Battery control system and vehicle control system

1. A battery control system connected to a battery, which controls charge/discharge at the battery, comprising:

a memory configured to store data;

a processor in communication with the memory and configured to:

record a plurality of temperature values acquired at the battery over time;

determine if a first period of time has elapsed since: a start of charge/discharge at the battery; or

a recording of each of the plurality of temperature values acquired at the battery;

when the first period of time is determined to elapse;

obtain a plurality of current values measured over a second period of time,

each measured current value corresponding to charge/discharge current flowing through the battery for a plurality sampling intervals;

obtain one of the plurality of current values measured for a previous sampling interval;

calculate an effective current value as a square root of a mean square value of the plurality of current values;

determine if the effective current value is greater than a predetermined current value;

if the effective current value is determined to be greater than the predetermined current value, and

restrict the charge/discharge current flowing through the battery in a low-temperature state based upon the recorded plurality of temperature values acquired at the battery.

2. The battery control system according to claim 1 , wherein the processor is further configured to:

determine whether to restrict the charge/discharge current based upon the plurality of temperature values, a highest temperature at the battery as the battery is charged/discharged continuously or intermittently over a period of time equal to or greater than a predetermined continuous time period;

and compare the highest temperature with a predetermined threshold value.

3. The battery control system according to claim 2 , wherein:

the continuous time period is set in correspondence to a period of time to elapse until the temperature at the battery enters a state of equilibrium during charge/discharge.

4. The battery control system according to claim 2 , wherein:

a plurality of varying time periods are set in correspondence to the continuous time period; and

the predetermined threshold value takes a greater value in correspondence to the continuous time period as the continuous time period increases.

5. The battery control system according to claim 2 , wherein:

a first threshold value and a second threshold value lower than the first threshold value are set to be used as the threshold value; and

the processor is further configured to:

impose a first charge/discharge restriction so as to restrict the charge/discharge current if the highest temperature is lower than the first threshold value and impose a second charge/discharge restriction so as to further restrict the charge/discharge current if the highest temperature is lower than the second threshold value.

6. The battery control system according to claim 5 , wherein:

the processor is further configured to:

having impose the first charge/discharge restriction, clears the first charge/discharge restriction when the highest temperature subsequently exceeds the first threshold value, and

having imposed the second charge/discharge restriction, sustain the second charge/discharge restriction even if the highest temperature subsequently exceeds the second threshold value.

7. The battery control system according to claim 6 , wherein:

the processor is further configured to:

clear the second charge/discharge restriction when a length period of elapsed time having elapsed since the second charge/discharge restriction came into effect or a total period of time over which the second charge/discharge restriction has been in effect exceeds a predetermined restriction clearance time.

8. The battery control system according to claim 7 , wherein:

the battery control system is connected to an in-vehicle communication network; and

the charge/discharge restriction unit obtains information pertaining to the period of elapsed time or the total period of time via the communication network.

9. The battery control system according to claim 1 , wherein if the effective current value is determined to not be greater than the predetermined current value, do not restrict the charge/discharge current flowing through the battery.

10. The battery control system according to claim 1 , wherein the processor is further configured to:

record the plurality of temperature values during the charge/discharge at the battery; and

delete the plurality of temperature values when the charge/discharge stops.