells to the positive terminal upon detecting that the voltage source is a battery having a discharge voltage within a predetermined range.

12. The battery pack of claim 9 , wherein the battery management system is configured to maintain the first switch open upon detecting that the voltage source is a battery having a discharge voltage outside a predetermined range.

13. The battery pack of claim 1 , wherein the battery management system is coupled to a controller area network bus (CANbus) link, the CANbus link configured to communicate a state of charge of the battery pack with additional battery packs.

14. A battery pack comprising:
a housing including a positive terminal and a negative terminal;
a plurality of battery cells received within the housing and selectively coupled to the positive terminal and coupled to the negative terminal;
a battery management system received within the housing and configured to operate a primary contactor switch and a secondary contactor switch to selectively couple the plurality of battery cells and the positive terminal; and
a bleed circuit extending between the positive terminal and the negative terminal, the bleed circuit including a resistor and a bleed switch to selectively couple the positive terminal to the negative terminal;
wherein the battery management system is configured to determine a presence of a voltage source on the positive terminal when the secondary contactor switch is in an open position;
wherein the battery management system is configured to determine a type of the voltage source on the positive terminal when the secondary contactor switch is in a closed position and the bleed switch is in a closed position.

15. The battery pack of claim 14 , wherein the battery management system determines the type of the voltage source on the positive terminal when the primary contactor switch is in an open position such that the battery cells are decoupled from the positive terminal.

16. The battery pack of claim 14 , wherein the battery management system is configured to open the bleed switch, close the primary contactor switch, and close the secondary contactor switch upon determining that no voltage source is present on the positive terminal to couple the battery cells to the positive terminal.

17. The battery pack of claim 14 , wherein the battery management system is configured to close the primary contactor switch and close the secondary contactor switch to couple the battery cells to the positive terminal when the voltage source is either capacitive or battery-based.

18. The battery pack of claim 17 , wherein the battery management system is configured to maintain at least one of the primary contactor switch and the secondary contactor switch in the open position to prevent the battery cells from being coupled to the positive terminal if a battery-based voltage source is detected on the positive terminal outside of a predetermined voltage range.

19. A battery system comprising:
a first battery pack coupled to a terminal bus and providing a voltage to the terminal bus; and
a second battery pack coupled to the terminal bus, the second battery pack comprising:
a positive terminal and a negative terminal,
a bleed circuit selectively coupled to the negative terminal,
one or mo

Assignees

• Briggs & Stratton Llc

Inventors

• Marshall Michael
• Schmalz Jacob

Classifications

• H02J7/96

  in response to battery voltage · CPC title

• H02J7/82 Primary

  Control of state of charge [SOC] · CPC title

• H02J7/44

  between battery management systems and power sources · CPC title

• H02J7/80

  including monitoring or indicating arrangements · CPC title

• H02J7/663

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