Method and device for detecting internal temperature of battery

Abstract

The invention provides a method and a device for detecting the internal temperature of a battery. The method comprises steps: an AC impedance spectroscopy of the battery is acquired; according to the AC impedance spectroscopy of the battery, a characteristic frequency range is determined, and an impedance parameter in a monotony relationship with the temperature is selected from the characteristic frequency range; and according to the impedance parameter in a monotony relationship with the temperature and the corresponding relationship between the impedance parameter and the temperature, a battery internal temperature detection model is built, and thus, the battery internal temperature is obtained. According to the method and the device for detecting the internal temperature of the battery, the impedance characteristic parameter of the battery and the internal temperature of the battery are integrated, the internal temperature of the battery is detected on the premise of not damaging the battery structure, and the feasibility and the practicability are high.

Description

technical field [0001] The invention relates to a battery temperature detection technology, in particular to a battery internal temperature detection method and device. Background technique [0002] Since its inception, batteries have been favored by governments and researchers all over the world for their superior performance such as high energy density, long service life, and environmental protection, and have been widely used in the electric vehicle industry and energy storage fields. [0003] Lifespan and safety have always been the two most important problems restricting the development of battery technology. During the use of the battery, with the increase in the number of cycles, the positive and negative active electrode materials of the battery gradually age, and the electrolyte gradually decomposes, resulting in capacity attenuation, internal resistance, and service life. At the same time, the increase of the internal resistance of the battery will increase the he...

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Problems solved by technology

[0006] One of the most important means in the battery thermal model simulation and thermal management system is to detect and monitor the internal ambient temperature of the battery. Currently, it is difficult to directly measure the internal ambient temperature of the battery, and the surface temperature of the battery is usually used as an approximate replacement. , but the battery is not a good conductor of heat. Only grasping the temperature distribution of the battery surface cannot fully explain the thermal state inside the battery. It is necessary to calculate the temperature inside the battery through a mathematical model and predict the thermal behavior of the battery. This is not possible when designing a battery pack thermal management system. missing link

[0007] During the actual use of the battery, the battery structure must maintain integrity and cannot be disassembled, so it is impossible to directly measure the internal ambient temperature of the battery. The current test method for the internal temperature of the battery is to measure the temperature of the external surface of the battery.

Most of the heat generated by the battery comes from the internal reaction of the battery, which exchanges heat with the outside through heat transfer. However, the battery itself is not a good conductor of heat and cannot guarantee the uniformity of heat transfer. Therefore, the internal temperature of the battery is often higher than that of the battery. The external surface temperature of the battery, and the approximate replacement of the internal temperature by the external surface temperature of the battery is obviously not accurate

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