随着车辆电气化的进展，工程师必须小心以最大程度地发挥电池寿命，同时确保最高水平的功能安全性。电池监控应用特定的集成电路（ASIC）可以帮助实现这两个目标，实施自动宿主反向磁力功能，监视电池电压和温度，并提供自主细胞平衡。
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- Conserve battery power in HEV/EVs with industry's first patented automatic host reverse wakeup
- 电池电气化电池管理中的功能安全考虑因素
- Enhance thermal management in EVs with autonomous cell balancing
功能安全
电动车安全考虑因素是多方面的。它们包括保护生产工人，所有者，力学和回收商免受高压；保护电池电池免受穿刺和撞击损伤；并保持电气系统的完整性，以确保细胞在安全温度和电压范围内运行。
最后考虑是特别重要的。在可接受的电压和温度范围之外，电池内可能会发生不良反应，这可能导致过度自热，内部电短短裤，并最终导致热失控。为了避免这些问题，电池监控ASIC测量并将有关电压和温度的信息传输到电池管理单元（BMU）。
电池管理功能面临着自己的挑战。电动乘用车可能具有128个或更多的电池。商用车可能具有两倍的数字。大型电池系统具有许多可能发生故障的印刷电路板（PCB）连接：例如，在ASIC之间的通信链接中打开，或者在ASIC之间打开。如ISO 26262公路车辆标准所述，检测和解决此类故障以避免危险事件是功能安全性的一部分。
In some automotive systems, the safe response to a loss of functionality is simply to switch off the electronics and notify the driver through a dashboard indicator. In other cases, however, simply switching off the electronics may not be safe, and design goals may include a “safety-related availability” requirement in which the system must have a tolerance—perhaps achieved through redundancy—for some types of faults for a period of time to avoid hazardous events.
电池监控子系统提供了冗余如何工作的示例。在这样的子系统中，ASIC以堆叠构型排列，每个测量电压和多个单元的温度。测量数据流从ASIC到ASIC以及微控制器单元（MCU），该单元（MCU）计算电池状态，并有助于确保该操作保持在安全范围内。在传感或通信路径中打开或短裤可能会将子系统“盲目”到潜在的故障上，可能导致危险事件。
Texas Instruments的BQ79606A-Q1和BQ79616-Q1电池监控ASIC家族包括为这些类型的故障提供容忍度的功能，从而使系统能够继续监视电池包的健康和安全性。
图1说明双向环配置中的BQ79616-Q1设备。如果在两个电池监控ASIC之间进行开放，MCU继续通过BQ79600-Q1 SPI/UART通信界面与ASIC进行通信，从而根据需要切换消息传递的方向。尽管在故障期间禁用了正常的通信，但该系统可以使用双向环通信功能的容错保持可用性，而电池模块中没有电压和温度信息的损失。
Further supporting redundancy, the BQ79606A-Q1 and BQ79616-Q1 also feature dual analog-to-digital converters (ADCs). In a system without redundancy, a single ADC monitors the voltage sensing signal (VC). With the dual ADCs of the BQ79606A-Q1 and BQ79616-Q1, a second ADC monitors the cell-balance signal (CB), thereby allowing the system to continue monitoring voltage even if an open occurs in the VC path(Fig. 2)。
Automatic Wakeup
典型的电动或混合动力汽车包括由12V电池供电的BMU。要在停放车辆时查找高压（HV）电池组中的故障，BMU的MCU定期醒来，可能会过早放电12-V电池。
另一种是automatic host-reverse-wakeup implementation that wakes up the MCU only on detection of a fault。The BQ79616-Q1, which incorporates a patented wake-up-at-fault feature, can serve at the heart of such an implementation. The BQ79616-Q1 offers a low-power sleep mode during which it can still monitor overtemperature and undertemperature, as well as overvoltage and undervoltage, fault conditions. On detecting a fault in sleep mode, the device is able to transmit the fault status through a fault tone.
如图所示图3, a series of BQ79616-Q1 devices monitor the HV batteries. On detecting a fault, a BQ79616-Q1 transfers, via a ring architecture, the fault tone to a BQ79600-Q1 communication interface located on the BMU. The BQ79600-Q1 then enables the BMU’s power-management IC (PMIC), which in turn wakes up the MCU. The result is conservation of 12-V battery power while supporting functional safety requirements while the vehicle is parked or turned off.
Cell Balancing
细胞平衡可以纠正车辆电池中的失衡，并有助于扩展车辆驾驶范围，同时确保安全操作。You can choose one of two approaches. Active cell balancing employs dc-dc converters to redistribute energy from a cell with a high level of charge to one with a lower level. Passive balancing removes charge from cells with more charge, typically through thermal dissipation, until all cells have the same amount of charge. Passive balancing is a more popular approach given its simplicity and lower cost.
TI的BQ79616-Q1使用连接到外部平衡电阻的内部开关执行被动细胞平衡。设备和电阻器中的两个开关都是过热的潜在来源，BQ79616-Q1通过两个热管理功能来解决。
首先，高温温度会触发MCU的故障，MCU会停止平衡直到死亡温度下降并清除任何故障。第二个，BQ79616-Q1监视电路板安装的热敏电阻，并自动停止平衡，如果温度超过预设阈值。当温度下降到可接受的水平时，平衡恢复 - 所有人都没有MCU干预。
结论
TI’s battery monitors and balancers perform a variety of functions in electric vehicles, from wake-up-on-fault operation to cell balancing. They offer thermal-management features and implement fault-tolerant temperature and voltage measurement, providing systematic functional safety capability up to Automotive Safety Integrity Level (ASIL) D.
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