SHEAR WALL WITH INTEGRATED CONDUCTORS

A battery system includes one or more shear walls to provide support. A shear wall may include a support structure and conductive traces to route signals or measurements without the need for wire runs. The support structure may help to maintain the arrangement of battery cells of the battery system, while the conductive traces allow voltages among the battery cells to be monitored. Busbars, or other electrical terminals, may be coupled to the conductive traces of the shear wall, and processing equipment may also be coupled to the conductive traces. Accordingly, the processing equipment may monitor voltage among the battery cells, which may allow balancing among battery modules, diagnostics, and other functions. The shear wall may be constructed of FR-4 or other circuit board material, and the conductive traces may include bonded copper, or other electronically conductive material.

BACKGROUND

Battery packs for electrical vehicles are sometimes housed to protect them from vehicle crashes, vibration, and stresses that may impact the structure. Typical battery packs include groups of battery cells connected in parallel to increase current flow, and in series to increase voltage. Measurements and monitoring of the battery cells, or groups thereof, typically require wires to be routed within the battery pack. It is also usually non-trivial to make electrical connections between a wire and a busbar. It would be advantageous to reduce the use of wire and connectors for monitoring a battery pack. It would also be advantageous to not have to include wire runs within the battery pack.

SUMMARY

In some embodiments, a shear wall is configured to provide structural support to a battery system. The shear wall includes a support structure that is configured to provide rigidity to the battery system along at least one side of the battery system. The shear wall also includes a plurality of conductive traces layered onto the support structure. The plurality of conductive traces each include a first terminal configured to be coupled to a busbar of the battery system and a second terminal configured to be coupled to processing equipment. Accordingly, the conductive traces allow the processing equipment to measure, and optionally monitor, the voltage at one or more busbars, without having to install wire runs. In some embodiments, a busbar is connected to respective like-polarity terminals of a group of battery cells.

In some embodiments, the shear wall also includes at least one temperature sensor affixed to the support structure and corresponding conductive traces. These conductive traces include a first terminal configured to be coupled to the at least one temperature sensor, and a second terminal configured to be coupled to the processing equipment. Accordingly, the conductive traces allow the processing equipment to receive signals from one or more sensors, without having to install wire runs. In an illustrative example, a temperature sensor includes a thermistor, a thermocouple, or a resistance temperature detector.

In some embodiments, the shear wall includes an electrical connector, which includes respective pins coupled to each of the respective second terminals. In some embodiments, the processing equipment is coupled to a second electrical connector, and each of the second terminals is configured to be coupled to the processing equipment by connecting the first electrical connector and the second electrical connector. For example, a cable having plugs at both ends may couple the first and second connectors so that the processing equipment may measure voltages of the second terminals.

In some embodiments, the support structure is made at least in part of a flame-resistant glass-epoxy laminate. In some embodiments, the conductive traces include copper tracks bonded to the support structure. In some embodiments, the conductive traces may include gold, silver, or other metals. In some embodiments, the support structure includes at least one extension (e.g., a tab or other protrusion), which includes a conductive pad. The conductive pad is coupled to a first terminal, and the conductive pad is configured to be coupled to the busbar. Accordingly, the extension provides a coupling location for electrically coupling a busbar to conductive traces of the shear wall. For example, in some embodiments, a first terminal is configured to be coupled to the busbar by a screw terminal. In a further example, in some embodiments, the first terminal is configured to be coupled to the busbar by a welded connection.

In some embodiments, the shear wall is included in a battery system. For example, a battery system includes processing equipment, a plurality of battery cells connected to a plurality of busbars, at least one shroud, and a shear wall. The at least one shroud is configured to maintain an arrangement of the plurality of battery cells. The shear wall is configured to provide structural support to the at least one shroud and the arrangement of the plurality of battery cells. The shear wall includes a support structure coupled to the at least one shroud along at least one side of the at least one shroud. The shear wall also includes a plurality of conductive paths affixed to the support structure. The plurality of conductive paths each include a respective first terminal configured to be coupled to a respective busbar, and a respective second terminal configured to be coupled to the processing equipment.

DETAILED DESCRIPTION

A battery system may include an arranged (e.g., hexagonally close-packed) group of battery cells with parallel axes, with corresponding buttons (e.g., ends having like polarity) pointed in the same direction, a plastic shroud at either end of the collective cells (e.g., to provide support and maintain the arrangement), a set of busbars mounted to the shroud at the button ends of the cells (e.g., to couple cells to one another in series and parallel), and a shear wall arranged along at least one side of the battery system configured to provide structural rigidity.

In some embodiments, the shear wall is substantially a piece of nonconductive, fiber-reinforced composite. For example, the shear wall may be constructed of a flame-retardant fiberglass. In a further example, the shear wall may be constructed of a composite that fulfills the requirements of NEMA LI 1-1998 Grade FR-4. In a further example, the shear wall may be constructed from an injection-molded or pressure-formed, fiber-reinforced polymer.

In some embodiments, a shear wall may include a printed circuit, embedded circuit, or other suitable collection of conductors, which may be coupled to the busbars, battery cells, or both. In some embodiments, the shear wall may include conductive traces that electrically connect to respective pads on the shear wall, which may be electrically connected to a respective busbar.

In some embodiments, a battery system may include processing equipment that at least partially monitors or controls the voltage balance among one or more battery systems. Accordingly, the processing equipment may be configured to measure one or more voltage signals from one or more busbars, one or more cells, or both. The integration of conductive traces in the shear wall may provide easy-to-use and fast-to-install electrical connections between processing equipment and busbars without significant added cost (e.g., from running and terminating wires, and accompanying cable management).

FIG. 1shows arrangement100, including a plan view of illustrative shear wall110having integrated conductors (e.g., conductive traces170,172,174, and176), and processing equipment130, in accordance with some embodiments of the present disclosure. Shear wall110may represent one side wall of a battery module, providing structural support and rigidity as well as conductive traces for routing electrical measurements. Shear wall110includes a support structure112, which may be configured to, for example, provide rigidity to components of a battery module. Shear wall110includes extensions113,115,117, and119, having corresponding first terminals140,142,144, and146. First terminals140,142,144, and146may be configured to be coupled to corresponding busbars, battery cells, or both.

Processing equipment130may include any suitable circuitry for processing signals received from conductive traces of shear wall110(e.g., via cable132and connector131). For example, processing equipment130may include signal conditioning circuitry (e.g., filters, amplifiers, voltage dividers), an analog to digital converter, any other suitable circuitry, or any combination thereof. Processing equipment130may, in some embodiments, include a processor, a power supply, power management components (e.g., relays, filters, voltage regulators), input/output IO (e.g., GPIO, analog, digital), memory, communications equipment (e.g., CANbus hardware, Modbus hardware, or a WiFi module), any other suitable components, or any combination thereof. In some embodiments, processing equipment130may include one or more microprocessors, microcontrollers, digital signal processors, programmable logic devices, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), etc., and may include a multi-core processor. In some embodiments, processing equipment130may be distributed across multiple separate processors or processing units, for example, multiple of the same type of processing units or multiple different processors.

In some embodiments, processing equipment130executes instructions stored in memory for monitoring a battery system, managing a battery system, or both. In some embodiments, memory may be an electronic storage device that is part of processing equipment130. For example, memory may be configured to store electronic data, computer software, or firmware, and may include random-access memory, read-only memory, hard drives, optical drives, solid state devices, or any other suitable fixed or removable storage devices, and/or any combination of the same. Nonvolatile memory may also be used (e.g., to launch a boot-up routine and other instructions).

In some embodiments, processing equipment130may be coupled to more than one shear wall (e.g., via any suitable number of cables and connectors), corresponding to more than one battery module or more than one section of a battery module. For example, processing equipment130may be configured to balance load across the battery modules based on measured voltages.

Shear wall110includes sensor120, and corresponding conductive traces121and122for communicating sensor data from sensor120, powering sensor120, or both. Sensor120may include any suitable sensor such as, for example, a voltage sensor, a current sensor, an impedance sensor, a strain sensor (e.g., a strain gage connected to a Wheatstone Bridge circuit), a vibration sensor (e.g., a piezoelectric accelerometer), an optical sensor (e.g., a camera, photodetector, or photodiode), a proximity sensor (e.g., an ultrasound source and detector, or an infrared based system), any other suitable sensor, any suitable corresponding circuitry, or any combination thereof. In some embodiments, for example, a sensor may include surface-mount packaging (e.g., a surface-mount integrated circuit), through-hole packaging, or a combination thereof. In accordance with the present disclosure, a sensor may be bolted to, adhered to, welded to, printed on, embedded within, or otherwise affixed to, a support structure.

Sensor120may include, for example, any suitable type of temperature sensor such as a thermocouple, a thermopile, a thermistor, a resistive temperature detector (RTD), any other suitable temperature sensor, or any combination thereof. For example, in some embodiments, sensor120may include a thermistor connected across conductive traces121and122. In some such embodiments, processing equipment130may be configured to measure a voltage across conductive traces121and122to determine a corresponding temperature of sensor120, which may be indicative of a local temperature of shear wall110. In a further example, in some embodiments, sensor120may include a thermocouple junction connected across conductive traces121and122, which may include suitable respective metals corresponding to the thermocouple junction. In some such embodiments, processing equipment130may include a cold junction (e.g., which may be measured using a thermistor), and may be configured to measure a voltage across conductive traces121and122, to determine a corresponding temperature of sensor120(e.g., based on the voltage, and the temperature of the cold junction), which may be indicative of a local temperature of shear wall110. In some embodiments, a sensor may require more than two conductive traces. For example, in some embodiments, a sensor may include an RTD, which may require four conductive traces for an accurate measurement (e.g., using a four-wire measurement). In some embodiments, a sensor may require a single conductive trace. For example, a sensor may include a thermistor which may be grounded at one terminal, and only a single conductive trace is used (e.g., the processing equipment may measure the voltage of the single trace relative to a common ground). A shear wall, in accordance with the present disclosure, need not include any sensors, but may include any suitable number of sensors, each having any suitable number of corresponding conductive traces.

In some embodiments, shear wall110also includes first extension111, which may include second terminals corresponding to respective first terminals (e.g., connected by respective conductive traces). First extension111may be configured to engage with a connector (e.g., connector131), to couple conductive traces to conductors of the connector. In some embodiments, a shear wall need not include a first extension. For example, a shear wall may include a plurality of second terminals which may be respectively coupled to pins of an included connector, which may be configured to engage with a mating connector to couple the conductive traces to processing equipment.

As shown inFIG. 1, support structure112is a rectangle, having several extensions (e.g., extensions113,115,117, and119, and first extension111). In some embodiments, support structure112may be formed by being cut from a larger sheet of material. In some embodiments, for example, support structure112may be an injection-molded, or pressure-formed, fiber-reinforced polymer.

In some embodiments, conductive traces170,172,174and176may be formed on support structure112using printed circuit board (PCB) techniques. For example, a copper foil may be applied to support structure112, and etched away (e.g., chemically etched) to leave conductive traces170,172,174, and176. In a further example, a copper foil may be applied to support structure112, a photoresist applied, and excess copper may be etched away to leave conductive traces170,172,174, and176. In some embodiments, a multi-layer collection of conductive traces may be formed, wherein conductive traces may be separated by a layer of the support structure. In some embodiments, one or more ground planes (e.g., connected to a DC low output of a power supply, shielding, or chassis ground), power planes (e.g., connected to a DC high output of a power supply), or any other suitable conductive layers may be included in a shear wall. Conductive traces170,172,174, and176may be formed using any suitable conductor such as, for example, copper, gold, silver, platinum, aluminum, graphite, an alloy, or a combination thereof, and need not all include the same material.

FIG. 2shows a plan view of illustrative shear wall210having integrated conductors (e.g., conductive traces270,272,274,276,278, and280), and connectors230and236, in accordance with some embodiments of the present disclosure. Shear wall210includes support structure212, which may be configured to mechanically engage with components of a battery module to provide rigidity. Conductive traces270,272,274,276,278, and280connect respective pads240,242,244,246,248, and250to respective pins of connector230. Another set of conductive traces, not shown inFIG. 2(e.g., included on a different layer of support structure212), connect pads240,242,244,246,248, and250to respective pins of connector236, such that processing equipment may be coupled to connector230, connector236, or both, via a corresponding connector, to measure, for example, respective voltages. Pads240,242,244,246,248, and250are positioned on respective extensions213,215,217,219, and221, and are configured to electrically couple to respective terminals of a battery system (e.g., terminals of a busbar, terminals of one or more battery cells, or a chassis ground).

Connectors230and236may include any suitable type of electric connector such as, for example, a Deutsch D™ connector, a Molex® connector, a spade connector, a connector having pins, a spring terminal connector, a screw terminal connector, a d-sub connector (e.g., DB-9 connector), an RJ45 connector, an RJ11 connector, an Amphenol connector (e.g., a mil-spec twist-lock connector), a BNC connector, a PCB-mount header, any other suitable electrical connector having any combination of interconnect engagements of any suitable gender (e.g., pins, spades, plugs, sockets), or any combination thereof. In some embodiments, a shear wall may include one connector, more than one connector (e.g., as shown illustratively inFIG. 2), or no connectors (e.g., solder pads may be provided to directly affix wires). In some embodiments, respective pins of connectors230and236may be soldered onto conductive pads of respective conductive traces270,272,274,276,278, and280. In some embodiments, connectors230and236may include a locking feature, a strain relief feature, any other suitable feature, or any combination thereof.

Extensions213,215,217,219, and221may be configured for arranging respective conductive pads240,242,244,246,248, and250nearer to measurement locations (e.g., at battery cell terminals, busbars, or other suitable locations). In some embodiments, a shear wall need not include extensions. For example, a shear wall be a rectangle, or nearly a rectangle, and conductive pads may be located along an edge of the sheer wall, or any other suitable location of the shear wall.

FIG. 3shows a cross-section view of an illustrative battery system300, in accordance with some embodiments of the present disclosure. Battery cells301,302,303,304,305,306,307, and308may be arranged and held in place by shrouds316and318. For example, shrouds316and318may include corresponding reliefs, holes, or both, in an arrangement (e.g., a pattern such as a hexagonal close-packed type pattern), which may maintain spacing and position of battery cells301-308. Like-polarity terminals of battery cells301-308are each connected to busbar314via respective jumpers309(e.g., in recesses of busbar314shown inFIG. 3as through-holes). For example, each of jumpers309(i.e., corresponding to each of battery cells301-308) may be soldered wires, ultrasonically welded wires, flex tabs which engage with corresponding tabs, springs, or any other suitable electrical jumper from a respective battery cell terminal to busbar314. The other respective poles (not shown inFIG. 3) of battery cells301-308are not connected to busbar314, and accordingly may be connected to one or more other busbars or other conductive components. For example, as shown inFIG. 3, terminals of battery cells301-308are connected in parallel via busbar314. Further, battery cells301-308may be, for example, connected to another busbar (not shown inFIG. 3) via the other polarity terminals of battery cells301-308(e.g., the busbars may be connected in series with each other across battery cells301-308which accordingly would be connected in parallel).

Shear walls310and312are connected to shrouds316and318to provide rigidity to prevent deformation of the arrangement of battery cells301-308due to shear forces, or other forces which may cause deformation. For example, shear walls310and312may help lend rigidity to the arrangement of battery cells301-308in directions along axis390, axis392, an axis perpendicular to both axis390and axis392(e.g., directed into the page, or out of the page), or any combination thereof. In a further example, shear walls310and312may reduce a force on one or more of battery cells301-308(e.g., by reducing compressive forces along axis392from gravity). In a further example, in the context of an electric car having a battery system, shear walls310and312may provide rigidity in the event of a vehicle crash (e.g., increased loading from impact and vehicle deformation). In a further example, in the context of an electric car having a battery system, shear walls310and312may provide spatially controlled rigidity in the event of a vehicle crash (e.g., yield at predetermined locations, and hold rigid in other locations). Shear walls310and312may be connected to shrouds316and318by bolted connections, soldered connections, welded connections, brazed connections, crimp connections, tight fitment (e.g., interference press fit, snap features, tongue and groove), any other suitable connection type to form a suitably rigid structure, or any combination thereof.

Shear wall310includes support structure311and conductive traces370,372,374, and376, which provide conductive paths partially embedded in support structure311(as shown inFIG. 3). Conductive traces may be overlaid on the surface of support structure311, fully embedded in support structure311(e.g., covered by an insulating layer), partially embedded, or any suitable combination thereof. Conductive trace376, for example, may be coupled to pad320(e.g., connected out of the cross-section plane), and may serve as a voltage tap for busbar314(e.g., via jumper322connecting busbar314to conductive pad320). For example, conductive traces370,372,374, and376may be coupled to respective busbars, and also respective terminals of processing equipment (e.g., via a suitable connector and/or cable) configured to measure voltages of the respective busbars over time.

In accordance with the present disclosure, one or more busbars of battery system300may be monitored by processing equipment without the need for wire runs near and around the battery cells. In some embodiments, the integration of conductive paths (e.g., conductive traces370,372,374, and376) into shear wall310may provide a convenient path as compared to individual wires. For example, wires may require strain relief, and cable management hardware, and may be susceptible to snagging, shorting, vibrating, or getting in the way during assembly and maintenance. Shear wall312, as shown inFIG. 3, includes a support structure but no conductive traces. A battery system may include any suitable number of shear walls having any suitable number of conductive traces. For example, a battery system may include two shear walls having conductive traces, on opposite lateral sides of the system. In a further example, a battery system may include four shear walls having conductive traces, on all lateral sides of the system. In a further example, a battery system may include a single shear wall having conductive traces on a lateral side, and shear walls without conductive traces on the remaining lateral sides (e.g., three remaining walls if the battery system is rectangular).

FIG. 4shows a side view of an illustrative battery system400, in accordance with some embodiments of the present disclosure. Battery system400may include battery cells (not shown), a structure (e.g., shear wall410and a shear wall not shown inFIG. 4on the opposite side of battery system400, lateral sides440and442, and shrouds414and415), busbars401-405, and processing equipment490, along with any other suitable components. Shear wall410includes extensions450,452,454,456, and458which protrude through a side of shroud414, thereby being easily accessible to busbars401-405. Shear wall410includes conductive traces (e.g., conductive trace460) and sensors (e.g., sensor470), which are shown as dashed lines inFIG. 4(e.g., traces are embedded in the support structure of shear wall410). The conductive traces of shear wall410terminate at one end at connector492. A set of the conductive traces also terminate at extensions450,452,454,456, and458, while other conductive traces terminate at sensors.

FIG. 5shows a top view of illustrative battery system400ofFIG. 4, in accordance with some embodiments of the present disclosure. Shown additionally inFIG. 5is cable496, having connectors497and495, which couple connector492of shear wall410to connector491of processing equipment490, and shear wall412, which is across from shear wall410. In some embodiments, processing equipment may include more than one connector, and be configured to couple to more than one shear wall. In some embodiments, processing equipment may be connected directly to a shear wall, without the need for a cable. For example, in some embodiments, lateral side440may include conductive traces which engage with conductive traces of shear wall410, and the conductive traces of lateral side440may also electrically couple to processing equipment490.

FIG. 6shows a perspective view of exploded battery system structure600, including shrouds630,632,634, and636, and shear walls620,622,624, and626, in accordance with some embodiments of the present disclosure. Battery system600includes two battery modules610and612, connected by mount640. In some embodiments, mount640may include a cooling plate, a structural plate, an isolation barrier, mounting hardware, or any combination thereof. Battery module610includes shrouds630and632, which are connected to shear walls620and622. Battery module612includes shrouds630and632, which are connected to shear walls620and622.

In some embodiments, battery modules610and612may each include a plurality of battery cells (not shown inFIG. 6), suitably connected by busbars (not shown inFIG. 6). Each of, or any of, shear walls620,622,624, and626may include conductive traces, which may be configured to couple busbars, or terminals of battery cells, to processing equipment. In some embodiments, the processing equipment may couple to conductive traces of one or more of shear walls620,622,624and626. A battery system may include any suitable number of battery modules, having any suitable number of shrouds, and any suitable number of shear walls.

FIG. 7shows a side view of a cross-section of a portion of illustrative battery system700, including two battery modules710and712, and processing equipment750, in accordance with some embodiments of the present disclosure. Battery modules710and720are coupled by mount740, which may provide structural support. Battery module710includes shear wall712, shrouds714and716, busbar711, and conductive trace713. Battery module720includes shear wall722, shrouds724and726, busbar721, and conductive trace723. Conductive trace713electrically couples busbar711to terminal753, via cable751, of processing equipment750. Conductive trace723electrically couples busbar721to terminal754, via cable752, of processing equipment750. As shown inFIG. 7, cables751and752are welded (e.g., ultrasonic welded, or laser welded) to terminals753and754, as well as conductive traces713and723(e.g., which include electrically conductive pads to allow more conductive material for welding to). In some embodiments, a soldered joint, a screw terminal, a fusible link, any other suitable connection, or any combination thereof, may be used to affix a conductive element to a conductive trace. Processing equipment750may determine respective voltages of busbars711and721, and may perform load-balancing, diagnostics, or any other suitable functions, based on the voltages. For example, in some embodiments, every busbar included in one or more battery modules of a battery system may be electrically coupled to processing equipment.

Extensions717and727are plated with conductive material which are part of respective conductive traces713and723. Although not shown inFIG. 7, shear wall712may include one or more extensions along the bottom as well (e.g., protruding through shroud716). In some arrangements, voltage taps (e.g., terminals of conductive traces) may be accessible from both the top and bottom of a shear wall. For example, a given shear wall design could be used in either battery module710or720.

Shear wall712is partially enclosed by shrouds714and716(e.g., which may be made of plastic) such that there is a substantially continuous length of shroud that is outboard of the shear wall. In some embodiments, shear wall712may be joined to each of shrouds714and716by, for example, adhesive bonding or ultrasonic welding.

A battery system may include any suitable arrangement of shrouds, shear walls, battery cells, busbars, processing equipment, any other suitable hardware, or any suitable combination thereof. For example, while busbars711and721are spaced away from extensions717and727inFIG. 7, this is illustrative and busbars711and721may be positioned directly on extensions717and727, thereby eliminating a separate element to connect busbars711and721to conductive traces713and723. In a further example with respect toFIG. 4, busbars401-405may be positioned directly on top of extensions450,452,454,456, and458, thereby eliminating a separate element to connect busbars401-405to corresponding conductive traces. In some embodiments, rather than extensions, a shear wall may include recesses that corresponding busbars may rest in. For example, in some such embodiments, the shrouds may be lower and interface with the shear wall via any suitable mechanism. In some embodiments, busbars may be integral to the shroud. For example, busbars may be bolted to, embedded in, or otherwise included as part of, a shroud. In some embodiments, a shear wall need not include extensions or recesses. For example, a shear wall may be rectangular, and may include conductive traces that terminate within the rectangular footprint. In some embodiments, all or part of a shroud may be included as part of a shear wall. In some embodiments, one or more busbars may be integrated as part of a shear wall. In some embodiments, busbars may rest or be affixed to a shear wall, a shroud, or both.