Method for identifying a cell thermal dissipation of a power battery of a motor vehicle, battery warning

Abstract

The invention relates to a battery alarm system (12) and to a method for detecting a thermal diffusion of at least one battery cell (16) of a power battery (14) of a motor vehicle (10). In the method, temperature values of the battery cells (16) are determined (S10) by means of a temperature sensor (20) of the cell management controller CMC (18), whether at least one of the determined temperature values fulfills a predefined thermal diffusion condition is determined (S12) by means of an evaluation unit (22) of the cell management controller CMC (18), and if the predefined thermal diffusion condition is not fulfilled, the temperature values of the battery cells (16) are determined (S10) by means of a temperature sensor (20) of the cell management controller CMC (18). If the predetermined thermal diffusion condition is satisfied, the determined temperature value is transmitted (S14) to the battery management controller BMC (24) at a predetermined transmission time interval, and if the predetermined thermal diffusion condition is satisfied, a diffusion alarm signal is transmitted (S16) to the battery management controller BMC (24) via the cell management controller CMC (18).

Description

technical field [0001] The invention relates to a method and a battery warning system for detecting the heat dissipation of at least one battery cell of a traction battery of a motor vehicle, and to a motor vehicle with the battery warning system. Background technique [0002] In rare cases, thermal runaway / thermal runaway (Thermal Runaway) may occur in the battery cell of the power battery. In such a thermal runaway situation, one or more battery cells can be heated violently due to an exothermic chemical reaction, which can lead to a fire and a large increase in pressure due to combustion gases. As a result, in particular one or more further battery cells are affected and thermal runaway occurs, which is referred to as thermal spread. In order to warn the driver and / or the manufacturer when such thermal spread occurs, attempts are currently being made to identify thermal spread in the battery management controller (BMC) by means of temperature thresholds and temperature g...

AI Technical Summary

Problems solved by technology

[0003] Due to the limited bandwidth of the bus system used and the predefined transmission time intervals, the measured temperature values ​​cannot be transmitted between the CMC and BMC in real time nor in a technically feasible value range

[0004] It can thus happen that the temperature sensor itself is damaged between two transmissions of the temperature value due to thermal runaway of one or more battery cells, which can take place within 100 ms to 500 ms, and is therefore damaged by both the BMC and the BMC. It is not possible to determine temperature gradients nor excessive cell temperatures, since the CMC is only able to send error values

Also, the BMC cannot determine whether sensor failure or thermal runaway or thermal spread is causing the erroneous value of the sensor signal

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