US-12627012-B2 - Thermal runaway prevention

US12627012B2US 12627012 B2US12627012 B2US 12627012B2US-12627012-B2

Abstract

A battery assembly can include a pair of batteries. The battery pair may be electrically coupled by a bimetallic strip. When the temperature of the battery assembly exceeds a threshold temperature, the bimetallic strip deforms so that the coupling between the first and second batteries breaks. In other cases, the battery pair may be coupled by a spring-loaded connector. A sacrificial block configured to melt if the temperature of the battery assembly increases beyond the threshold temperature may force the spring into an energy-storing configuration. When the sacrificial block melts, the spring is released, and the connector is forced in a direction away from the battery terminals. Finally, the battery assembly may include a thermopile and one or more relays. When a temperature gradient of the thermopile exceeds a threshold gradient, the thermopile generates a voltage that causes the relays to disconnect the battery assembly from a charging circuit.

Inventors

Surinder Singh
Ratnesh K. Sharma

Assignees

Relyion Energy Inc.

Dates

Publication Date: 20260512
Application Date: 20221021

Claims (14)

1 . A battery assembly comprising: a first battery comprising a first terminal; a second battery comprising a second terminal; a conductive connector comprising a first end and a second end, wherein the conductive connector electrically connects the first terminal to the second terminal; a spring mechanically coupled to the conductive connector; and a sacrificial block, distinct from the electrical connector, disposed on a surface of the conductive connector, wherein the sacrificial block forces the spring into an energy-storing configuration, wherein, when the spring is forced into the energy-storing configuration, the first end of the conductive connector is electrically and physically coupled to the first terminal and the second end of the conductive connector is electrically and physically coupled to the second terminal; wherein the sacrificial block is configured to melt when a battery assembly temperature exceeds a threshold temperature value such that, when the sacrificial block melts, the spring relaxes from the energy-storing configuration and mechanically displaces the conductive connector to break the electrical and physical coupling between the first end of the conductive connector and the first terminal and to break the electrical and physical coupling between the second end of the conductive connector and the second terminal.
2 . The battery assembly of claim 1 , wherein the first battery and the second battery are rechargeable.
3 . The battery assembly of claim 1 , wherein the spring is a helical spring.
4 . The battery assembly of claim 3 , wherein the energy-storing position is a compressed position.
5 . The battery assembly of claim 1 , wherein the spring is a torsion spring that is mechanically coupled to the conductive connector by an insulating shaft.
6 . The battery assembly of claim 5 , wherein the energy-storing position is a twisted position.
7 . The battery assembly of claim 1 , wherein the conductive connector comprises copper.
8 . The battery assembly of claim 1 , wherein the sacrificial block comprises a phase change material (PCM).
9 . The battery assembly of claim 1 , wherein the threshold temperature value is between 50° C. and 100° C.
10 . The battery assembly of claim 1 , wherein: the first terminal of the first battery is electrically coupled to a first relay, and the first battery further comprises a third terminal electrically coupled to a second relay, the battery assembly further comprising: a thermopile, wherein a hot junction of the thermopile is positioned proximate to the first battery and a cold junction of the thermopile is positioned distally from the first battery with respect to the hot junction and wherein the first relay and the second relay are electrically coupled to the thermopile; wherein the thermopile and the first and second relays are configured such that, when a temperature gradient of the thermopile exceeds a threshold gradient value, the thermopile generates a voltage that causes one or both of the first and second relays to disconnect one or both of the first and third terminals from a circuit.
11 . The battery assembly of claim 10 , wherein the circuit is a charging circuit for the first battery.
12 . The battery assembly of claim 10 , wherein the thermopile comprises a thermoelectric cell comprising iron and copper.
13 . The battery assembly of claim 10 , wherein the threshold gradient value is less than or equal to 0.3° C./inch.
14 . The battery assembly of claim 1 , wherein: the sacrificial block is aligned with the spring, and the disposing the sacrificial block on the surface and the aligning the sacrificial block with the spring force the spring into the energy-storing configuration.

Description

FIELD The present disclosure relates generally to systems for preventing thermal runway. BACKGROUND Thermal runaway is a well-known problem for battery assemblies. Many thermal runaway solutions involve complex cooling or fire prevention systems that are electronically controlled by a battery management system (BMS). SUMMARY As described above, many thermal runaway solutions involve complex cooling or fire prevention systems that are electronically controlled by a battery management system (BMS). Controlling the cooling or fire prevention systems requires the BMS to continuously extract data from the batteries in the battery assembly and process said data to detect anomalies. In other words, the prevention of thermal runaway is contingent upon the ability of the BMS to accurately and efficiently determine when thermal runway is occurring. Monitoring and analysis by a BMS system introduces the potential for failures due to inaccurate measurements, non-optimal control logic, slow response times, and/or other failures by the BMS system. Accordingly, there is a need for improved systems and methods for preventing thermal runaway in battery assemblies, including for systems and methods that allow prevention of thermal runaway without the need for reliance on electronic monitoring and control by a BMS system. Disclosed herein are systems and methods that may address one or more of the above-identified needs. Provided herein are battery assemblies with thermal runaway prevention mechanisms. The thermal runaway prevention mechanisms may include analog systems that are configured to prevent thermal runaway in battery assemblies without the aid of an electronic monitoring system such as a battery management system. In particular, the battery assemblies may be configured to break electrical coupling between two or more batteries or between a battery and another circuit when a temperature of the battery assembly exceeds a threshold temperature value. A first battery assembly may comprise a first battery comprising a first terminal, a second battery comprising a second terminal, a conductive connector electrically coupled the second terminal, and a bimetallic strip electrically coupled to the first terminal and to the conductive connector, wherein the bimetallic strip is configured to deform as a temperature of the bimetallic strip changes, such that deformation of the bimetallic strip will cause the bimetallic strip to disconnect from the conductive connector when the temperature of the bimetallic strip exceeds a first threshold temperature value. In some embodiments of the first battery assembly, the first battery and the second battery are rechargeable. In some embodiments of the first battery assembly, the conductive connector comprises copper. In some embodiments of the first battery assembly, the bimetallic strip comprises a first layer comprising steel and a second layer comprising copper. In some embodiments of the first battery assembly, wherein the first threshold temperature value is greater than or equal to 50° C. and less than or equal to 100° C. In some embodiments of the first battery assembly, deformation of the bimetallic strip will cause the bimetallic strip to deform in a direction away from the conductive connector when the temperature of the bimetallic strip exceeds a second threshold temperature value but does not exceed the first threshold temperature value, such that a contact area between the bimetallic strip and the conductive connector decreases as the bimetallic strip deforms. In some embodiments of the first battery assembly, the second threshold temperature value is greater than or equal to 30° C. and less than or equal to 50° C. A second battery assembly may comprise a first battery comprising a first terminal, a second battery comprising a second terminal, a conductive connector comprising a first end and a second end, a spring mechanically coupled to the conductive connector and a sacrificial block disposed on a surface of the conductive connector, wherein the sacrificial block forces the spring into an energy-storing configuration, wherein, when the spring is forced into the energy-storing configuration, the first end of the conductive connector is electrically coupled to the first terminal and the second end of the conductive connector is electrically coupled to the second terminal and wherein the sacrificial block is configured to melt when a battery assembly temperature exceeds a threshold temperature value such that, when the sacrificial block melts, the spring relaxes from the energy-storing configuration and mechanically displaces the conductive connector to break the electrical coupling between the first end of the conductive connector and the first terminal and the electrical coupling between the second end of the conductive connector and the second terminal. In some embodiments of the second battery assembly, the first battery and the second battery are rechargeable. In some em