Vehicle battery protection device, and method for thermal management of same

1 . A vehicle battery protection device electrically connectable between a vehicle battery and a vehicle electrical system for preserving the state of charge of the vehicle battery, the vehicle battery protection device comprising:

a positive connector configured to be placed in electrical communication with a positive terminal of the vehicle battery;

a negative connector configured to be placed in electrical communication with a negative terminal of the vehicle battery;

a primary vehicle connector configured to be placed in electrical communication with a vehicle terminal of the vehicle electrical system;

a solid state switch commandable between an on state and an off state, the on state allowing current to flow between the vehicle battery and the vehicle electrical system through the solid state switch, and the off state preventing current from flowing between the vehicle battery and the vehicle electrical system through the solid state switch;

a switch temperature sensor configured to measure switch temperature at the solid state switch;

a battery voltage sensor configured to measure battery voltage between the positive connector and the negative connector;

a current sensor configured to measure switch current defined by the current flowing through the solid state switch;

one or more processors; and

a memory storing one or more programs configured to be executed by the one or more processors, the one or more programs including instructions for executing a thermal safety algorithm, the thermal safety algorithm comprising a switch derating process including the steps of:

selecting, from a plurality of distinct safe operating area datasets pertaining to the solid state switch, a safe operating area dataset corresponding to the switch temperature; and

limiting the on state based on the selected safe operating area dataset, the battery voltage, and the switch current;

wherein the vehicle battery protection device further comprises a main enclosure having one or more thermal chambers defined therein, each thermal chamber being in thermal communication with a corresponding sensor configured to obtain chamber temperature data from the thermal chamber; and

wherein the thermal safety algorithm further comprises a thermal analysis calibration including

referencing a thermal model, the thermal model being defined at least in part by materials-based and geometry-based thermal properties of the vehicle battery protection device; and

calculating, for each of the one or more thermal chambers, heat flux values based on

the thermal model; and

the chamber temperature data.

2 . The vehicle battery protection device of claim 1 , wherein

a first said thermal chamber houses the solid state switch and the switch temperature sensor;

a second said thermal chamber houses at least one of the one or more processors and a processor temperature sensor;

the switch temperature sensor is

the sensor configured to obtain the chamber temperature data from the first thermal chamber; and

the processor temperature sensor is

configured to measure processor temperature of at least one of the one or more processors; and

the sensor configured to obtain the chamber temperature data from the second thermal chamber.

3 . The vehicle battery protection device of claim 2 , wherein the calculating of the heat flux values is further based on ambient temperature of an environment external to the main enclosure.

4 . The vehicle battery protection device of claim 3 , wherein the one or more processors are configured to derive the ambient temperature from the chamber temperature data obtained from the second thermal chamber.

5 . The vehicle battery protection device of claim 3 further comprising an ambient temperature sensor for measuring the ambient temperature.

6 . The vehicle battery protection device of claim 5 , wherein the thermal analysis calibration further includes

calculating, for each of the thermal chambers, a heat flux differential by comparing the heat flux values calculated during a first operating period to heat flux values calculated during a second operating period; and

updating one or more error correction coefficients of the thermal model based on the heat flux differentials.

7 . The vehicle battery protection device of claim 6 , wherein the thermal analysis calibration further includes

flagging the switch temperature sensor, the processor temperature sensor, or the ambient temperature sensor if the flagged temperature sensor produces data outside of

a rated range for the flagged temperature sensor; or

a computed operating range for the flagged temperature sensor, the computed operating range being dependent upon the concurrent temperature data of one or more non-flagged temperature sensors.

8 . The vehicle battery protection device of claim 7 , wherein the thermal analysis calibration further includes

disabling the vehicle battery protection device if the switch temperature sensor is flagged;

disregarding measured processor temperature if the processor temperature sensor is flagged; and

disregarding measured ambient temperature if the ambient temperature sensor is flagged.

9 . The vehicle battery protection device of claim 6 , wherein at least one thermal insulation member is disposed between the first thermal chamber and the second thermal chamber.

10 . The vehicle battery protection device of claim 6 , wherein the thermal safety algorithm further comprises a vehicle profiling process including:

generating a time series database, the time series database including sensor measurements from a plurality of sensors during an implementation time interval;

referencing state sensor parameters corresponding to a plurality of distinct vehicle state event types;

identifying vehicle state events by comparing the time series database to the state sensor parameters, each vehicle state event being defined by an occurrence of one of the vehicle state event types;

recording the vehicle state events in an event history dataset;

detecting, from the event history dataset, occurrences of event patterns, each event pattern being defined by a distinct combination of a fixed number of sequential vehicle state event types; and

generating an event pattern database including, for each event pattern detected within the event history dataset, an event pattern dataset including

number of occurrences of the event pattern; and

relative probabilities for each of the vehicle state event types to occur immediately after the event pattern.

11 . The vehicle battery protection device of claim 10 , wherein the vehicle profiling process further includes

establishing a confidence level for each event pattern, the confidence level being based on number of occurrences of the respective event pattern.

12 . The vehicle battery protection device of claim 11 , wherein the vehicle profiling process further includes

generating an event type statistics database including, for each of the vehicle state event types occurring in the event history dataset, an event type statistics dataset comprising

average duration of the vehicle state event type;

average switch current; and

maximum switch current.

13 . The vehicle battery protection device of claim 12 , wherein the vehicle profiling process further includes

determining a present event pattern, the present event pattern being defined by a combination of a present vehicle state event type and two or more sequentially preceding vehicle state event types, the sequentially preceding vehicle state event types being defined as a sequence of vehicle state event types which occurred immediately prior to the present vehicle state event type;

referencing the event pattern dataset corresponding to the present event pattern; and

identifying predicted next state event types, the predicted next state event types being defined by state event types in the referenced event pattern dataset having a non-zero probability of occurring immediately after the present event pattern.

14 . The vehicle battery protection device of claim 13 , wherein the thermal safety algorithm comprises a thermal loads prediction process including

referencing the event type statistics datasets corresponding to each of the predicted next state event types; and

generating a thermal loads prediction database based on the referenced event type statistics datasets and the thermal model, the thermal loads prediction database including, for each of the thermal chambers, a predicted thermal load corresponding to each of the predicted next state event types.

15 . The vehicle battery protection device of claim 14 , wherein the thermal safety algorithm comprises a composite risk analysis including

generating, for the first thermal chamber, a first baseline thermal risk score defined by a ratio of the switch temperature to a first chamber temperature safety threshold;

generating, for the first thermal chamber, a first thermal risk dataset comprising for each of the predicted next state event types,

(i) a thermal risk prediction defined by a ratio of the sum of the switch temperature and the predicted thermal load to the first chamber temperature safety threshold;

(ii) the probability of the state event type occurring immediately after the present event pattern; and

(iii) a thermal trend prediction defined by the difference between the thermal risk prediction and the first baseline thermal risk score;

setting, for the first thermal chamber, a first composite risk score based on

(i) the first thermal risk dataset; and

(ii) the confidence level corresponding to the present event pattern; and

generating, for the first thermal chamber, a first composite thermal trend defined by the difference between the first composite risk score and the first baseline thermal risk score.

16 . The vehicle battery protection device of claim 15 , wherein the composite risk analysis further includes

generating, for the second thermal chamber, a second baseline thermal risk score defined by a ratio of the processor temperature to a second chamber temperature safety threshold;

generating, for the second thermal chamber, a second thermal risk dataset comprising for each of the predicted next state event types,

(i) a thermal risk prediction defined by a ratio of the sum of the processor temperature and the predicted thermal load to second chamber temperature safety threshold;

(ii) the probability of the state event type occurring immediately after the present event pattern; and

(iii) a thermal trend prediction defined by the difference between the thermal risk prediction and the second baseline thermal risk score;

setting, for the second thermal chamber, a second composite risk score based on

(i) the second thermal risk dataset; and

(ii) the confidence level corresponding to the present event pattern; and

generating, for the second thermal chamber, a second composite thermal trend defined by the difference between the second composite risk score and the second baseline thermal risk score.

17 . The vehicle battery protection device of claim 16 , wherein

confidence levels for the event patterns are divisible into at least a level one, a level two, a level three and a level four, the level one being the lowest confidence level and the level four being the highest confidence level; and

in setting the first composite risk score,

if the confidence level of the present event pattern is a level one, the first composite risk score is equivalent to the highest thermal risk prediction of all of the predicted next state event types in the first thermal risk dataset;

if the confidence level of the present event pattern is a level two, the first composite risk score is the average of the two highest thermal risk predictions of all of the predicted next state event types in the first thermal risk dataset;

if the confidence level of the present event pattern is a level three, the first composite risk score is the average of the two thermal risk predictions of the predicted next state event types having the two highest probabilities of occurring immediately after the present event pattern in the first thermal risk dataset; and

if the confidence level of the present event pattern is a level four, the first composite risk score is equivalent to the thermal risk prediction of the predicted next state event type having the highest probability of occurring immediately after the present event pattern in the first thermal risk dataset.

18 . The vehicle battery protection device of claim 17 , wherein

in setting the second composite risk score,

if the confidence level of the present event pattern is a level one, the second composite risk score is equivalent to the highest thermal risk prediction of all of the predicted next state event types in the second thermal risk dataset;

if the confidence level of the present event pattern is a level two, the second composite risk score is the average of the two highest thermal risk predictions of all of the predicted next state event types in the second thermal risk dataset;

if the confidence level of the present event pattern is a level three, the second composite risk score is the average of the two thermal risk predictions of the predicted next state event types having the two highest probabilities of occurring immediately after the present event pattern in the second thermal risk dataset; and

if the confidence level of the present event pattern is a level four, the second composite risk score is equivalent to the thermal risk prediction of the predicted next state event type having the highest probability of occurring immediately after the present event pattern in the second thermal risk dataset.

19 . The vehicle battery protection device of claim 16 further comprising one or more activatable thermal devices, wherein the thermal safety algorithm comprises

limiting activation of at least one of the one or more activatable thermal devices in the first thermal chamber based on the first chamber composite risk score and the first chamber composite thermal trend.

20 . The vehicle battery protection device of claim 19 , wherein the thermal safety algorithm comprises selecting a mitigation strategy including

selecting between a baseline mitigation setting and a proactive mitigation setting based upon the state of charge of the vehicle battery and present measured ambient temperature;

applying a baseline set of thermal activation thresholds to the activation limiting when the baseline mitigation setting is selected; and

applying a proactive set of thermal activation thresholds to the activation limiting when the proactive mitigation setting is selected.

21 . The vehicle battery protection device of claim 19 , wherein the one or more activatable thermal devices are selected from the group consisting of a Peltier module, a cooling fan, a microelectromechanical-system cooler, and a resistive heater.

22 . The vehicle battery protection device of claim 16 , wherein the thermal safety algorithm comprises

allowing or preventing a deep sleep state in at least one of the one or more processors based on

(a) the first chamber composite risk score and the first chamber composite thermal trend; or

(b) the second chamber composite risk score and the second chamber composite thermal trend.

23 . The vehicle battery protection device of claim 16 , wherein the thermal safety algorithm comprises

enabling or disabling the solid state switch based on

(a) the first chamber composite risk score and the first chamber composite thermal trend; or

(b) the second chamber composite risk score and the second chamber composite thermal trend.

24 . The vehicle battery protection device of claim 16 further comprising a user interface.

25 . The vehicle battery protection device of claim 24 , wherein the thermal safety algorithm comprises

displaying one or more thermal warning indications on the user interface based on

(a) the first chamber composite risk score and the first chamber composite thermal trend; or

(b) the second chamber composite risk score and the second chamber composite thermal trend.

26 . The vehicle battery protection device of claim 25 , wherein at least one of the one or more thermal warning indications are selected from the group consisting of hot, warm and cold.

27 . The vehicle battery protection device of claim 24 , wherein the user interface includes a display screen or illuminable indicators.

28 . The vehicle battery protection device of claim 24 , wherein the user interface includes a buzzer, a speaker or a vibration motor.

29 . The vehicle battery protection device of claim 24 , wherein the user interface includes a user-activatable touch-sensitive device or a button.

30 . The vehicle battery protection device of claim 24 , wherein the user interface includes a wired or wireless remote control to inform or interact with the user.

31 . The vehicle battery protection device of claim 24 , wherein the user interface includes a local or remote sensor configured to receive a near field communication carrier frequency to interact and share data with the user.

32 . The vehicle battery protection device of claim 24 , wherein the user interface includes a local or remote sensor configured to receive a near field communication carrier frequency to allow the user to enable or disable the vehicle battery protection device.

33 . The vehicle battery protection device of claim 32 , wherein

the local or remote sensor can read a unique number and save this number into memory; and

at least one of the one or more processors is configured to treat the unique number as a key for interactive control of the vehicle battery protection device by a user.

34 . The vehicle battery protection device of claim 10 , wherein the implementation time interval is defined as being within the time the vehicle battery protection device is electrically connected between the vehicle battery and the vehicle electrical system.