ELECTRIC VEHICLE BATTERY PACK VOLTAGE MONITORING
First Claim
1. An electric vehicle system, comprising:
- a multi-cell battery pack providing a main battery voltage between a positive bus and a negative bus;
a main microcontroller monitoring performance of the battery pack, the main microcontroller being coupled to a chassis ground and being digitally isolated from the positive and negative busses;
a battery monitoring IC connected to the battery pack to measure respective voltages of cells in the battery pack, wherein the battery monitoring IC has an isolated serial data link to the main microcontroller to report the measured voltages, and wherein the battery monitoring IC further includes a plurality of auxiliary/thermistor A/D inputs and an auxiliary output terminal selectably providing a drive signal;
an evaluation switch having an input, an output, and a control terminal, wherein the input is connected to the positive bus, and wherein the control terminal is coupled to the auxiliary output terminal so that the evaluation switch is activated in response to a command received from the main microprocessor over the serial data link; and
a voltage divider coupled between the output of the evaluation switch and the negative bus and providing a divided voltage output to one of the auxiliary/thermistor A/D inputs;
wherein the battery monitoring IC transmits a digital value representative of the divided voltage output to the main microprocessor via the serial data link, and wherein the main microprocessor determines the main battery voltage in response to the digital value.
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Accused Products
Abstract
Total voltage output by a multi-cell battery pack in an electric vehicle is monitored. A main microcontroller having a chassis ground is digitally isolated from positive and negative busses of the battery pack. A battery monitoring IC having a plurality of auxiliary/thermistor A/D inputs measures respective voltages of the battery cells. A voltage divider is selectably coupled to the positive bus by an evaluation switch under control of the main microprocessor with an auxiliary output terminal of the IC. A divided voltage is coupled to one of the auxiliary/thermistor A/D inputs. The battery monitoring IC transmits a digital value representative of the divided voltage output to the main microprocessor via the serial data link, and the main microprocessor determines the main battery voltage in response to the digital value.
13 Citations
5 Claims
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1. An electric vehicle system, comprising:
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a multi-cell battery pack providing a main battery voltage between a positive bus and a negative bus; a main microcontroller monitoring performance of the battery pack, the main microcontroller being coupled to a chassis ground and being digitally isolated from the positive and negative busses; a battery monitoring IC connected to the battery pack to measure respective voltages of cells in the battery pack, wherein the battery monitoring IC has an isolated serial data link to the main microcontroller to report the measured voltages, and wherein the battery monitoring IC further includes a plurality of auxiliary/thermistor A/D inputs and an auxiliary output terminal selectably providing a drive signal; an evaluation switch having an input, an output, and a control terminal, wherein the input is connected to the positive bus, and wherein the control terminal is coupled to the auxiliary output terminal so that the evaluation switch is activated in response to a command received from the main microprocessor over the serial data link; and a voltage divider coupled between the output of the evaluation switch and the negative bus and providing a divided voltage output to one of the auxiliary/thermistor A/D inputs; wherein the battery monitoring IC transmits a digital value representative of the divided voltage output to the main microprocessor via the serial data link, and wherein the main microprocessor determines the main battery voltage in response to the digital value. - View Dependent Claims (2, 3, 4)
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5. An electric-vehicle battery monitoring method comprising:
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digitally isolating a main microprocessor from a battery monitoring IC; selectably coupling a voltage divider between a positive bus and a negative bus driven by a multi-cell battery pack; digitally sampling a divided voltage using an auxiliary/thermistor input of the IC; transmitting a digital sample to the main microprocessor via an isolated serial data link; evaluating the digital sample to determine an output voltage of the battery pack.
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Specification