Precise knowledge of the battery heat generation rate and the internal temperature rise allows accurate thermal regulation required for enabling fast charging while minimizing side reactions and avoiding thermal runaway. With the necessity of high energy density, the size of batteries is constantly increasing. Because of poor thermal conduction, the thermal lag in large batteries is significant resulting in a considerable temperature gradient within the cell. Existing calorimetry methods only account for the external heat flow measurement and the external temperature rise and therefore cannot account for the thermal lag inside the cell. Additionally, with these methods, the temporal (time-resolved) information of the heat generation rate is compromised, which makes observation and attribution of electrochemical- thermal signatures impossible. As a potential solution, various intrusive techniques such as embedded thermal sensors have been proposed in the literature. However, these techniques are limited in scope. To enable accurate measurement of time-resolved heat flux measurement in commercial batteries, we instead propose a new battery calorimetry approach by combining state-of-the-art commercial calorimetry with an inverse heat transfer algorithm. This inverse calorimetry is completely non-intrusive with no change to commercial calorimeters. The inverse calorimetry reduces the error in heat generation rate to within 10% of the actual heat generation rate compared to 50% from the lumped capacitance method (best existing method). This method enables time resolved observation of electrochemical-thermal signatures such as a negative heat generation rate due to entropy change, which could not be observed from existing calorimetry methods.

准确了解电池发热率和内部温升可以实现快速充电所需的精确热调节，同时最大限度地减少副反应并避免热失控。随着高能量密度的需要，电池的尺寸不断增大。由于热传导不良，大型电池中的热滞后现象很明显，导致电池内出现相当大的温度梯度。现有的量热法仅考虑外部热流测量和外部温升，因此无法考虑电池内部的热滞后。此外，使用这些方法，热生成率的时间（时间分辨）信息受到损害，这使得电化学-热特征的观察和归因变得不可能。作为一种潜在的解决方案，文献中提出了各种侵入式技术，例如嵌入式热传感器。然而，这些技术在范围上是有限的。为了能够准确测量商用电池中的时间分辨热通量测量，我们提出了一种新的电池量热法，将最先进的商用量热法与逆热传递算法相结合。这种逆量热法是完全非侵入式的，对商用量热仪没有任何改变。与集总电容法（现有最佳方法）的 50% 相比，逆量热法将发热率的误差降低到实际发热率的 10% 以内。这种方法能够对电化学-热特征进行时间分辨观察，例如熵变引起的负热生成率，