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US-12626964-B2 - Thermal wakeup for battery management system controller

US12626964B2US 12626964 B2US12626964 B2US 12626964B2US-12626964-B2

Abstract

A monitoring circuit for a battery system of a work machine includes a system controller configured to operate in a low power mode when the battery system is inactive, a sensing circuit element configured to produce an electrical sensor signal representative of an environmental parameter of the battery system, and a wakeup circuit configured to generate a controller activation signal when the sensor signal indicates that the environmental parameter is outside of a specified operating range. The system controller is configured to initiate a controller boot operation in response to the controller activation signal.

Inventors

  • Matthew Lee Boggs
  • Jason Lee Miller

Assignees

  • CATERPILLAR INC.

Dates

Publication Date
20260512
Application Date
20220419

Claims (9)

  1. 1 . A monitoring circuit for a battery system of a work machine, the monitoring circuit comprising: a system controller configured to operate in a low power mode when the battery system is inactive; a sensing circuit element configured to produce an electrical sensor signal representative of an external environmental parameter of the battery system; a wakeup circuit configured to generate, when the battery system is in the low power mode, a controller activation signal to change the system controller from the low power mode to an active mode in response to the sensor signal indicating that the external environmental parameter is outside of a specified operating range; and wherein the system controller is configured to initiate a controller boot operation when transitioning from the low power mode to the active mode in response to the controller activation signal generated in response to the sensor signal.
  2. 2 . The monitoring circuit of claim 1 including: a bootstrap supply circuit to power an interface of the system controller to the sensing circuit element in the low power mode, wherein the bootstrap supply circuit provides power to circuits that are active in the low power mode; and a main supply circuit for the system controller that is activated in response to the controller activation signal.
  3. 3 . The monitoring circuit of claim 1 , wherein the sensing circuit element includes a temperature sensing circuit element, and the wakeup circuit includes a window comparator circuit, and the window comparator circuit is configured to generate the activation signal when the sensing circuit element indicates a temperature that is outside of a specified temperature range.
  4. 4 . The monitoring circuit of claim 3 , wherein the system controller is configured to initiate activation of a heating system for the one or more battery cells when the sensing circuit element indicates a temperature that is below a specified temperature range.
  5. 5 . The monitoring circuit of claim 3 , wherein the system controller is configured to initiate activation of a cooling system for the one or more battery cells when the sensing circuit element indicates a temperature that is greater than the specified temperature range.
  6. 6 . The monitoring circuit of claim 1 , wherein the sensing circuit element includes a fluid level sensing circuit element configured to generate an indication of fluid level of a nonconductive liquid coolant of one or more battery cells of the battery system, and the wakeup circuit includes a comparator circuit configured to generate the activation signal when the fluid sensing circuit element indicates a fluid level below a specified fluid level.
  7. 7 . The monitoring circuit of claim 2 , including: a reverse battery protection circuit; and an inductor-capacitor (LC) filter circuit coupled between the reverse battery protection circuit and the bootstrap supply circuit.
  8. 8 . The monitoring circuit of claim 1 including: a low pass filter circuit coupled to the sensing circuit element to produce a filtered sensor signal; and wherein the system controller is configured to enter an active mode in response to the controller activation signal and determine a corrective action using the filtered sensor signal when in the active mode.
  9. 9 . The monitoring circuit of claim 1 , including memory; and wherein the system controller is configured to store in the memory information associated with the environmental parameter being outside of the specified operating range in response to the controller activation signal.

Description

TECHNICAL FIELD This document relates to electric powered work machines and in particular to techniques of managing the battery systems of electric powered work machines. BACKGROUND Powering a large moving work machine (e.g., a wheel loader) with an electric motor requires a large mobile electric energy source that can provide current of hundreds of Amperes (Amps). This large mobile energy source can include multiple large capacity battery cells connected in parallel as battery strings that provide the sustained energy power needed by a large electric-powered moving work machine. It may be desirable to ensure that the performance or the lifetime of the large capacity battery cells aren't compromised by environmental conditions. SUMMARY OF THE INVENTION Electric powered large moving work machines use large capacity battery systems that may remain idle for periods of time when the work machine is not in use. It would be useful to avoid environmental conditions that can impact the performance and lifetime of the batteries, but monitoring the status of the battery system shouldn't impact battery life through extra energy drain. An example monitoring circuit for a battery system of a work machine includes a system controller configured to operate in a low power mode when the battery system is inactive, a sensing circuit element configured to produce an electrical sensor signal representative of an environmental parameter of the battery system, and a wakeup circuit configured to generate a controller activation signal when the sensor signal indicates that the environmental parameter is outside of a specified operating range. The system controller is configured to initiate a controller boot operation in response to the controller activation signal. An example method of monitoring a battery system of a work machine includes operating a system controller in a low power mode when the battery system is powered down, monitoring an environmental parameter of the battery system using the system controller in the low power mode, detecting when the environmental parameter is outside of a specified operating range, operating the system controller in an active mode in response to the detecting that the environmental parameter is outside of the specified operating range when the battery system is powered down, and the system controller initiating a corrective action to bring the environmental parameter to within the specified operating range. An example battery system of a work machine includes at least one battery pack including multiple battery cells; a system controller, and a monitoring circuit. The monitoring circuit includes a sensing circuit element configured to produce an electrical sensor signal representative of temperature of the battery cells, and a comparator circuit configured to generate a controller activation signal when the sensor signal indicates that the temperature of the battery cells is outside of a specified operating range. The system controller is configured to initiate a corrective action in response to the controller activation signal. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation view depicting an example work machine in accordance with this disclosure. FIG. 2 is a block diagram of a battery system for a work machine in accordance with this disclosure. FIG. 3 is a block diagram of portions of an example of an energy source for a work machine in accordance with this disclosure. FIGS. 4A-4B show detailed circuit schematics in accordance with this disclosure. FIG. 5 is a flow diagram of an example method of real time monitoring of the environment conditions of a battery system of a work machine in accordance with this disclosure. DETAILED DESCRIPTION Examples according to this disclosure are directed to methods and systems for automatic monitoring a battery system of a work machine. Monitoring the environmental conditions of the battery system allows for predictive maintenance to avoid negative impact on the performance of the battery system. FIG. 1 depicts an example machine 100 in accordance with this disclosure. In FIG. 1, machine 100 includes frame 102, wheels 104, implement 106, and a speed control system implemented in one or more on-board electronic devices like, for example, an electronic control unit or ECU. Example machine 100 is a wheel loader. In other examples, however, the machine may be other types of machines related to various industries, including, as examples, construction, agriculture, forestry, transportation, material handling, waste management, and so on. Accordingly, although a number of examples are described with reference to a wheel loader machine, examples according to this disclosure are also applicable to other types of machines including graders, scrapers, dozers, excavators, compactors, material haulers like dump trucks, along with other example machine types. Machine 100 includes frame 102 mounted on four wheels 104, although, in other examples, the machin