Network restart from power saving mode in WBMS

Abstract

In one example, a wireless battery management system (200) includes one or more sets of battery cells (208). The wireless battery management system includes a primary node (102) configured to broadcast a downlink packet in a first superframe and a first secondary node (206) coupled to the first set of battery cells. The first secondary node is configured to receive the downlink packet and transmit a first uplink packet to the primary node during the first superframe. The wireless battery management system includes a second secondary node (210) coupled to a second set of battery cells (212). The second secondary node is configured to receive a first uplink packet from the first secondary node in the first superframe and transmit a second uplink packet to the primary node during the second superframe.

Description

[Background technology]

[0001] Modern vehicles may contain multiple battery cells, and sensors may monitor information related to the battery cells, such as temperature, voltage, and other indicators of cell condition and health, to ensure safety and proper operation of the vehicle. Summary of the Invention

[0002] According to at least one example of the present description, a wireless battery management system includes one or more sets of battery cells. The wireless battery management system includes a primary node configured to broadcast a downlink packet in a first superframe. The wireless battery management system also includes a first secondary node coupled to the first set of battery cells. The first secondary node is configured to receive the downlink packet and transmit a first uplink packet to the primary node during the first superframe. The wireless battery management system includes a second secondary node coupled to a second set of battery cells. The second secondary node is configured to receive a first uplink packet from the first secondary node in the first superframe. The second secondary node is also configured to transmit a second uplink packet to the primary node during the second superframe.

[0003] In accordance with at least one example of the present description, a method includes transmitting a downlink packet from a primary node to one or more secondary nodes during a first superframe in a wireless battery management system. The method includes receiving the downlink packet at the first secondary node. The method also includes transmitting a first uplink packet from the first secondary node to the primary node during the first superframe. The method also includes receiving a first uplink packet at a second secondary node during the first superframe. The method includes transmitting a second uplink packet from the second secondary node to the primary node during a second superframe.

[0004] In accordance with at least one example of the present description, a method includes transmitting a first downlink packet from a primary node to one or more secondary nodes in a first superframe. The method also includes receiving the first downlink packet at the first secondary node in the first superframe. The method includes failing to receive the first downlink packet at a second secondary node in the first superframe. The method also includes transmitting a first uplink packet from the first secondary node to the primary node in the first superframe. The method includes transmitting a second downlink packet from the primary node to one or more secondary nodes in a second superframe. The method includes receiving the second downlink packet at the second secondary node in the second superframe. The method also includes transmitting a second uplink packet from the second secondary node to the primary node in the second superframe. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a block diagram of a wireless battery management system according to various examples.

[0006] [Figure 2] FIG. 1 is a block diagram of a wireless battery management system according to various examples.

[0007] [Figure 3A] 1 is a superframe interval that may be used by a wireless battery management system according to various examples.

[0008] [Figure 3B] 1 is a superframe interval that may be used by a wireless battery management system according to various examples.

[0009] [Figure 4A] 1 illustrates successive superframe intervals that may be used by a wireless battery management system according to various examples. [Figure 4B] 1 illustrates successive superframe intervals that may be used by a wireless battery management system according to various examples.

[0010] [Figure 5A] 1 is a graph of scaled power consumption for a secondary network node, in accordance with various examples.

[0011] [Figure 5B] 10 is a graph of scaled power consumption for a primary node, according to various examples.

[0012] [Figure 6] 1 is a table of approximate power consumption in a primary node and a secondary node according to various examples.

[0013] [Figure 7] 1 is a flowchart of a method for restarting a network from a power save mode, in accordance with various examples.

[0014] [Figure 8]1 is a flowchart of a method for restarting a network from a power save mode, in accordance with various examples herein.

[0015] In the drawings, the same reference numbers or other reference designators are used to denote the same or similar (functional and / or structural) features. DETAILED DESCRIPTION OF THE INVENTION

[0016] Some electronic devices operate using batteries. For example, an electric vehicle includes multiple battery cells that provide power to the vehicle. Because the battery cells in an electronic device can provide a large amount of power, and the power provided by the battery cells can be essential to the operation of the electronic device, the electronic device may include a system for managing the battery cells.

[0017] A battery management system (BMS) may manage the battery cells of an electronic device in various ways. For example, the BMS may monitor the health (e.g., voltage, current, temperature) of the battery cells in the electronic device. The BMS may also control the various battery cells to manage the amount of power provided by the battery cells and direct that power into the electronic device. Generally, a BMS includes multiple components, such as multiple battery modules and a controller for managing the battery modules. Each battery module may be connected to multiple battery cells and may include a battery monitor for monitoring the battery cells. Thus, the battery cells coupled to a battery module provide power to the electronic device, the battery monitor in the battery module monitors the health and operation of the battery cells in that battery module, and the controller communicates with the battery monitor to ensure that the battery module and its cells operate properly. The controller may also communicate with the battery monitor to control the operation of the battery cells, such as turning on, off, redirecting, or otherwise balancing the power provided by the battery cells.

[0018] A BMS may incorporate wireless technology to create a wireless battery management system (WBMS). For example, a primary network node may include or be coupled to a controller, and a secondary network node may include a battery module that controls multiple battery cells. The primary network node and the secondary network node may communicate with each other wirelessly, for example, using radio frequencies. In some protocols, a superframe is useful to facilitate wireless communication between the primary network node and the secondary network nodes. In a superframe, the primary network node first broadcasts a downlink (DL) communication (or packet) to multiple secondary network nodes. The secondary network nodes individually respond to the primary network node with an uplink (UL) communication (or packet) in a serial manner. Superframes are described further below.

[0019] A WBMS may have certain requirements for reliable operation, such as a certain throughput level, data rate, packet error rate, power consumption in each device (including the primary node), guarantees on how quickly sensors or monitors send data collected from battery cells, etc. Some example requirements may include a bandwidth of 600 kilobits per second (kbps), a data latency of less than 100 milliseconds (ms), a packet error rate of less than 10-5, and power consumption of less than 1 milliampere (mA) in the primary node and less than 300 microamperes (μA) in the secondary node.

[0020] Power consumption may be considered between two states: when the vehicle is on and when the vehicle is off. When the vehicle is on, the vehicle's battery or other high-voltage battery may power the wireless node. When the vehicle is off, the wireless node enters a low-power shutdown mode. However, in one example, after the vehicle is turned on again, the wireless node should start up and have the WBMS network running in less than 300 milliseconds, preferably as quickly as possible.

[0021] Wireless nodes in a WBMS network may communicate with each other using time intervals known as superframes. Superframes are divided into slots, which may be further allocated as downlink slots and uplink slots. Downlink slots transmit packets from primary nodes to secondary nodes. Uplink slots transmit packets from secondary nodes to primary nodes. In some examples, a primary node transmits a broadcast packet in a downlink slot, which is received by all secondary nodes.

[0022] When the vehicle is off and the WBMS is not active, a keep-alive approach may be useful in some instances. No activity occurs for several superframe intervals. Then, an active keep-alive superframe occurs, which may have a downlink and multiple uplinks. Following the active keep-alive superframe, one or more quiet superframes occur. After the quiet superframe, another active keep-alive superframe occurs, and the process is repeated as necessary. This approach saves power when the vehicle is off.

[0023] When a vehicle is turned off and then turned on, an interrupt is sent to the primary node. The interrupt may arrive in an idle superframe or an active superframe. If the primary node is active and can incorporate interrupt information into a downlink packet, it does so and sends that information to each secondary node (e.g., a wake-up signal). The secondary nodes may then respond. However, if the interrupt occurs during an idle superframe, the secondary nodes may not be active and may not listen. Instead, the secondary nodes may become idle and wait for the next active keep-alive superframe. In this scenario, the primary node waits for the next active superframe to send a wake-up signal. However, for various reasons, such as interference with wireless signals, the secondary nodes may not receive a downlink packet during the next active superframe. In this case, the WBMS must wait for another active superframe until all secondary nodes have woken up and responded. This scenario increases the time it takes to restart the network.

[0024] In an example herein, a first secondary node that fails to receive an expected downlink packet from a primary node during an active superframe may be configured to turn on its receiver and advantageously listen for other frames being transmitted to the primary node from other secondary nodes during the active superframe. When the first secondary node receives a transmission from another secondary node, the first secondary node wakes up and enters an active state. In another example herein, a first secondary node that misses a downlink packet from a primary node may be configured to listen during the next superframe with its receiver rather than listening during the current superframe. If there is any activity in the next superframe, WBMS becomes active and the first secondary node can continue normal operation.

[0025] FIG. 1 is a perspective view of an example system 100, such as a vehicle, that includes a WBMS 101. In some examples, the system 100 is any system that may include a wireless battery management system for powering one or more components of the system 100. As shown, the WBMS 101 includes a primary network node 102 (also referred to herein as a main node), a battery controller 104, multiple secondary network nodes 106, and multiple battery cells 108. In some examples, the WBMS 101 may include multiple primary network nodes. While this disclosure describes communication techniques primarily in the context of wireless systems, these techniques may also be useful in wired systems (e.g., where there is a wired connection between nodes 102 and 106). A primary network node is also referred to herein as a primary node, and a secondary network node is also referred to herein as a secondary node.

[0026] In some examples, the primary network node 102 is coupled to the battery controller 104 using a first wired connection 110. In some examples, the first wired connection 110 between the primary network node 102 and the battery controller 104 is a universal asynchronous receiver-transmitter (UART), an inter-integrated circuit (I2C), etc. The secondary network node 106 wirelessly couples to the primary network node 102 and couples to the battery cells 108 using a second wired connection 112.

[0027] In one example, the WBMS 101 provides wireless radio frequency (RF) communication between the primary network node 102 and the secondary network node 106. In one example, the wireless RF communication uses the license-free 2.4 gigahertz (GHz) Industrial, Scientific, and Medical (ISM) band from 2.4 GHz to 2.483 GHz in compliance with the BLUETOOTH Special Interest Group (STG). In some examples, the WBMS 101 uses 2 megabits per second (Mbps) BLUETOOTH Low Energy (BLE) over the physical layer (PHY). The Open Systems Interconnection (OSI) model includes the PHY as a layer used to communicate raw bits over a physical medium. In this case, the PHY is an open space that the WBMS 101 uses to communicate wirelessly between the primary network node 102 and the secondary network node 106. In one example, the transmit power of the WBMS 101 is 10 decibel milliwatts (dBm) or less. Additional exemplary details of establishing communication channels in a WBMS are described in commonly assigned U.S. patent application Ser. No. 17 / 233,106, filed April 16, 2021, entitled "Wireless Protocol for Battery Management," and U.S. patent application Ser. No. 17 / 399,793, filed August 11, 2021, entitled "Setting Up a Wireless Battery Management System," each of which is incorporated herein by reference in its entirety. [Patent Document 1] U.S. Patent Application No. 17 / 233,106 [Patent Document 2] U.S. Patent Application No. 17 / 399,793

[0028] In one example, wireless RF communications between the primary network node 102 and the secondary network node 106 utilize frequency hopping and time slot allocation to transmit and receive data over a superframe (SF). A superframe, also referred to as a superframe interval, is a time interval that includes time and frequency allocations for data exchange between the primary network node 102 and the secondary network node 106, as well as frame intervals between these allocations. Frequency hopping involves transmitting RF signals by rapidly changing the transmission frequency among multiple distinct frequencies occupying a spectral band. A time slot allocation is a time slot allocated to either the primary network node 102 or one or more secondary network nodes 106 for transmission to one or more secondary network nodes 106 or the primary network node 102. The time slot allocation is performed in half-duplex mode, with both the primary network node 102 and the secondary network node 106 switching between transmit and receive modes according to time instants identified in scan / pairing frames of data exchanged during the downlink / uplink duration. Additional example details of pairing are described in commonly assigned U.S. patent application Ser. No. 17 / 576,001, entitled "Operational Modes for Testing Monitor Circuits," filed Jan. 14, 2022, which is incorporated herein by reference in its entirety. [Patent Document 3] U.S. Patent Application No. 17 / 576,001

[0029] The WBMS 101 manages the battery cells 108 using a primary network node 102, a battery controller 104, and a secondary network node 106. The primary network node 102 and the secondary network node 106 communicate with each other about the status of the battery cells 108.

[0030] As mentioned above, a keep-alive process is useful when the vehicle is off. For a given keep-alive interval N, the keep-alive process skips (N-1) superframes, starts in the Nth superframe, processes any activity, and then goes dormant again. Various approaches may be useful for the keep-alive process. A first example is a fully active process. In this process, the primary network node turns on its receiver during the uplink portion of the Nth superframe, and the secondary network nodes send their responses to the primary network node. A second example is a partially active process. In this process, the primary network node turns off its receiver during the uplink portion of the Nth superframe, and the secondary network nodes are not required to send responses. Partially active superframes consume less power than fully active superframes. The keep-alive process may have any combination of idle, partially active, and fully active superframes.

[0031] FIG. 2 illustrates an example WBMS 200. The WBMS 200 is an example of the WBMS 101 described above. As shown, the WBMS 200 includes a primary network node 102, a battery controller 104, a memory 202, a processor 204, a first secondary network node 206, a first plurality or set of battery cells 208, a second secondary network node 210, and a second plurality or set of battery cells 212. Although not explicitly shown, additional secondary network nodes 206, 210 may be included. The primary network node 102 includes a memory 202 and a processor 204 configured to execute code 218 stored in the memory 202 to perform one or more operations attributed to the primary network node 102 herein. In one example, a portion of the memory 202 may be non-transitory and a portion of the memory 202 may be transitory. The secondary network nodes 206, 210 may also include a processor and memory. For example, as shown, the first secondary network node 206 includes a processor 220 coupled to a memory 222 that stores code 224, the code 224 being executable by the processor 220 to perform one or more operations attributed to the first secondary network node 206 herein.

[0032] The primary network node 102 is coupled to the battery controller 104 using a first wired connection 110 and is wirelessly coupled to each of the secondary network nodes 206, 210. The first secondary network node 206 is coupled to a first plurality or set of battery cells 208 using a third wired connection 214 and is wirelessly coupled to the primary network node 102. The second secondary network node 210 is coupled to a second plurality or set of battery cells 212 using a fourth wired connection 216 and is wirelessly coupled to the primary network node 102. Figure 2 does not limit the number of secondary network nodes in the WBMS 200; rather, the naming convention indicates that each of the secondary network nodes is coupled to multiple battery cells.

[0033] In some examples, the primary network node 102 is wirelessly coupled to at least eight secondary network nodes 206, 210. In some examples, each of the secondary network nodes 206, 210 may be coupled to at least 16 battery cells using wired connections. In some examples, the WBMS 200 includes one primary network node 102. In other examples, the WBMS 200 includes multiple primary network nodes 102.

[0034] The WBMS 200 manages a first plurality of battery cells 208 and a second plurality of battery cells 212 using a primary network node 102, a battery controller 104, a memory 202, a processor 204, a first secondary network node 206, and a second secondary network node 210. Instructions in the memory 202 cause the processor 204 to direct the primary network node 102 to wirelessly communicate with the first secondary network node 206 and the second secondary network node 210 about the status of the first plurality of battery cells 208 and the second plurality of battery cells 212. The primary network node 102 and the secondary network nodes 206, 210 may communicate using any suitable protocol format.

[0035] Either or both of processors 204 and 220 may include processing circuitry, such as one or more processors. Processors 204 and 220 may include any combination of integrated circuit elements, discrete logic circuit elements, and analog circuit elements, such as one or more microprocessors, microcontrollers, digital signal processors, application specific integrated circuits, central processing units, graphics processing units, field programmable gate arrays, and / or any other processing resources. In some examples, processors 204 and 220 may include multiple components, such as any combination of the processing resources listed above and other discrete or integrated logic circuit elements and / or analog circuit elements.

[0036] FIG. 3A is an example superframe interval 300 that may be used by a wireless battery management system, such as the WBMS 101. In FIG. 3A, each of the secondary network nodes 106 receives a downlink from the primary network node 102 and provides an appropriate response. FIG. 3B, described below, illustrates a situation in which a secondary network node (e.g., 206, 210, etc.) misses the downlink from the primary network node 102. Referring again to FIG. 3A, the term TsMaxRx refers to the maximum (Max) time (Ts) allotted to receive a packet (Rx), and the term TsMaxTx refers to the maximum (Max) time (Ts) allotted to transmit a packet (Tx). The primary network node 102 communicates with the first secondary network node 206, the second secondary network node 210, and the Nth secondary network node 301, for example, using the superframe interval 300. As shown, superframe interval 300 includes a DL transmit frame 302, a first UL receive frame 304, a second UL receive frame 306, a third UL receive frame 308, a DL guard frame 310, a DL transmit time frame 312, a first transmit-receive frame 314, a first UL receive time frame 316, a second transmit-receive frame 318, a second UL receive time frame 320, a third transmit-receive frame 322, a third UL receive time frame 324, a first DL receive frame 326, a first UL transmit frame 328, a first receive The frame includes a wait time 330, a first receive-to-transmit frame 332, a first UL transmit time frame 334, a second DL receive frame 336, a second UL transmit frame 338, a second receive wait time 340, a second receive-to-transmit frame 342, a second UL transmit time frame 344, a third DL receive frame 346, a third UL transmit frame 348, a third receive wait time 350, a third receive-to-transmit frame 352, a third UL transmit time frame 354, a first frame 356, a second frame 358, a third frame 360, and a fourth frame 362. Frames 356, 358, 360, and 362 may be referred to herein as slots 356, 358, 360, and 362, respectively.

[0037] The superframe interval 300 organizes communications between the primary network node 102 and the secondary network node 106 for wireless battery management. In one example, the superframe interval 300 is a medium access control (MAC) interval for data exchange between the primary network node 102 and the first secondary network node 206, the second secondary network node 210, and the Nth secondary network node 301. Each of the secondary network nodes 206, 210, 301 in the superframe interval 300 communicates with the primary network node 102 during a time slot, as discussed with reference to FIG.

[0038] In one example, the superframe interval 300 begins with a DL guard frame 310. The DL guard frame 310 is a period of time that ensures there is no interference between subsequent SFs. At the time of the DL guard frame 310, the first secondary network node 206 enters a first wait-for-receive period 330, the second secondary network node 210 enters a second wait-for-receive period 340, and the Nth secondary network node 301 enters a third wait-for-receive period 350.

[0039] In the first frame 356 of the superframe interval 300, after the DL guard frame 310, the primary network node 102 broadcasts a DL to all of the secondary network nodes 206, 210, 301 using a DL transmit frame 302 during a DL transmit time frame 312. The first secondary network node 206 receives the DL using a first DL receive frame 326, the second secondary network node 210 receives the DL using a second DL receive frame 336, and the Nth secondary network node 301 receives the DL using a third DL receive frame 346. After the DL transmit frame 302, the primary network node 102 enters a first transmit-receive frame 314 in preparation for receiving the UL from each of the secondary network nodes 206, 210, 301. At the same time that the primary network node 102 enters the first transmit-receive frame 314, the first secondary network node 206 enters the first receive-transmit frame 332 in preparation for transmitting a first UL to the primary network node 102.

[0040] In the second frame 358 of the superframe interval 300, the first secondary network node 206 transmits a first UL during the first UL transmit time frame 334 using the first UL transmit frame 328. The primary network node 102 receives the first UL during the first UL receive time frame 316 using the first UL receive frame 304. In the second frame 358, the primary network node 102 enters a second transmit-receive frame 318 in preparation for receiving a second UL from the second secondary network node 210. The second secondary network node 210 enters a second receive-transmit frame 342 in preparation for transmitting a second UL to the primary network node 102.

[0041] In the third frame 360 ​​of the superframe interval 300, the second secondary network node 210 transmits a second UL during the second UL transmit time frame 344 using the second UL transmit frame 338. The primary network node 102 receives the second UL during the second UL receive time frame 320 using the second UL receive frame 306. In the third frame 360, the primary network node 102 enters a third transmit-receive frame 322 in preparation for receiving a third UL from the Nth secondary network node 301. The Nth secondary network node 301 enters a third receive-transmit frame 352 in preparation for transmitting a third UL to the primary network node 102.

[0042] In the fourth frame 362 of the superframe interval 300, the Nth secondary network node 301 (e.g., the third secondary network node in one example) transmits a third UL during the third UL transmit time frame 354 using the third UL transmit frame 348. As shown in FIG. 3A, the fourth frame 362 is not necessarily contiguous with the third frame 360. The primary network node 102 receives the third UL during the third UL receive time frame 324 using the third UL receive frame 308. The schedule of frames 328, 338, and 348 shown in FIG. 3A may be referred to herein as the default uplink packet transmission schedule.

[0043] Figure 3A illustrates an example process by which each secondary node (e.g., 206, 210, 301) properly receives a DL from the primary network node 102 and responds with a UL. Figure 3B, described below, illustrates an example process that the WBMS may follow if at least one of the secondary nodes (e.g., 206, 210, 301) misses a DL from the primary network node 102 during its respective frame.

[0044] Figure 3B is another example superframe interval 300 that may be used by a wireless battery management system, such as the WBMS 101. In Figure 3B, a secondary network node (e.g., 206, 210, 301, etc.) misses a downlink from the primary network node 102. Figure 3B shows an example of an example secondary network node's response to missing the downlink from the primary network node 102. Figures 4A and 4B, described below, show another example of an example secondary network node's response to missing the downlink from the primary network node 102.

[0045] Many of the elements of Figure 3B are described above with respect to Figure 3A, with like numbers indicating like elements. Figure 3B also includes a fourth transmit-receive frame 368, a fourth UL receive time frame 370, a fourth UL receive frame 372, a fifth transmit-receive frame 374, a fifth UL receive time frame 376, and a fifth UL receive frame 378.

[0046] In one example, the first secondary network node 206 misses a DL transmission frame 302 from the primary network node 102. Figure 3B indicates this missed DL transmission frame with an "X" during the first wait-to-receive period 330. In this example, other secondary network nodes, such as the second secondary network node 210 and the Nth secondary network node N, successfully receive the DL transmission frame from the primary network node 102. However, in other examples, any number of secondary network nodes may miss the DL transmission frame and then perform the actions described in this example in response to missing the DL transmission frame.

[0047] The secondary network node 106 may miss a DL transmission frame from the primary network node 102 for various reasons, such as wireless interference (e.g., noise). In one example, the superframe interval 300 is a superframe that occurs one superframe after an idle superframe. That is, the superframe prior to the superframe interval 300 is a superframe in which the primary network node 102 and the secondary network node 106 are idle to conserve power. In the superframe interval 300 or in a superframe prior to the superframe interval 300, the primary network node 102 may receive an interrupt that a vehicle has been turned on. In response to the vehicle being turned on, the WBMS 101 attempts to wake up by activating the primary network node 102 and all secondary network nodes 106. As mentioned above, the WBMS 101 may attempt to complete this wake-up process within 300 milliseconds to meet certain performance requirements. To complete the startup process, the primary network node 102 verifies that all secondary network nodes 106 are active and responsive by sending a DL to each secondary network node 106 and receiving a UL returning from each secondary network node 106. However, if one of the secondary network nodes 106 misses the DL as described herein, in some systems, that secondary network node 106 may need to wait the next superframe interval to receive the DL from the second DL transmitted by the primary network node 102. The WBMS 101 cannot start up properly until all secondary network nodes 106 have received the DL from the primary network node 102 and responded to the primary network node 102.

[0048] 3B , the first secondary network node 206 turns on and expects to receive a DL from the primary network node 102 during the first frame 356. However, the first secondary network node 206 misses the DL transmission frame 302 from the primary network node 102 during the first wait-to-receive period 330. In response to expecting a DL but not receiving a DL, the first secondary network node 206 turns on its receiver and listens for other frames being transmitted from other secondary network nodes 106. When the first secondary network node 206 receives a transmission from another secondary network node 106, the first secondary network node 206 recognizes that the WBMS 101 is active and completes start-up operations to prepare for operation.

[0049] In this example, the first secondary network node 206 misses the DL transmission frame 302 from the primary network node 102 during the first receive wait time 330. Thus, the first secondary network node 206 fails to transmit a UL to the primary network node 102 during the first UL transmit time frame 334 (shown as "X" in FIG. 3B ). In response to missing the DL, the first secondary network node 206 enters a fourth transmit-receive frame 368 in preparation for receiving a UL from another secondary network node 106. Here, in the third frame 360, the first secondary network node 206 receives a fourth UL receive frame 372 (shown circled) during a fourth UL receive time frame 370. In this example, the second secondary network node 210 transmits the fourth UL receive frame, although the UL receive frame could be from any secondary network node 106.

[0050] The first secondary network node 206 may keep its receiver on and continue listening for UL frames during the superframe interval 300. As shown, the first secondary network node 206 enters a fifth transmit-receive frame 374 and receives a fifth UL receive frame 378 (shown circled) during a fifth UL receive time frame 376. The first secondary network node 206 may receive any number of UL frames from other secondary network nodes 106. In another example, the first secondary network node 206 may stop listening for UL frames after receiving a UL frame from another secondary network node 106.

[0051] When the first secondary network node 206 wakes up to listen for transmissions from other secondary network nodes 106, it does not need to wake up for the entire superframe. Instead, the first secondary network node 206 only needs to wake up long enough to receive a transmission from another secondary network node 106. If it does not receive a transmission from another secondary network node 106, the first secondary network node 206 may return to a sleep or idle mode. Also, if the first secondary network node 206 detects a transmission from another secondary network node 106, it may wait the next superframe interval to transmit a UL to the primary network node 102 so that it can transmit that UL during the appropriate frame.

[0052] In this example, the first secondary network node 206 misses the DL from the primary network node 102 but still turns on for the superframe interval 300. This example allows the WBMS 101 to wake up and become active quickly enough to meet certain performance requirements, especially when the WBMS 101 comes out of power save mode.

[0053] 4A and 4B illustrate exemplary consecutive superframe intervals 400 and 401 that may be used by a wireless battery management system, such as the WBMS 101. FIG. 4A illustrates superframe 400, and FIG. 4B illustrates superframe 401. In FIGS. 4A and 4B, a secondary network node (e.g., 206, 210, 301, etc.) misses a downlink from the primary network node 102. FIGS. 4A and 4B illustrate an example of an exemplary secondary network node 106's response to missing the downlink from the primary network node 102. In FIGS. 4A and 4B, similar components operate in the same manner as similar components described above with reference to FIGS. 3A and 3B. For example, receive time frames, DL receive frames, UL transmit frames, receive-transmit frames, etc. each operate in FIGS. 4A and 4B in the same manner as similarly named corresponding frames in FIGS. 3A and 3B.

[0054] For example, primary network node 102 communicates with first secondary network node 206, second secondary network node 210, and Nth secondary network node 301 using superframe intervals 400 (shown in FIG. 4A ) and 401 (shown in FIG. 4B ). As shown, superframe intervals 400 and 401 include a first DL guard frame 402, a first DL transmit frame 403, a first UL receive frame 404, a second UL receive frame 405, a second DL transmit frame 406, a third UL receive frame 407, a fourth UL receive frame 408, and a fifth UL receive frame 409. Superframe intervals 400 and 401 also include a first DL transmit time frame 410, a first transmit-receive frame 411, a first UL receive time frame 412, a second transmit-receive frame 413, a second UL receive time frame 414, a third transmit-receive frame 415, a third UL receive time frame 416, a second DL guard frame 417, a second DL transmit time frame 418, a fourth transmit-receive frame 419, a fourth UL receive time frame 420, a fifth transmit-receive frame 421, a fifth UL receive time frame 422, a sixth transmit-receive frame 423, and a sixth UL receive time frame 424.

[0055] Superframe intervals 400 and 401 also include a first receive wait time 425, a first receive-to-transmit frame 426, a first UL transmit time frame 427, a second receive wait time 428, a second receive-to-transmit frame 429, and a second UL transmit time frame 430. Superframe intervals 400 and 401 include a first DL receive frame 431 and a first UL transmit frame 432.

[0056] Superframe intervals 400 and 401 also include a third receive wait time 433, a third receive-to-transmit frame 434, a third UL transmit time frame 435, a fourth receive wait time 436, a fourth receive-to-transmit frame 437, and a fourth UL transmit time frame 438. Superframe intervals 400 and 401 also include a second DL receive frame 439, a second UL transmit frame 440, a third DL receive frame 441, and a third UL transmit frame 442.

[0057] Superframe intervals 400 and 401 include a fifth receive wait time 443, a fifth receive-to-transmit frame 444, a fifth UL transmit time frame 445, a sixth receive wait time 446, a sixth receive-to-transmit frame 447, and a sixth UL transmit time frame 448. Superframe intervals 400 and 401 also include a fourth DL receive frame 449, a fourth UL transmit frame 450, a fifth DL receive frame 451, and a sixth UL transmit frame 452. Superframe intervals 400 and 401 also include a first frame 453, a second frame 454, a third frame 455, a fourth frame 456, a fifth frame 457, a sixth frame 458, a seventh frame 459, and an eighth frame 460. Frames 453-460 may be referred to herein as slots 453-460, respectively.

[0058] A detailed description of the operation of Figures 4A and 4B will be omitted here for the sake of brevity. However, Figures 4A and 4B operate similarly to Figures 3A and 3B. In Figures 4A and 4B, the primary network node 102 transmits a first DL transmission frame 403 during the first frame 453. In this example, the first secondary network node 206 misses the DL transmission. The "X" during the first wait-to-receive period 425 in Figure 4A indicates the missed DL transmission. Other secondary network nodes 106 (210, 301, etc.) in this example receive the DL transmission. Because the first secondary network node 206 missed the DL transmission, the first secondary network node 206 does not transmit a UL transmission frame during the first UL transmission time frame 427. In this example, rather than listening for UL transmissions from other secondary network nodes 106 during superframe interval 400 (as described above with reference to FIG. 3B), the first secondary network node 206 listens for DL ​​transmissions from the primary network node 102 during the next superframe interval 401. If a transmission occurs during superframe interval 401, the WBMS 101 is likely operating, and the first secondary network node 206 can continue normal operation. As shown in FIG. 4A, the first secondary network node 206 does not listen for UL transmissions from other secondary network nodes 106 during superframe interval 400. Instead, the first secondary network node 206 listens for transmissions during superframe interval 401, and in this example receives the DL transmission in first DL receive frame 431. The first secondary network node 206 then responds to the primary network node 102 with first UL transmit frame 432. Thus, the maximum delay in this example scenario is one superframe.

[0059] 5A and 5B are example graphs of node power consumption in accordance with various examples herein. FIG. 5A is a graph 500 of scaled power consumption for secondary network nodes in accordance with various examples herein. The Y-axis of graph 500 indicates scaled power consumption, and the X-axis indicates the number of network nodes for four different scenarios. Examples are shown for 8 nodes, 16 nodes, 24 nodes, and 32 nodes. The four scenarios shown for each node count are the original scenario, the keep-alive frequency increased scenario, the receive (RX) in UL frame scenario, and the receive (RX) in next superframe scenario. In one example, the primary node may transmit keep-alive frames at intervals of less than 300 milliseconds in this scenario. In the original scenario, a node that misses the DL waits for the next active frame. In the keep-alive frequency increased scenario, the keep-alive frequency is increased so that relatively more superframes have keep-alive signals while relatively fewer superframes remain idle. The scenario for receiving (RX) in an UL frame involves a first secondary network node listening to an UL from another secondary network node in a first superframe if the first secondary network node misses a DL in the first superframe. This scenario was described above with reference to Figure 3B. The scenario for receiving (RX) in a next superframe involves a first secondary network node listening to an UL from another secondary network node in a second superframe if the first secondary network node misses a DL in the first superframe. This scenario was described above with reference to Figures 4A and 4B.

[0060] In the original scenario in graph 500, the scaled power consumption is approximately 4.0 per node for each node count (8, 16, 24, and 32). In the increased keep-alive frequency scenario, the scaled power consumption is approximately 7.0 per node for each node count. In the receive in UL frame (RX) scenario, the scaled power consumption per node ranges from approximately 4.1 to 4.3 for various node counts. In the receive in next superframe (RX) scenario, the scaled power consumption per node is approximately 5.0 for various node counts. Thus, graph 500 shows that the receive in UL frame (RX) scenario or the receive in next superframe (RX) scenario consumes less power in the secondary nodes than the increased keep-alive frequency scenario.

[0061] 5B is a graph 550 of scaled power consumption for a main node (e.g., primary network node 102) in accordance with various examples herein. The Y-axis of graph 550 shows scaled power consumption, and the X-axis shows the number of network nodes for four different scenarios. Examples are shown for 8 nodes, 16 nodes, 24 nodes, and 32 nodes. The four scenarios shown for each node count are the original scenario, the keep-alive frequency increase scenario, the receive (RX) in UL frame scenario, and the receive (RX) in next superframe scenario, which are described above.

[0062] In the original scenario in graph 550, the scaled power consumption at the main node is approximately 11 for 8 secondary nodes, approximately 19 for 16 secondary nodes, approximately 27 for 24 secondary nodes, and approximately 35 for 32 secondary nodes. In the keep-alive frequency augmentation scenario, the scaled power consumption at the main node is approximately 14 for 8 secondary nodes, approximately 22 for 16 secondary nodes, approximately 30 for 24 secondary nodes, and approximately 39 for 32 secondary nodes. In the receive (RX) scenario in the UL frame, the scaled power consumption at the main node is approximately 11 for 8 secondary nodes, approximately 19 for 16 secondary nodes, approximately 27 for 24 secondary nodes, and approximately 35 for 32 secondary nodes. In the receive (RX) scenario in the next superframe, the scaled power consumption at the main node is approximately 11 for 8 secondary nodes, approximately 19 for 16 secondary nodes, approximately 27 for 24 secondary nodes, and approximately 35 for 32 secondary nodes. Thus, graph 500 shows that the receive (RX) in the UL frame scenario or the receive (RX) in the next superframe scenario consumes less power in the secondary node than the keep-alive frequency increase scenario. Thus, graph 550 shows that the receive (RX) in the UL frame scenario or the receive (RX) in the next superframe scenario consumes less power in the primary node than the keep-alive frequency increase scenario.

[0063] FIG. 6 is a table 600 illustrating approximate power consumption at a main node and secondary network nodes for a network of N nodes in accordance with various examples herein. In this example, the secondary nodes transmit every 3T and receive every T, where T is the time interval. The main node transmits every T and receives every 3T. Column 602 illustrates various scenarios. Column 604 illustrates approximate power consumption at a secondary node, assuming transmit power is approximately equal to receive power. Column 606 illustrates approximate power consumption at a main node, assuming transmit power is approximately equal to receive power. Row 608 is the header row, and rows 610, 612, 614, and 616 illustrate the four different scenarios described above (original, keep-alive frequency increase, RX in UL frame, and RX in next superframe), respectively. The numbers in table 600 are approximate values.

[0064] In one example, the original scenario (row 610) has a secondary node power consumption of 4 and a main node power consumption of 3+N. The keep-alive frequency increased scenario (row 612) has a secondary node power consumption of 7 and a main node power consumption of 6+N. This scenario therefore consumes more power than the original scenario also shown in Figures 5A and 5B.

[0065] Referring back to Figure 6, in the receive (RX) scenario for the UL frame, the power consumption of the secondary node is 4 + (N - 1) x p, where p is the probability of error. In the receive (RX) scenario for the UL frame, the power consumption of the primary node is 3 + N. As an example, in a system with eight secondary nodes and a 10% probability of error, the power consumption of the secondary nodes in this scenario is 4 + (8 - 1) (0.10), or approximately 4.7. If the probability of error were to be 0.1%, the power consumption of the secondary nodes would be 4 + (8 - 1) (0.001), or approximately 4.007. Therefore, a decrease in the probability of error reduces power consumption. Also, in this scenario, an increase in N increases the power consumption of the secondary nodes.

[0066] In the receive (RX) scenario in the next superframe, the power consumption of the secondary node is 4 + 1 / (1 - p), where p is the probability of error. In the receive (RX) scenario in the next superframe, the power consumption of the main node is 3 + N. As an example, in a system with eight secondary nodes and a 10% error probability, the power consumption of the secondary node in this scenario is 4 + 1 / (0.9), or approximately 5.1. If the error probability becomes 0.1%, the power consumption of the secondary node is 4 + 1(0.999), or approximately 5.001. Therefore, even in this scenario, reducing the error probability reduces power consumption.

[0067] 7 is a flowchart of a method for restarting a network from a power saving mode, in accordance with various examples herein. The steps of method 700 may be performed in any suitable order. The hardware components described above with reference to FIGS. 1-2 may perform method 700 in some examples.

[0068] Method 700 begins at 710, where primary network node 102 transmits downlink packets to one or more secondary nodes in a first superframe of a WBMS. In one example, the first superframe is superframe 300, and the secondary nodes may be secondary nodes 206, 210, and / or 301.

[0069] Method 700 continues at 720, where the first secondary node receives the downlink packet. In one example, secondary node 206 fails to receive the downlink packet and secondary node 210 receives the downlink packet. Thus, in this example, secondary node 210 is the first secondary node. In response to failing to receive the expected downlink packet, secondary node 206 may turn on its receiver and listen for uplink packets from other secondary nodes (e.g., 210, 301).

[0070] The method 700 continues at 730, where the first secondary node (e.g., node 210) transmits a first uplink packet from the first secondary node to the primary network node 102 in a first superframe (e.g., superframe 300). In one example, the first uplink packet is transmitted using the second UL transmission frame 338.

[0071] The method 700 continues at 740, where a second secondary node (e.g., node 206) receives a first uplink packet in the first superframe. In one example, the first uplink packet is received in the fourth UL receive frame 372. As described above, the second secondary node 206 listens for uplink packets from other secondary nodes, such as node 210. When the second secondary node 206 receives the uplink packet, the second secondary node 206 recognizes that the WBMS 101 is active and can then prepare for operation.

[0072] The method 700 continues at 750, where the second secondary node transmits a second uplink packet during the second superframe to the primary network node 102. The second secondary node (e.g., node 206) waits for the next superframe after the first superframe so that the second secondary node 206 can transmit the second uplink packet during the appropriate slot.

[0073] 8 is a flowchart of a method for restarting a network from a power-saving mode, in accordance with various examples herein. The steps of method 800 may be performed in any suitable order. The hardware components described above with reference to FIGS. 1-2 may perform method 800 in some examples. Method 800 may be performed when a WBMS exits a low-power state, such as a sleep or idle state, to reactivate all nodes in the WBMS.

[0074] The method 800 begins at 810, where the primary network node 102 transmits a first downlink packet to one or more secondary nodes in a first superframe of the WBMS. In one example, the first superframe may be superframe 400, and the secondary nodes may be secondary nodes 206, 210, and / or 301. The first downlink packet may be transmitted in a first slot of superframe 400.

[0075] Method 800 continues at 820, where a first secondary node receives a first downlink packet in a first superframe (e.g., superframe 400). The first downlink packet may be received in a first slot of superframe 400. In one example, secondary node 206 fails to receive the downlink packet and secondary node 210 receives the downlink packet. Thus, in this example, secondary node 210 is the first secondary node. In response to failing to receive the expected downlink packet, secondary node 206 may be configured to turn on its receiver and listen for uplink packets from other secondary nodes (e.g., 210, 301).

[0076] The method 800 continues at 830, where a second secondary node (e.g., node 206) fails to receive the first downlink packet in the first superframe. In one example, the "X" during the first wait-to-receive period 425 in FIG. 4A indicates a missed DL transmission at node 206. The secondary node 206 may miss the first downlink packet due to interference or because the secondary node 206 is not listening for the first downlink packet when the primary node sends it.

[0077] The method 800 continues at 840, where a first secondary node (e.g., node 210) transmits a first uplink packet to the primary network node 102 in the first superframe 400. By way of example, the first uplink packet is transmitted using the second UL transmission frame 440. Node 210 sends the first uplink packet in response to receiving the first downlink packet. Each secondary node may be able to determine its respective slot within the superframe 400, as described in commonly assigned U.S. patent application Ser. No. 17 / 828,895, entitled "Efficient Unicast Superframe Communication," filed May 31, 2022, which is hereby incorporated by reference in its entirety. [Patent Document 4] U.S. Patent Application No. 17 / 828,895

[0078] The method 800 continues at 850, where the primary network node 102 transmits a second downlink packet to one or more secondary nodes in a second superframe. In one example, the second superframe may be superframe 401, and the first and second superframes may be consecutive superframes. In one example, the second downlink packet may be transmitted using a second DL transmission frame 406. The second downlink packet may be transmitted in a second slot of superframe 401.

[0079] The method 800 continues at 860, where a second secondary node (e.g., node 206) receives a second downlink packet in the second superframe 401. In one example, the second downlink packet is received in the first DL receive frame 431. The second downlink packet may be received in a second slot of the second superframe 401.

[0080] The method 800 continues at 870, where a second secondary node (e.g., node 206) transmits a second uplink packet to the primary network node 102 in the second superframe 401. As an example, the second uplink packet is transmitted in the first UL transmission frame 432. The second uplink packet may be transmitted in the third slot of the second superframe 401.

[0081] In the example herein, a first secondary node that fails to receive an expected downlink packet from a primary node during an active superframe may conveniently turn on its receiver to listen for other frames being transmitted to the primary node from other secondary nodes during this active superframe. When the first secondary node receives a transmission from another secondary node, the first secondary node wakes up and enters an active state. In another example herein, a first secondary node that misses a downlink packet from a primary node may use its receiver to listen during the next superframe instead of the current superframe. If there is any activity in the next superframe, the WBMS becomes active and the first secondary node can continue normal operation. In the example herein, the node consumes minimal power while in the off state (e.g., keep-alive power-saving state) and can still wake up quickly, enabling the WBMS to operate in less than 300 milliseconds.

[0082] The term "coupled" is used throughout this specification. This term may encompass a connection, communication, or signal path that enables a functional relationship consistent with this description. For example, in a first example, device A is coupled to device B if device A generates a signal to control device B to perform an operation, or in a second example, device A is coupled to device B via an intervening component C such that device B is controlled by device A via control signals generated by device A, where intervening component C does not substantially change the functional relationship between device A and device B.

[0083] A device that is "configured" to perform a task or function may be configured (e.g., programmed and / or hardwired) to perform that function by a manufacturer at the time of manufacture, and / or may be configurable (or reconfigurable) by a user after manufacture to perform that function and / or other additional or alternative functions. Such configuring may be achieved by firmware and / or software programming of the device, by the construction and / or layout of the hardware components and interconnections of the device, or by a combination of these.

[0084] Unless otherwise stated, "about," "approximately," or "substantially" before a value means ±10 percent of the stated value. Variations in the described examples are possible, and other examples are possible, within the scope of the claims.

Claims

1. 1. A wireless battery management system (WBMS), comprising: one or more sets of battery cells; a primary node configured to broadcast a downlink packet in a first superframe; a first secondary node coupled to a first set of battery cells, the first secondary node comprising: receiving the downlink packet; transmitting a first uplink packet to the primary node during the first superframe; the first secondary node, configured so that a second secondary node coupled to a second set of battery cells, the second secondary node comprising: receiving the first uplink packet from the first secondary node in the first superframe; transmitting a second uplink packet to the primary node during a second superframe; the second secondary node, configured so that Including WBMS.

2. 2. The WBMS according to claim 1, wherein the first superframe and the second superframe are consecutive superframes.

3. The WBMS of claim 1 , wherein the second secondary node fails to receive the downlink packet.

4. 4. The WBMS of claim 3, wherein the second secondary node includes a receiver, and in response to failing to receive the downlink packet, the second secondary node turns on the receiver.

5. 2. The WBMS of claim 1, wherein the first secondary node receives the downlink packet in a first slot of the first superframe and transmits the first uplink packet in a second slot of the first superframe.

6. 6. The WBMS of claim 5, wherein the second secondary node receives the first uplink packet in the second slot.

7. 1. A method comprising: transmitting a downlink packet from a primary node to one or more secondary nodes in a first superframe in a wireless battery management system (WBMS); receiving the downlink packet at a first secondary node; transmitting a first uplink packet from the first secondary node to the primary node in the first superframe; receiving the first uplink packet at a second secondary node in the first superframe; transmitting a second uplink packet from the second secondary node to the primary node during a second superframe; A method comprising:

8. 8. The method of claim 7, wherein the first secondary node is coupled to a first set of battery cells and the second secondary node is coupled to a second set of battery cells.

9. 8. The method of claim 7, wherein the primary node transmits the downlink packet in a first slot of the first superframe, and the first secondary node receives the downlink packet in the first slot.

10. 10. The method of claim 9, wherein the first secondary node transmits the first uplink packet in a second slot of the first superframe.

11. The method of claim 10 , wherein the second secondary node fails to receive the downlink packet.

12. 12. The method of claim 11, wherein the second secondary node includes a receiver, and wherein in response to failing to receive the downlink packet, the second secondary node turns on the receiver.

13. 13. The method of claim 12, wherein the second secondary node receives the first uplink packet in the second slot.

14. 8. The method of claim 7, wherein the first superframe and the second superframe are consecutive superframes.

15. 1. A method comprising: transmitting a first downlink packet from the primary node to one or more secondary nodes in a first superframe; receiving the first downlink packet at a first secondary node in the first superframe; failing to receive the first downlink packet at a second secondary node in the first superframe; and transmitting a first uplink packet from the first secondary node to the primary node in the first superframe; transmitting a second downlink packet from the primary node to the one or more secondary nodes in a second superframe; receiving the second downlink packet at the second secondary node in the second superframe; and transmitting a second uplink packet from the second secondary node to the primary node in the second superframe; A method comprising:

16. 16. The method of claim 15, wherein the first superframe and the second superframe are consecutive superframes.

17. 16. The method of claim 15, wherein the first secondary node is coupled to a first set of battery cells and the second secondary node is coupled to a second set of battery cells.

18. 16. The method of claim 15, wherein the primary node transmits the first downlink packet in a first slot of the first superframe, and the first secondary node receives the first downlink packet in the first slot.

19. 20. The method of claim 18, wherein the primary node transmits the second downlink packet in a second slot of the second superframe, and the second secondary node receives the second downlink packet in the second slot of the second superframe.

20. 20. The method of claim 19, wherein the second secondary node transmits the second uplink packet in a third slot of the second superframe.

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