GaryG
09-22-2006, 08:17 PM
Hi Folks
To better understand the automatic battery conditioning system in the FEH, here is something I put together with the help of the Ford patent on this issue. There have been many post regarding strange behavior while driving the FEH, and many times it's normal and caused by the battery conditioning system.
The TBCM (Traction Battery Control Module), controls charging and/or discharging of an HEV battery, in response to battery life and/or performance degrading events, or battery maintenance conditions. The TBCM monitors for four battery life and/or performance degrading events.
First, the TBCM determines if the battery needs to be charged to reverse deactivation. Deactivation is caused by prolonged duration of idle time at low state of charge (SOC). Deactivation results in reduced ability to accept charge.
Second, the TBCM determines if the battery needs to be refreshed to reverse memory effect. Memory effect is caused by repeated shallow discharging and recharging, or cycling, of the battery. Memory effect causes a loss of storage capacity.
Third, the TBCM determines if the battery needs rebalancing. The typical HEV battery, like the battery, is constructed from cells or modules that are coupled together to provide the desired voltage. A typical HEV battery may have as many as 240 modules. The modules of the battery will have different performance characteristics based on manufacturing differences, module age and module temperature, for example. If a module that has diminished charge capacity is overcharged, this can lead to module failure.
Fourth, the TBCM determines if the battery needs state of charge reset. A module can be so deeply discharged that the battery reverses. This reversal can adversely affects battery performance, and can cause long-term damage to the module and the circuitry coupled thereto.
While the TBCM monitors the battery for these four battery maintenance conditions, it is not so limited. The TBCM may monitor the battery for other battery life and/or performance degrading events other than those listed above.
Having determined that one of these four conditions exists, the TBCM communicates with the VSC via CAN to determine if the necessary remedial activity can be conducted immediately, or if the activity needs to be delayed to avoid interference with vehicle operations. For example, to refresh the battery to remove memory effect, it may be desirable to deeply discharge and then charge the affected module. It may also be the case that the vehicle is operating in a state or mode where the battery is already in a state of discharge, or the capacity is not available to charge the module. Alternatively, it may be the case that the TBCM, to determine the state of the battery, needs to perform a diagnostic discharge or charge of the module of the battery , which diagnostic discharge or charge may affect vehicle performance. Consequently, the TBCM preferably first determines if the diagnostic or remedial action would compromise the vehicle's performance by communicating with the VSC and determining a vehicle condition.
http://www.freepatentsonline.com/6686724.html
GaryG
To better understand the automatic battery conditioning system in the FEH, here is something I put together with the help of the Ford patent on this issue. There have been many post regarding strange behavior while driving the FEH, and many times it's normal and caused by the battery conditioning system.
The TBCM (Traction Battery Control Module), controls charging and/or discharging of an HEV battery, in response to battery life and/or performance degrading events, or battery maintenance conditions. The TBCM monitors for four battery life and/or performance degrading events.
First, the TBCM determines if the battery needs to be charged to reverse deactivation. Deactivation is caused by prolonged duration of idle time at low state of charge (SOC). Deactivation results in reduced ability to accept charge.
Second, the TBCM determines if the battery needs to be refreshed to reverse memory effect. Memory effect is caused by repeated shallow discharging and recharging, or cycling, of the battery. Memory effect causes a loss of storage capacity.
Third, the TBCM determines if the battery needs rebalancing. The typical HEV battery, like the battery, is constructed from cells or modules that are coupled together to provide the desired voltage. A typical HEV battery may have as many as 240 modules. The modules of the battery will have different performance characteristics based on manufacturing differences, module age and module temperature, for example. If a module that has diminished charge capacity is overcharged, this can lead to module failure.
Fourth, the TBCM determines if the battery needs state of charge reset. A module can be so deeply discharged that the battery reverses. This reversal can adversely affects battery performance, and can cause long-term damage to the module and the circuitry coupled thereto.
While the TBCM monitors the battery for these four battery maintenance conditions, it is not so limited. The TBCM may monitor the battery for other battery life and/or performance degrading events other than those listed above.
Having determined that one of these four conditions exists, the TBCM communicates with the VSC via CAN to determine if the necessary remedial activity can be conducted immediately, or if the activity needs to be delayed to avoid interference with vehicle operations. For example, to refresh the battery to remove memory effect, it may be desirable to deeply discharge and then charge the affected module. It may also be the case that the vehicle is operating in a state or mode where the battery is already in a state of discharge, or the capacity is not available to charge the module. Alternatively, it may be the case that the TBCM, to determine the state of the battery, needs to perform a diagnostic discharge or charge of the module of the battery , which diagnostic discharge or charge may affect vehicle performance. Consequently, the TBCM preferably first determines if the diagnostic or remedial action would compromise the vehicle's performance by communicating with the VSC and determining a vehicle condition.
http://www.freepatentsonline.com/6686724.html
GaryG