Patent Description:
One type of rechargeable battery is a lithium-ion battery, comprising a number of serially connected cells. The battery is typically housed in an enclosure to form a battery module. During normal operating conditions, electrical energy is converted to and stored as chemical energy during charging, and stored chemical energy is converted to electrical energy during discharging.

<CIT> discloses for example already battery modules connected to a common backplane.

There are various problems with current racks for battery modules. Battery modules typically include positive and negative connectors on their front face, to which power cable assemblies are connected to form a string of modules terminating at a switchgear (or pack controller). Coolant inlet and outlet connections are typically also provided on the front face of the battery module. External flexible hoses connect these coolant fittings to external rigid pipes mounted on the front surfaces of the rack system. Such connections are often difficult and labour-intensive to install and service, are subject to poor manufacturing quality due to crimping issues, and still further are easy to miss-wire by the installer/servicer, which can lead to a short circuit. Furthermore, as the cables are often exposed on the front face of the rack they are subject to impact / mechanical damage from other equipment or activity. With the cabling exposed on the front face of the modules, battery packs are also at a risk of coolant leaks where coolant can spill onto the floor in the immediate area of the battery room leading to unsafe conditions.

With current battery packs, installation/servicing of a battery module is also a relatively involved process. In order to install or remove a module from the battery pack, connection / disassembly of all of the individual interfaces mentioned above is generally required until the module is free to be installed/removed from the rack.

Still further, multiple cable lengths are often required to accommodate the various physical arrangements of the battery modules. This can result in complex and excessively long power circuits. Often the power circuit will cross over itself with the cable jackets in contact with one another, leading to potential hot spots. The overall loop area formed as a result of the cabling can be large, potentially causing electromagnetic interference (EMI) issues.

Yet further, because of the high power output of such battery systems, the main power connectors are sometimes subject to overheating. It is common practice in the industry to regularly inspect the high voltage connectors to determine if they are overheating. This is typically done visually, for example by imaging the connectors using a commercially available infrared camera. This can be a time-consuming procedure, and it would be advantageous if improved, alternative methods of inspecting high voltage connectors were available.

The present disclosure seeks to address these and other needs in the art.

In a first aspect of the disclosure, there is provided a battery system comprising a backplane for engaging with one or more battery modules as defined in claim <NUM>.

Each battery module may comprise more than one module power connector. Each module power connector and/or each backplane power connector may comprise one or more of the temperature-sensitive electronic components. The backplane may be coupled to a racking structure defining one or more battery bays, and moving the battery module into engagement with the backplane may comprise sliding the battery module into a battery bay until it engages with the backplane. A temperature-sensitive electronic component may comprise any component capable of measuring temperature, such as a temperature sensor, or may comprise a component which may be used to indirectly measure temperature. For example, the component may have a measurable property which changes as a function of temperature, and the measurable property may be monitored in order to derive temperature.

With the above battery system, monitoring of the temperature of the power connectors (either of the modules or of the backplane) may be carried out without the need to rely on infrared cameras or the like, by instead using temperature-sensitive electronic components disposed within thermally conductive distance of the module power connector and/or the backplane power connector. This may be particularly useful when a blind mate engagement is used, as described below, which can lead to the module and backplane power connectors being inaccessible when engaged to one another.

The module power connector may be configured to engage with the corresponding backplane power connector in a blind mate engagement. A blind mate engagement may be achieved by sliding a battery module into operational engagement with the backplane. Power connections may be formed when power pins (which may be comprised in the module power connector) at the rear of the battery module engage with power sockets (which may be comprised in the backplane power connector) secured within the backplane (or, in the reverse case, power pins in the backplane may engage with sockets in the battery module). The power sockets may each be connected to busbars such that, when all the battery modules are engaged with the backplane, a complete series string is formed, with both ends of the string (positive and negative) terminating at a power switchgear device, which may be referred to as a pack controller. The interconnecting busbars may be flexible to allow for slight misalignment of the module power connector relative to the backplane power connector, when engaging the two together, therefore allowing a correct fit with minimal force necessary to seat the connectors.

The module power connector and/or the corresponding backplane power connector may comprise one or more alignment features for guiding engagement of the module power connector with the corresponding backplane power connector such that, when moving the battery module into engagement with the backplane, the one or more alignment features may correct for at least some misalignment of the module power connector relative to the corresponding backplane power connector. The one or more alignment features may comprise one or more tapered portions provided on one or more of the module power connector and the backplane power connector.

The one or more temperature-sensitive electronic components may comprise one or more thermistors.

At least some of the one or more temperature-sensitive electronic components may be positioned on the module power connector.

At least some of the one or more temperature-sensitive electronic components may be positioned on the corresponding backplane power connector.

The module power connector and the corresponding backplane power connector may be inaccessible when the battery module is engaged with the backplane. In particular, in some embodiments it may not be possible, during engagement of the module and backplane power connectors, to visually locate the power connectors to assist in their alignment.

Each battery module may further comprise a module communication connector configured to engage with a corresponding backplane communication connector on the backplane. The module communication connector may be comprised in the module power connector, or may be a separate component to the module power connector. The backplane communication connector may be comprised in the backplane power connector, or may be a separate component to the backplane power connector.

The module communication connector and the corresponding backplane communication connector may comprise optical communication connectors. Each battery module may be configured to engage with the backplane in a blind mate engagement whereby the module communication connector is positioned within optically communicative distance of the corresponding backplane communication connector. In a battery module's operational position (i.e. when engaged with the backplane), optical connections may therefore be formed when optical ports in the module optical communication connector at the rear of the battery module come within sufficient proximity of optical ports in the corresponding backplane optical communication connector. In the operational position, a gap may be formed between the module communication connector and the corresponding backplane communication connector.

The optical medium is preferably inexpensive low-bandwidth light pipe material. The optical interface air gap is preferably small enough able to sufficiently tolerate misalignment such that generally no high-precision components or special alignment / calibration procedures are required to ensure correct alignment of the module optical communication connector with the backplane optical communication connector.

The module power connector and/or the corresponding backplane power connector may comprise one or more alignment features for guiding engagement of the module power connector with the corresponding backplane power connector such that, when moving the battery module into engagement with the backplane, the one or more alignment features correct for at least some misalignment of the module communication connector relative to the corresponding backplane communication connector. Thus, physically engaging the module power connectors with the backplane power connectors may be sufficient to bring the module communication connectors into communicative coupling with the backplane communication connectors. The communicative coupling may comprise a physical coupling (for example if electrical communication is being used) or alternatively may comprise a non-physical coupling, for example if optical communication is being used, as described above.

The battery system may further comprise a power switching device for interrupting power flow between the backplane and the one or more battery modules. The battery system may further comprise a pack controller configured, when a safety-disconnect condition is determined by the pack controller to be satisfied, to operate the power switching device so as to interrupt power flow between the backplane and the one or more battery modules. The pack controller may be configured to disconnect the one or more battery modules from a DC power bus, thereby interrupting power flow between the backplane and the one or more battery modules.

Each battery module may comprise a module controller configured to determine a power connector temperature of the module power connector and/or the corresponding backplane power connector, based on a change in temperature detected by the one or more temperature-sensitive electronic components. The module controller may comprise programmable logic such as one or more microprocessors and one or more memories cooperating together so as to carry out programmed instructions, such as software. In some embodiments, the module controller may comprise processing circuitry configured to carry out the methods described herein.

The one or more temperature-sensitive electronic components may comprise one or more thermistors. The module controller may be further configured to determine the power connector temperature based on an electrical resistance of the one or more thermistors. For example the power connector temperature may be determined based on a comparison of a reference electrical resistance electrically coupled to the module controller, and an electrical resistance of the one or more thermistors. The reference electrical resistance may be determined by a pull-down or pull-up resistor electrically coupled to the module controller.

The pack controller may be communicative with the module controller and may be further configured to determine the safety-disconnect condition has been satisfied if the power connector temperature is determined to exceed a preset temperature threshold.

The module controller may be further configured to communicate with the pack controller over a safety-disconnect loop. The module controller may be further configured to open the safety-disconnect loop if the power connector temperature is determined to exceed the preset temperature threshold, thereby preventing the module controller from communicating with the pack controller. The safety disconnect condition may be satisfied when the module controller is no longer communicating with the pack controller. The module controller may be configure to operate a relay or other switch-type device, such as an optical relay, in order to open/close the safety-disconnect loop.

The module controller may determine to no longer be communicating with the pack controller when the pack controller determines that the module controller has not communicated with the pack controller over the safety-disconnect loop for a predetermined amount of time.

The safety-disconnect loop may comprise an optical communication medium. The optical communication medium may comprise an optical fibre terminating at the backplane communication connector. Optical signals sent from the module controller to the pack controller may be transmitted through an air interface gap between the module communication connector and the backplane communication connector, via the one or more optical fibres, and may be detected by an optical receiver in the backplane communication connector, or in some other part of the backplane.

The module controller may be further configured to open the safety-disconnect loop if: a voltage of one or more cells in the battery module is determined to exceed a preset voltage threshold, the voltage being measured by a sensor electrically coupled to the module controller; a cell temperature of one or more cells in the battery module is determined to exceed a preset cell temperature threshold, the cell temperature being measured by a sensor electrically coupled to the module controller; or an ambient temperature of the battery module is determined to exceed a preset ambient temperature threshold, the ambient temperature being measured by a sensor electrically coupled to the module controller.

The module power connector may comprise module contacts and interlock contacts. The interlock contacts may be electrically coupled to the module controller and corresponding interlock contacts in the corresponding backplane power connector when the battery module is engaged with the backplane. The module controller may be further configured to open the safety-disconnect loop in response to the battery module being disengaged from the backplane.

The backplane power connector may comprise a jumper positioned such that, when the battery module is engaged with the backplane, the jumper is electrically coupled to the interlock contacts, and, when the battery module is disengaged from the backplane, the jumper is disconnected from the interlock contacts. The module controller may be further configured to open the safety-disconnect loop based on an electrical resistance across the interlock contacts. For example the module controller may be further configured to open the safety-disconnect loop by comparing of a reference electrical resistance electrically coupled to the module controller to an electrical resistance across the interlock contacts
The one or more temperature-sensitive electronic components may be: comprised in the module power connector and electrically coupled to the interlock contacts; comprised in the module power connector and electrically coupled to the module contacts; or comprised in the backplane power connector and electrically coupled to the jumper.

The one or more backplane power connectors may be movably coupled to the backplane. The one or more backplane connectors may be movably coupled to the backplane such that the one or more backplane connectors may be arranged to move laterally within a plane parallel to a plane defined by the backplane.

The backplane may further comprise a plurality of flexible busbars interconnecting adjacent backplane power connectors.

The backplane may comprise a rack for receiving the one or more battery modules. During engagement of the one or more battery modules with the rack, the rack may cooperate with the one or more battery modules such that movement of the one or more battery modules is constrained to a direction perpendicular to the backplane.

The pack controller may be further configured to: send over the safety-disconnect loop a sleep instruction to the module controller if a required power flow to/from the battery module is determined to be below a preset power threshold; and send over the safety-disconnect loop a wake-up instruction to the module controller if a required power flow to/from the battery module is determined to be above a preset power threshold. The module controller may be further configured to: operate in a low-power mode in response to receiving the sleep instruction; and operate in a normal mode in response to receiving the wake-up instruction.

In a further aspect of the disclosure, there is provided a module power connector for a battery module. The module power connector is configured to engage with a corresponding backplane power connector on a backplane, thereby forming a path for power flow between the battery module and the backplane. The module power connector comprises one or more temperature-sensitive electronic components configured to detect a change in temperature of the module power connector. The module power connector of the present aspect of the disclosure may be the module power connector described above in connection with the first aspect of the disclosure. Accordingly, the module power connector of the present aspect of the disclosure may comprise any of the features of the module power connector described above in connection with the first aspect of the disclosure.

In a further aspect of the disclosure, there is provided a backplane power connector for a backplane. The backplane power connector is configured to engage with a corresponding module power connector on a battery module, thereby forming a path for power flow between the battery module and the backplane. The backplane power connector comprises one or more temperature-sensitive electronic components configured to detect a change in temperature of backplane power connector. The backplane power connector of the present aspect of the disclosure may be the backplane power connector described above in connection with the first aspect of the disclosure. Accordingly, the backplane power connector of the present aspect of the disclosure may comprise any of the features of the backplane power connector described above in connection with the first aspect of the disclosure.

In a further aspect of the disclosure, there is provided a method of using a battery system. The method comprises providing a backplane comprising one or more backplane power connectors. The method further comprises providing one or more battery modules each comprising a module power connector configured to engage with a corresponding backplane power connector. The method further comprises providing one or more temperature-sensitive electronic components positioned within thermally conductive distance of, and configured to detect a change in temperature of, either, or both of, the module power connector and the corresponding backplane power connector. The method further comprises moving the one or more battery modules into engagement with the backplane such that each module power connector engages with a corresponding backplane power connector, thereby forming a path for power flow between the one or more battery modules and the backplane.

The engagement of each module power connector with a corresponding backplane power connector may comprise a blind mate engagement. Each module power connector and/or each corresponding backplane power connector may comprise one or more alignment features for guiding engagement of the module power connector with the corresponding backplane power connector such that, when moving the battery module into engagement with the backplane, the one or more alignment features correct for at least some misalignment of the module power connector relative to the corresponding backplane power connector.

According to the invention, there is provided a battery system comprising: a backplane for engaging with one or more battery modules, the backplane comprising one or more backplane optical communication connectors. The battery system further comprises one or more battery modules each comprising a module optical communication connector and each being configured to engage with the backplane by moving the battery module into engagement with the backplane such that the module optical communication connector engages with a corresponding backplane optical communication connector in a blind mate engagement. The battery system further comprises one or more optical fibres terminating at the one or more backplane optical communication connectors.

Each module optical communication connector may comprise one or more alignment features for guiding engagement of the module optical communication connector with the corresponding backplane optical communication connector such that, when moving the battery module into engagement with the backplane, the one or more alignment features correct for at least some misalignment of the module optical communication connector relative to the corresponding backplane optical communication connector.

Engagement of the one or more battery modules with the backplane may comprise the one or more battery modules being positioned relative to the backplane such that one or more module optical ports in each module optical communication connector are located within optically communicative distance of corresponding backplane optical ports in the corresponding backplane optical communication connector. A gap may be formed between the one or more module optical ports and the corresponding one or more backplane optical ports.

Each battery module may further comprise a module power connector configured to engage with the backplane by moving the battery module into engagement with the backplane such that the module power connector engages with a corresponding backplane power connector in the backplane. Each battery module may further comprise one or more temperature-sensitive electronic components positioned within thermally conductive distance of, and configured to detect a change in temperature of, either, or both of, the module power connector and the corresponding backplane power connector.

The module power connector and the corresponding backplane power connector may be inaccessible when the battery module is engaged with the backplane.

The battery system may further comprise a power switching device for interrupting power flow between the backplane and the one or more battery modules, the battery system further comprising a pack controller configured, when a safety-disconnect condition is determined by the pack controller to be satisfied, to operate the switching device so as to interrupt power flow between the backplane and the one or more battery modules.

Each battery module may further comprise a module controller configured to determine a power connector temperature of the module power connector and/or the backplane power connector, based on a change in temperature detected by the one or more temperature-sensitive electronic components.

The one or more temperature-sensitive electronic components may comprise one or more thermistors. The module controller may be further configured to determine the power connector temperature based on an electrical resistance of the one or more thermistors. For example the power connector temperature may be determined based on a reference electrical resistance electrically coupled to the module controller, and an electrical resistance of the one or more thermistors.

The module controller may be configured to communicate with the pack controller over a safety-disconnect loop. The module controller may be further configured to open the safety-disconnect loop if the power connector temperature is determined to exceed the preset temperature threshold, thereby preventing the module controller from communicating with the pack controller. The safety disconnect condition may be satisfied when the module controller is no longer communicating with the pack controller.

The module controller may be determined to no longer be communicating with the pack controller when the pack controller determines that the module controller has not communicated with the pack controller over the safety-disconnect loop for a predetermined amount of time.

The safety-disconnect loop may comprise the one or more optical fibres.

The corresponding backplane power connector may comprise a jumper positioned such that, when the battery module is engaged with the backplane, the jumper is electrically coupled to the interlock contacts, and, when the battery module is disengaged from the backplane, the jumper is disconnected from the interlock contacts. The module controller may be further configured to open the safety-disconnect loop based on an electrical resistance across the interlock contacts. For example, the module controller may be further configured to open the safety-disconnect loop by comparing a reference electrical resistance electrically coupled to the module controller to an electrical resistance across the interlock contacts.

The one or more temperature-sensitive electronic components are: comprised in the module power connector and electrically coupled to the interlock contacts; comprised in the module power connector and electrically coupled to the module contacts; or comprised in the corresponding backplane power connector and electrically coupled to the jumper.

The one or more backplane power connectors may be movably coupled to the backplane. The backplane may further comprise a plurality of flexible busbars interconnecting adjacent backplane power connectors.

Specific embodiments of the disclosure will now be described in conjunction with the accompanying drawings of which:.

The present disclosure seeks to provide an improved battery system. Whilst various embodiments of the disclosure are described below, the disclosure is not limited to these embodiments, and variations of these embodiments may well fall within the scope of the disclosure which is to be limited only by the appended claims.

Directional terms such as "top", "bottom", "upwards", "downwards", "vertically" and "laterally" are used in this disclosure for the purpose of providing relative reference only, and are not intended to suggest any limitations on how any article is to be positioned during use, or to be mounted in an assembly or relative to an environment.

Additionally, the term "couple" and variants of it such as "coupled", "couples", and "coupling" as used in this disclosure are intended to include indirect and direct connections unless otherwise indicated. For example, if a first article is coupled to a second article, that coupling may be through a direct connection or through an indirect connection via one or more other articles.

Furthermore, the singular forms "a", "an", and "the" as used in this disclosure are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Turning to <FIG>, there is shown a rack assembly <NUM> in accordance with an embodiment of the present disclosure. Rack assembly <NUM> comprises side walls <NUM> and <NUM> joining a base <NUM> and a top <NUM>. A dividing wall <NUM> extends from base <NUM> to top <NUM> and separates rack assembly <NUM> into a left-hand column and a right-hand column. Each column comprises multiple battery bays <NUM> for receiving battery modules. Each battery bay <NUM> is configured to receive or accept a single battery module though in other embodiments a battery bay may be configured to receive more than one battery module. Side walls <NUM>, <NUM> and dividing wall <NUM> each comprise guiding members <NUM> for assisting proper alignment of battery modules during insertion of the battery modules into rack assembly <NUM>. Base <NUM> houses an airflow chamber beneath battery bays <NUM>. The front of base <NUM> is provided with a vented duct <NUM> to allow the passage of air.

Rack assembly <NUM> further comprises a backplane <NUM> defining a rear wall of rack assembly <NUM>. The rear wall of rack assembly <NUM> is said to be on a battery module-receiving side of backplane <NUM>. Backplane <NUM> forms a rear wall of each battery bay <NUM> and comprises a number of backplane power connectors <NUM> comprising backplane optical connectors <NUM>, arranged to engage with or mate with corresponding module power ports/connectors and module optical ports/connectors on a battery module. Each battery bay <NUM> is therefore provided with a backplane power connector <NUM> and a backplane optical connector <NUM> for engaging with a battery module inserted within the battery bay. Backplane power connectors <NUM> and backplane optical connectors <NUM> are movably coupled to backplane <NUM>, such that backplane power connectors <NUM> and backplane optical connectors <NUM> may move laterally slightly in the plane defined by backplane <NUM>.

Flexible busbars <NUM> are provided to interconnect two adjacent backplane power connectors <NUM> such that electrical power may flow from one backplane power connector <NUM> to another. Because of their flexibility, during engagement of a battery module <NUM> with backplane <NUM>, slight misalignment of battery module <NUM> will be corrected by the flexible busbars and the movable coupling of backplane power connectors <NUM> and backplane optical connectors <NUM> with backplane <NUM>, allowing slight movement of backplane power connectors <NUM> relative to the battery module <NUM>. The backplane power connector <NUM> at lower left is used to connect to a ship's DC bus. Backplane power connectors <NUM> and backplane optical connectors <NUM> are positioned proximate dividing wall <NUM>.

<FIG> shows rack assembly <NUM> in an empty configuration. That is, in <FIG> rack assembly <NUM> is shown without any battery modules installed. Battery module <NUM> such as that shown in <FIG> may be used with rack assembly <NUM>. Turning to <FIG>, there is shown an embodiment of a battery module <NUM> that may installed in rack assembly <NUM>. <FIG> shows a front view of battery module <NUM> and <FIG> shows a rear view of battery module <NUM>. Battery module <NUM> houses (though not a shown) a number of cells disposed in a stacked arrangement within an enclosure <NUM>. On the rear face of battery module <NUM> there are shown module optical communication ports <NUM>, module power ports <NUM> and exhaust seal <NUM>. Module optical communication ports <NUM> and module power ports <NUM> are comprised in a module power connector <NUM> (described in more detail below). Module optical communication ports <NUM> are positioned in a vertical alignment, as are module power ports <NUM>. Module optical communication ports <NUM> and module power ports <NUM> form part of a module power/communication connector, described in more detail below. On the underside of battery module <NUM> is provided a heat sink <NUM> comprising a finned arrangement for assisting heat dissipation away from battery module <NUM>.

In use, battery modules (such as battery module <NUM>) are installed in a rack assembly by sliding a battery module into a vacant battery bay of the rack assembly. A fully-filled rack assembly <NUM> is shown in <FIG>. Each battery bay <NUM> contains a battery module <NUM> inserted therein, each battery module being engaged with backplane <NUM>. To mount a battery module <NUM> into rack assembly <NUM>, battery module <NUM> is inserted rear face first into a vacant battery bay <NUM>. Battery module <NUM> is inserted fully into battery bay <NUM> until reaching a mating position, wherein in the mating position module optical ports <NUM> and module power ports <NUM> (of battery module <NUM>) blind matingly engage with corresponding ports in a backplane optical connector <NUM> and a backplane power connector <NUM> (of backplane <NUM>), and exhaust seal <NUM> (of battery module <NUM>) blind matingly engages with an exhaust port <NUM> (of backplane <NUM>). Guiding members <NUM> assist with proper alignment of the battery module <NUM>'s ports relative to the corresponding ports on backplane <NUM>.

As will be described in more detail below, alignment features provided on the module power/communication connector also assist in alignment of the battery module <NUM>'s ports relative to the corresponding ports on backplane <NUM>.

As mentioned above, engagement of module optical ports <NUM> with a backplane optical connector <NUM>, engagement of module power ports <NUM> with a backplane power connector <NUM>, and engagement of exhaust seal <NUM> with an exhaust port <NUM> comprises a blind mate engagement. As known in the art, a blind mate engagement may be any engagement where self-aligning features on the connectors allow for slight misalignment during coupling/engagement of one connector to another. The self-aligning features assist in proper alignment of the connectors to ensure a proper engagement of the connectors. Engagement of module optical ports <NUM> with a corresponding backplane optical connector <NUM> means that module optical ports <NUM> are brought into optically communicative proximity of corresponding ports in backplane optical connector <NUM>. With the blind mating described above, there is no need for a user to manually connect each battery module <NUM> to backplane <NUM>. The optical and electrical engagement of each battery module <NUM> with backplane <NUM> is assured by the proper alignment of optical/power connectors <NUM>/<NUM> with optical/power connectors <NUM>/<NUM>, and the proper alignment of exhaust seal <NUM> and exhaust port <NUM>, on both the rear face of battery module <NUM> and on backplane <NUM>.

Turning to <FIG>, there is shown in more detail a portion of module power/communication connector <NUM> in accordance with an embodiment of the disclosure. For clarity, module power/communication connector <NUM> will be referred to simply as module power connector <NUM>. Module power connector <NUM> is used with battery module <NUM> as described in connection with <FIG>, and is disposed on the rear side of battery module <NUM> (i.e. the side that engages with backplane <NUM>).

Module power connector <NUM> comprises optical communication ports <NUM> for optical communication with corresponding ports on a backplane power connector of backplane <NUM>, to which module power connector <NUM> is to be engaged. Module power connector <NUM> comprises thermistors <NUM> whose operation is described in more detail below. High Voltage Interlock Loop (HVIL) connections <NUM> extend from HVIL power ports <NUM> and, when module power connector <NUM> is engaged to backplane <NUM>, to a local HVIL jumper (not shown). The operation of the HVIL is discussed in more detail below. Adjacent HVIL power ports <NUM> is a bonding/ground connection <NUM> connected to bonding/ground port <NUM>. Adjacent HVIL and bonding/ground ports <NUM>, <NUM> are battery connection pass-throughs <NUM> allowing the main battery module contacts to engage with corresponding contacts in the corresponding backplane power connector <NUM>. Battery connection pass-throughs <NUM> form the outside of power ports <NUM> seen in <FIG>. In the embodiment shown in <FIG>, a blind mate interface PCB <NUM> is included. Blind mate interface PCB <NUM> provides a means of aggregating a number of signals, including those from HVIL connections <NUM> and thermistors <NUM>, and directing those signals to an interface PCB connector.

The backplane-facing side of module power connector <NUM> is shown in <FIG>. Surrounding battery connection pass-throughs <NUM> is a blind mate lead-in taper <NUM> allowing blind mate alignment of module power connector <NUM> with a corresponding backplane connector <NUM>.

Now turning to <FIG>, there is shown module power connector <NUM> being brought into engagement with corresponding backplane power connector <NUM>. <FIG> shows module power connector <NUM> and backplane power connector <NUM> in an unmated position, <FIG> shows module power connector <NUM> and backplane power connector <NUM> in an aligned position, <FIG> shows module power connector <NUM> and backplane power connector <NUM> in a power mated position, and <FIG> shows module power connector <NUM> and backplane power connector <NUM> in a fully mated position.

Module power connector <NUM> includes power sockets <NUM>, HVIL socket <NUM> and blind mate lead-in taper <NUM>. Backplane power connector <NUM> includes power pins <NUM> for insertion into power sockets <NUM>, and HVIL jumper pin <NUM> for insertion into HVIL socket <NUM>. During engagement of module power connector <NUM> with backplane power connector <NUM>, power pins <NUM> are self-aligned with power sockets <NUM> by virtue of blind mate lead-in taper <NUM> interacting with backplane power connector <NUM>. Flexible busbars <NUM> coupled to backplane power connector <NUM> may movably flex during engagement of module power connector <NUM> with backplane power connector <NUM>, thereby causing backplane power connector <NUM> to move relative to backplane <NUM> and assist with the alignment of backplane power connector <NUM> with module power connector <NUM>.

In <FIG>, power pins <NUM> are shown in electrical contact with power sockets <NUM>, and in <FIG> module power connector <NUM> and backplane power connector <NUM> are shown fully engaged or mated, with HVIL jumper <NUM> electrically coupled with HVIL socket <NUM>. During disengagement of module power connector <NUM> from backplane power connector <NUM>, HVIL jumper <NUM> disengages from HVIL socket <NUM> before power pins <NUM> disengage from power sockets <NUM>.

Turning to <FIG>, there is shown an optical engagement of module power connector <NUM> with backplane power connector <NUM>. Backplane power connector <NUM> includes optical fibres <NUM> terminating at optical lenses <NUM>. Module power connector <NUM> includes optical ports <NUM>, as well as opto-electronic components <NUM> in optical communication with optical fibres <NUM>. Electronic signals generated by a module controller on the battery module may be received at opto-electronic components <NUM>, converted into optical signals and transmitted to the pack controller via optical fibres <NUM>. A foam gasket <NUM> separates module power connector <NUM> from backplane power connector <NUM>.

The battery system of the present disclosure will now be described in use. In a high-voltage battery system (such as the one described in connection with <FIG>), the module and backplane power connectors are sometimes subject to overheating. As the module and backplane connectors are coupled in a blind mate engagement, the connectors are generally inaccessible and visual inspection of the connectors is usually not possible. Accordingly, the present disclosure provides for a system and method of determining whether the module and/or backplane connectors are overheating, as will be described below. Other risks to lithium ion batteries include overcharging, over-discharging, and high temperatures in general. To protect against such hazards, it is typical to implement a number of safety-disconnect features, again as will now be described in more detail below.

<FIG> is a circuit diagram of battery module <NUM>, according to an embodiment of the disclosure. Battery module <NUM> includes a number of serially connected cells <NUM>. Battery module <NUM> further includes a number of voltage sensors <NUM> connected to cells <NUM> and configured to read the voltage of each cell <NUM>. The outputs of voltage sensors <NUM> are directed to comparators <NUM>. The outputs of comparators <NUM> are connected to a logic block <NUM> that asserts its output if any of the outputs of comparators <NUM> is asserted. For example, logic block <NUM> may comprise one or more logical OR-gates and/or logical AND-gates. Battery module <NUM> further includes a temperature sensor <NUM> used to measure an ambient temperature of battery module <NUM>. For example, temperature sensor <NUM> may be positioned so as to monitor the temperature of one or more of cells <NUM>. Battery module <NUM> may include one or more further temperature sensors (not shown) for measuring the temperature at different locations within battery module <NUM>. The output of temperature sensor <NUM> is directed to comparator <NUM>, whose output in turn is fed to logic block <NUM>.

A thermistor <NUM> (for example one of thermistors <NUM> in <FIG>) is integrated within module power connector <NUM> (shown with dashed lines), which includes module terminals 64a and High Voltage Interlock Loop (HVIL) terminals 64b. Module power connector <NUM> may be the same as module power connector <NUM> described above, but for the purpose of <FIG> is labelled differently. Physically, thermistor <NUM> is electrically coupled to HVIL terminals 64b. Thermistor <NUM> is positioned to detect changes in temperature of module power connector <NUM>. As known in the art, the resistance of thermistor <NUM> will vary with the sensed temperature of module power connector <NUM>. Therefore, as the temperature of module power connector <NUM> varies, so too does the electrical resistance of thermistor <NUM>.

Thermistor <NUM> is connected to pull-down resistor <NUM>, together forming a voltage divider circuit. An analog-to-digital converter (ADC) <NUM> measures the voltage at the voltage divider circuit. The voltage measured by ADC <NUM> will vary as a function of the resistance at thermistor <NUM>, resulting in a voltage change measured by ADC <NUM>. A programmable logic device <NUM>, such as a microcontroller, is used to convert the voltage measured by ADC <NUM> into a temperature. The output of programmable logic device <NUM> is configured to communicate directly with a pack controller <NUM> (see <FIG>) over a battery management system communication link (not shown). In an alternative embodiment (as shown in <FIG>), the output of programmable logic device <NUM> may be configured to communicate with logic block <NUM>. Logic block <NUM> is configured to control a switching device <NUM>, such as a relay, a transistor, or an AND-gate, operable to alternately open or close a safety-disconnect loop <NUM>.

<FIG> is a circuit diagram of a number of battery modules <NUM> connected in series to pack controller <NUM> and switching device <NUM>. Safety-disconnect loop <NUM> comprises a continuous signal path that passes through all of battery modules <NUM> that are connected to pack controller <NUM>. If the switching device <NUM> of any battery module <NUM> interrupts (that is, opens) safety disconnect loop <NUM>, then pack controller <NUM> is configured to open switching device <NUM> thereby preventing further charging or discharging of battery modules <NUM>. Safety-disconnect loop <NUM> comprises an optical communication medium such as optical fibres (for example optical fibres <NUM> described above) that terminate at a module optical communication connector <NUM>. The optical signal carried by safety-disconnect loop <NUM> is converted to an electronic signal at an opto-electronic receiver <NUM>. The output of opto-electronic receiver <NUM> passes through switching device <NUM> and into opto-electronic transmitter <NUM> that is operable to convert the electric signal into an optical signal. Opto-electronic receiver <NUM> may be, for example, a photo-transistor or a photo-diode. Opto-electronic transmitter <NUM> may be, for example, a light-emitting diode or a laser.

Together, the above-described components embody a number of safety-disconnect features which can be used to interrupt the flow of power to/from battery module <NUM> should any one of a number of safety parameters not be met. In particular, during operation, the voltage across the battery pack terminals <NUM>, <NUM> can typically be up to <NUM> Volts. With such a high voltage, it would be dangerous to disconnect battery module <NUM> from the battery pack while the battery string (i.e. the remaining battery modules in the pack) remains connected to the main DC bus, because bus voltage would be exposed on the backplane connectors. Still further, as mentioned above, overheating of the module/backplane connectors, overcharging/over-discharging of the battery module, and high operating temperatures are all conditions under which it is unsafe to operate the battery module. To prevent such an unsafe occurrence, safety-disconnect loop <NUM> is used to automatically disconnect the battery system from the DC bus as soon as an unsafe condition is detected.

In order to avoid overheating of battery module <NUM> (for example in the case of a thermal runaway event, as known in the art), the output of temperature sensor <NUM> is compared to a preset temperature threshold in comparator <NUM>. Comparator <NUM> will output a digital signal to logic block <NUM> if the measured temperature is greater than the preset temperature threshold. The digital signal received at logic block <NUM> will trigger logic block <NUM> to operate switching device <NUM>, thereby opening safety-disconnect loop <NUM>.

Opening safety-disconnect loop <NUM> will cause pack controller <NUM> to determine a safety-disconnect condition has been met, and will result in pack controller <NUM> operating switching device <NUM> to disconnect battery module <NUM> from the DC bus. Thus, further overheating of battery module <NUM> may be prevented.

Similarly, in order to avoid overcharging/overdischarging of battery module <NUM>, the outputs of voltage sensors <NUM> are compared to preset voltage thresholds in comparators <NUM>. A comparator <NUM> will output a digital signal to logic block <NUM> if the voltage measured by its respective voltage sensor <NUM> is greater than the preset voltage threshold. The digital signal received at logic block <NUM> will trigger logic block <NUM> to operate switching device <NUM>, thereby opening safety-disconnect loop <NUM>. As described above, opening safety-disconnect loop <NUM> will result in pack controller <NUM> determining that a safety-disconnect condition has been met. In response, pack controller <NUM> will operate switching device <NUM> to interrupt power flow to/from battery module <NUM>, thereby preventing further overcharging/overdischarging. Comparators <NUM> are configured so that if the voltage of a cell <NUM> exceeds an allowable upper threshold (for example <NUM>. 20V for lithium ion NMC cells) then their output signal is asserted. Comparators <NUM> may also be configured so that if the voltage of a cell <NUM> falls below an allowable lower threshold (for example <NUM>. 70V for lithium ion NMC cells) then their output signal is asserted.

Safety-disconnect loop <NUM> is also used to interrupt power flow to/from battery module <NUM> in the event that battery module <NUM> is disconnected from the backplane. To implement this feature, a voltage supply <NUM> provides voltage to High Voltage Interlock Loop (HVIL) terminals 64b. When battery module <NUM> is engaged to the backplane, HVIL terminals 64b are connected to voltage supply <NUM> and the voltage is returned by an HVIL jumper <NUM>. Current then passes from voltage supply <NUM>, through HVIL jumper <NUM> and through thermistor <NUM> and pull-down resistor <NUM>. Thermistor <NUM> and pull-down resistor <NUM> form a voltage divider. The resistance value of pull-down resistor <NUM> is selected so that the voltage input at a comparator <NUM> is measurably above zero. When battery module <NUM> is disengaged from the backplane, HVIL terminals 64b disconnect from HVIL jumper <NUM> so that there is no current through the voltage divider, and pull-down resistor <NUM> holds the voltage at comparator <NUM> to be zero. Comparator <NUM> is designed so that a low voltage asserts the output to logic block <NUM> whereas a high voltage de-asserts the output. Thus, when battery module <NUM> is disengaged from the backplane, the voltage at comparator <NUM> is lowered (representing an "unsafe state") and a digital signal is sent to logic block <NUM>, triggering switching device <NUM> which results in interruption of power to/from battery module <NUM> as described above. Conversely, when battery module <NUM> is engaged with the backplane, the voltage input at comparator <NUM> is raised (representing a "safe state"), and comparator <NUM> no longer asserts an output to logic block <NUM>.

In order to detect overheating of module power connector <NUM>, safety-disconnect loop <NUM> may also be opened through the use of thermistor <NUM>. In particular, as described above, ADC <NUM> measures the voltage at the voltage divider circuit created by thermistor <NUM> and pull-down resistor <NUM>. Programmable logic device <NUM> converts the voltage measured by ADC <NUM> into a temperature which is compared to a preset temperature threshold stored within programmable logic device <NUM>. A digital output is asserted to logic block <NUM> if the measured temperature exceeds the preset temperature threshold. The temperature threshold may be set so as to ensure that the operation of module power connector <NUM> remains within a safe operational temperature range for the materials of which it (and other parts of the battery pack that are in thermal contact with it) is comprised. As a non-limiting example, a module connector composed in part of plastic may have a safe operational temperature below <NUM> degrees C, and the preset temperature threshold may therefore be set to <NUM> degrees C. Any other suitable temperature threshold is contemplated within the scope of this disclosure.

The digital signal received at logic block <NUM> will trigger logic block <NUM> to operate switching device <NUM>, thereby opening safety-disconnect loop <NUM>. As described above, opening safety-disconnect loop <NUM> will result in pack controller <NUM> determining that a safety-disconnect condition has been met. In response, pack controller <NUM> operates switching device <NUM> to disconnect the string of battery modules <NUM> from the DC bus. In particular, by operating switching device <NUM>, power flow to/from battery modules <NUM> via module terminals 64a is prevented. Thus, overheating of module power connector <NUM> may be prevented.

In an alternative embodiment, programmable logic device <NUM> transmits the temperature value via a battery management system communications link (not shown) directly to pack controller <NUM>, without going via safety-disconnect loop <NUM>. The communication will cause pack controller <NUM> to determine a safety-disconnect condition has been met, and will result in pack controller <NUM> operating switching device <NUM> to disconnect battery module <NUM> from the DC bus. Thus, further overheating of battery module <NUM> may be prevented. In this embodiment, there is no need to rely on programmable logic device <NUM> to determine whether the measured temperature exceeds the preset temperature threshold (programmable logic device <NUM> may comprise software which is generally more failure-prone than hardware comprised in pack controller <NUM>). Rather, the functionality of programmable logic device <NUM> may be carried out in pack controller <NUM>.

An alternative embodiment of battery module <NUM> is shown in <FIG>. In this embodiment, a pair of thermistors 66a and 66b are electrically coupled to module terminals 64a, as opposed to HVIL terminals 64b. The operation of the circuit of <FIG> is otherwise identical to that of <FIG>. However, rather than communicating directly with logic block <NUM>, as described above programmable device logic <NUM> transmits the temperature value received from either ADC 70a, 70b via a battery management system communications link (not shown) directly to pack controller <NUM> , without going via safety-disconnect loop <NUM>. Pack controller <NUM> then determines whether a safety-disconnect condition has been met.

In a further alternative embodiment (not shown), thermistor <NUM> may be integrated with HVIL jumper <NUM> comprised in the backplane power connector. In other words, thermistor <NUM> may be located on, within or otherwise within thermally conductive distance of the backplane power connector, and may be electrically coupled to HVIL jumper <NUM>. Thermistor <NUM> will therefore be responsive to changes in temperature of the backplane power connector, and will result in switching device <NUM> being operated should the temperature of the backplane power connector increase beyond a preset threshold, as described above.

It should be noted that battery module <NUM> of <FIG> forms part of a series connection of multiple battery modules <NUM> (such as shown in <FIG>). Furthermore, operation of switching device <NUM> will result in other battery modules <NUM> in the series string being disconnected from the DC bus. Thus, should one battery module experience a safety-critical issue (i.e. overheating/overvoltage etc.), then all battery modules in the series string will be disconnected from the DC bus.

Claim 1:
A battery system comprising:
a backplane (<NUM>) for engaging with one or more battery modules (<NUM>), the backplane comprising one or more backplane optical communication connectors;
one or more battery modules (<NUM>) each comprising a module optical communication connector (<NUM>), and each being configured to engage with the backplane by moving the battery module into engagement with the backplane such that the module optical communication connector engages with a corresponding backplane optical communication connector (<NUM>) in a blind mate engagement; and
one or more optical fibres (<NUM>) terminating at the one or more backplane optical communication connectors.