GB2607882A - Battery unit - Google Patents

Battery unit Download PDF

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Publication number
GB2607882A
GB2607882A GB2108368.8A GB202108368A GB2607882A GB 2607882 A GB2607882 A GB 2607882A GB 202108368 A GB202108368 A GB 202108368A GB 2607882 A GB2607882 A GB 2607882A
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GB
United Kingdom
Prior art keywords
cell
battery unit
battery
tab
tabs
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
GB2108368.8A
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GB202108368D0 (en
Inventor
David Lewis John
Brown Mark
Anne Self Valerie
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Amte Power Plc
Original Assignee
Amte Power Plc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Amte Power Plc filed Critical Amte Power Plc
Priority to GB2108368.8A priority Critical patent/GB2607882A/en
Publication of GB202108368D0 publication Critical patent/GB202108368D0/en
Priority to PCT/GB2022/051449 priority patent/WO2022258976A2/en
Publication of GB2607882A publication Critical patent/GB2607882A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
    • H01M10/4257—Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4285—Testing apparatus
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
    • H01M10/486—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte for measuring temperature
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/61—Types of temperature control
    • H01M10/613—Cooling or keeping cold
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/64—Heating or cooling; Temperature control characterised by the shape of the cells
    • H01M10/647—Prismatic or flat cells, e.g. pouch cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/65—Means for temperature control structurally associated with the cells
    • H01M10/655—Solid structures for heat exchange or heat conduction
    • H01M10/6556—Solid parts with flow channel passages or pipes for heat exchange
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/65—Means for temperature control structurally associated with the cells
    • H01M10/655—Solid structures for heat exchange or heat conduction
    • H01M10/6556—Solid parts with flow channel passages or pipes for heat exchange
    • H01M10/6557—Solid parts with flow channel passages or pipes for heat exchange arranged between the cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/65—Means for temperature control structurally associated with the cells
    • H01M10/656—Means for temperature control structurally associated with the cells characterised by the type of heat-exchange fluid
    • H01M10/6567—Liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/65—Means for temperature control structurally associated with the cells
    • H01M10/656—Means for temperature control structurally associated with the cells characterised by the type of heat-exchange fluid
    • H01M10/6567—Liquids
    • H01M10/6568—Liquids characterised by flow circuits, e.g. loops, located externally to the cells or cell casings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/202—Casings or frames around the primary casing of a single cell or a single battery
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/211—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for pouch cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/262—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders with fastening means, e.g. locks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/271—Lids or covers for the racks or secondary casings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/503—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the shape of the interconnectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/521—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the material
    • H01M50/522—Inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/521—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the material
    • H01M50/526—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the material having a layered structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
    • H01M2010/4271—Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
    • H01M2010/4278—Systems for data transfer from batteries, e.g. transfer of battery parameters to a controller, data transferred between battery controller and main controller

Abstract

A battery unit 10 comprises an electrochemical cell 11, which is preferably a pouch cell, a cell monitoring system associated with the cell, data storage means electrically connected to the cell monitoring system and adapted to store data received from the cell monitoring system, and an enclosure, e.g. a frame 20, configured and arranged to accommodate the cell monitoring system and data storage means, and to at least partially support the cell. The cell monitoring system and data storage means may be provided in a recess (21, Fig 2) within the frame. The battery unit may be designed to ensure that the cell is constrained to one particular orientation and position within the frame, in a predetermined configuration with respect to cell polarity, such as by using locating features 13,15 on the battery tabs 12,14. Means for efficiently connecting, cooling and applying a compressive force to the battery unit are also provided. A generic connecting device or busbar (Figs 9A-C & 20-28) that may be used for the electrical interconnection of individual cells within a battery module is also disclosed. The generic busbar facilitates formation of battery modules using different arrangements of electrically interconnected battery units comprising cells.

Description

Intellectual Property Office Application No GI32108368.8 RUM Date August 2022 The following terms are registered trade marks and should be read as such wherever they occur in this document: Dupont Kapton Intellectual Property Office is an operating name of the Patent Office www.gov.uk/ipo Battery Unit The present invention relates to the field of batteries for the storage and discharge of electrical energy. Particularly, though not exclusively, the invention relates to battery units incorporating pouch cells within a frame, wherein the frame has embedded functionality.
The frame may accommodate means for monitoring and recording electrical performance, temperature and health of the cells. The battery unit is designed to ensure that the cell is constrained to one particular orientation and position within the frame, in a predetermined configuration with respect to cell polarity. Locator keying features associated with the frame and the cell constrain the cell into this predetermined orientation. Means for efficiently connecting, cooling and applying a compressive force to the battery unit are also provided by the invention. The invention further provides a generic connecting device or busbar that may be used for the electrical interconnection of individual cells vvithin a battery module. The generic busbar facilitates formation of battery modules using different arrangements of electrically interconnected battery units comprising cells including battery sub-assemblies such as groups of parallel cells.
Batteries formed from pouch cells surrounded by a protective housing are known. Multiple individual cells are typically combined and interconnected to form a larger ba:tery module. Battery modules are provided with a mechanical support structure, tnermal interface and attached terminals for connection to external circuitry. Such battery modules are used in a wide field of applications each having differing requirements, with modules designed according to factors such as target voltage and current, available space and other application requirements including capacity, required charge and pulse/continuous discharge capability. However, each of these applications requires a tailored battery design and there is no standard industry format for creating a variety of battery configurations from common components.
The growing market for such battery units and modules demands ever higher performance and increased charging speed, Temperature of cells increases during both charge and discharge of cells. Quicker charging and discharging can lead to rapid overheating and issues with lithium plating causing safety concerns. Therefore, cell temperatures need to be monitored and controlled to prevent irreversible damage to a cell and ensure safe operating conditions. Typically, a battery management system is electrically coupled to cells within battery modules via a wiring harness. The battery management system is used to record and manage characteristics of cells within each module. However, the wiring harness adds practical complexity and weight to the battery modules.
Given the relatively high cost and environmental impact of producing such battery modules, it is desirable to reuse cells where possible. Currently, re-use of battery cells for second-life applications is not practical due to the difficulty associated with disassembly of battery modules, the requirement to match cell capacity to avoid balancing issues and the difference in the health/quality of individual used cells. During the operational lifetime of battery modules, individual cell performance is likely to be variable. [or example, following the primary use of each cell, cell capacity, which relates to the ability of a cell to store energy, may vary between different cells making up a battery, because the individual cells age at different rates during use within each battery module. Ideally, second lire battery modules require cells of similar cell capacity to form effective batteries. Thus, when battery modules are dismantled into individual cell units, there are practical and cost impediments to the re-use of individual cells for second life applications because cell capacity and health of individual cells is unknown, Again, the lack of industry standard battery formats also increases costs and inhibits reuse as each individual application uses bespoke technology.
Positive and negative contact 'tabs' extend from each cell and allow that cell to be connected as part of a circuit, Cell electrochemistry and the associated tab metallurgy determine the selection of materials for the external connectors (or busbars) based on the method of joining the tab to the busbar (such as via specific types of weld). For example, the electrochemistry of lithium-ion pouch cells require that the internal anode is connected to a copper tab and the internal cathode is connected to an aluminium tab.
Opposing ends of these copper and aluminium tabs extend outwardly from the cell for external electrical connection, If the free ends of the tabs are to be joined to the external connector via a fusion welding process (such as laser or resistance welding) tab metallurgy must be matched to the metallurgy of the external connectors or busbars to provide an effective electrical connection therebetvveen and avoid the risk of brittle intermetallic formations during the welding process. Depending on the desired capacity and voltage requirements of a battery module, there are many possible permutations and combinations of series or parallel stacking of cells making up a battery module. The need for busbars comprising both aluminium and copper sections, according to the respective tab positions for each particular arrangement of cells, means that individual module designs require bespoke busbar arrangements.
Current challenges faced in the design and manufacture of battery modules include: the need to provide solutions for different cell formats; the need for different cell interconnection arrangements to meet specific application requirements; the need for enhanced cell performance monitoring and thermal management; and the need to provide for re-use of batteries in second life applications.
In view of the foregoing, it is an object of the present invention to provide an improved battery that alleviates one or more of the aforementioned disadvantages associated with conventional batteries.
According to a first aspect of the invention there is provided a battery unit comprising: a cell for the storage and discharge of electrochemical energy; a cell monitoring system associated vvith the cell and adapted to monitor at least one characteristic of the cell; a data storage means electrically connected to the cell monitoring system and adapted to store at least a portion of the data received from the cell monitoring system; and an enclosure configured and arranged to accommodate the cell monitoring system, data storage means and at least partially support the cell.
Thus, the battery unit of the invention is a self-contained unit incorporating an electrochemical cell and an enclosure vvith embedded functionality and the means to measure and record cell characteristics.
Preferably, the cell is an electrochemical cell arranged for the charging, storing and discharging of electrochemical energy. Preferably, the cell comprises an anode and a cathode, with a separator and an electrolyte interposed between the anode and cathode. The cell may comprise a plurality of anodes and cathodes, each anode and cathode having a separator and electrolyte disposed therebetween, Thus the cell may comprise a stack of anodes and cathodes. Preferably, the cell comprises a pouch cell.
Preferably, the battery unit comprises contacts enabling electrical connection of the battery unit to an external electrical load. The contacts may extend outwith a volume defined by the enclosure. The cell may comprise contact tabs enabling interconnection of the cell with an external electrical load. The cell may comprise contact tabs extending from opposing ends of the cell. Alternatively, the cell may comprise two contact tabs extending from one side of the cell.
Preferably, the cell comprises a positive and a negative contact tab enabling the interconnection of the battery unit in an external circuit. Preferably, the contact tabs are electrically connected to the anode or the stack of electrodes that comprise the anode, and the cathode or the stack of electrodes that comprise the cathode, within the cell pouch. The contact tabs may extend outvvith a volume defined by the enclosure.
The cell may comprise a positive and a negative contact tab, wherein both tabs are adapted for electrical connection with a connecting device. The connecting device may be arranged and configured to provide a connection with at least one other battery unit. The connecting device may include an electric conductor for selectively connecting tabs.
The connecting device may be rigid or flexible. The connecting device may be a flexible connection including but not limited to: flexible cable, single core or multi-core cable, braids, or meshed cable. The connecting device may include a busbar. The busbar may comprise a rigid electrical connector to provide electrical connection between selected tabs.
One of the contact tabs may comprise a bimetallic strip. Where the cell electrolyte includes lithium ions, the bimetallic strip may be formed from copper and aluminium.
The bimetallic strip may be disposed such that a first end of the bimetallic strip formed from a first metal is in contact with either the cathode/cathode stack, or the anode/anode stack within the pouch cell, and a second end of the bimetallic strip formed from a second metal extends outvvardly from the cell.
A monometallic contact tab may be located in contact with the remaining electrode/electrode stack. The metallurgy of the monometallic tab may be selected according to the cell electrochemistry and the orientation of the bimetallic tab. The second tab may comprise copper or aluminium.
The metallurgy of the connecting device may be selected to match both the metallurgy of the monometallic tab and the second end of the bimetallic tab. Preferably, the metal from which the monometallic tab is formed and the metal from which the outwardly extending second end of the bimetallic strip is formed is the same metal from which the connecting device is formed. For a lithium-ion cell, the metal may comprise either copper or aluminium.
The cell monitoring system may include at least one sensor element to monitor at least one characteristic associated with the cell, The cell monitoring system may include a plurality of sensor elements that measure characteristics associated with the cell including but not limited to: current, voltage and/or temperature.
The cell monitoring system may include voltage and temperature sensors associated with each cell. The cell monitoring system may comprise at least two sensors electrically connected to the data storage means within the enclosure of the cell. The cell monitoring system may comprise a plurality of sensors in the form of sensing elements electrically connected to a processing device in the form of a multiplex semiconductor device or chip.
The cell monitoring system may comprise at least one temperature sensor located proximate or on the surface of the cell, The cell monitoring system may comprise a plurality of temperature sensors spaced at intervals along the surface of the cell. Each temperature sensor may be connected to the data storage means.
The temperature sensors may be selected from the group including but not limited to: thermistors, thermocouples, optical sensors and infra-red sensors, The data storage means may comprise a data processor and the data processor may be programmed to sequence temperature monitoring from each temperature sensor at discrete intervals. The data processor may compare values from each temperature sensor and record deviations in temperature above certain predetermined values for each sensor, Alternatively, the data processor may provide an average value of cell temperature from the temperature sensors, Provision of a plurality of temperature sensors may advantageously provide redundancy, such that failure of a single sensor element does not inhibit recordal of data on the health of the cell. Further, where data is collected from individual temperature sensors, monitoring the temperature in multiple positions can be helpful to identify any thermal gradient along the length of the cell as well as recognise local hot spots which may be indicative of malfunction within the cell.
The cell monitoring system may also be arranged to provide an electrical connection between the tabs of the cell and the data storage means for the measurement and/or recordal of any one or more of the following characteristics: temperature, resistance, voltage and/or current. A data processor associated with the data storage means may be arranged to record voltages that are outwit a predetermined acceptable range.
The data storage means may comprise electronic circuitry and components arranged to record, process and store data relating to the health of the cell from the cell monitoring system.The data storage means may comprise a semiconductor device to receive cell temperature measurements and cell voltage measurements form the cell monitoring system.
The cell monitoring system and/or the data storage means may be in electrical communication with an external battery management system. The battery management system may be arranged to receive data regarding cell characteristics, process said data and provide output commands to ensure cells remain within safe operational parameters. For example, the battery management system may monitor and manage cells within a battery pack throughout their lifetime by reacting to input data concerning cell characteristics and providing outputs that balance cell parameters.
The data storage means may comprise a wireless device, The semiconductor device may include a microprocessor and a transmitter for the wireless communication of data.
The battery unit may be provided with means for transmitting information from the data storage means. The battery unit may comprise external electrical contacts electrically connected to the data storage means enabling electrical interconnection of the data storage means with an external electrical device for transmitting information regarding cell characteristics from the data storage means. During use of the cell, the external electrical contacts may be used for electrical interconnection with a battery management system. Following use of a cell, a device may be 'plugged' into the data storage means via the external electrical contact for a wired connection to access and recover stored data from the battery unit.
Alternatively, or additionally, the battery unit may further comprise a contactless data transmitter electrically connected to the data storage means and arranged for the contactless transmission of data from the battery unit. The contactless data transmitter may comprise a radio frequency transmitter. The radio frequency transmitter may also comprise a unique identifier such that each battery unit and its cell characteristics are individually identifiable using a remote device.
Thus, the cell monitoring system can monitor characteristics relating to the health and function of the cell. Such data may be communicated to the battery management system when the cells are in use. During normal operation of the cells the data may be processed and utilised by the battery management system for variation of cell output within the battery units. The battery management system receives input data from the sensors associated with the cells, processes the data and provides output signals to the cells and other external devices, such as cooling systems, safety systems, communication systems and the like.
The data is also recorded and/or stored in the data storage means to enable the recorcial and retrieval of data either remotely or via a wired connection to provide useful information on the health and characteristics of the cell. Following use of the battery units the data may be used for establishing the state of health and capacity of individual cells to facilitate second life applications of the battery units.
The enclosure may comprise a protective frame arranged to substantially protect the enclosed cell. The enclosure may comprise a rigid frame arranged to support the edges of the cell. The enclosure may be made from plastic.
Advantageously, the enclosure may provide mechanical support and protection for the enclosed cell, thereby minimising vulnerability to damage during shipping, installation and use, The enclosure may be substantially rectilinear in shape. The enclosure may be in the form of a cassette frame. The enclosure may define a hollow internal receiving space for accommodating the cell.
The cell monitoring system, electrical contacts and/or data storage means may be at least partially embedded within the enclosure.
S
The enclosure may comprise at least one recessed aperture for accommodating the data storage means. The enclosure may comprise at least one recessed feature for accommodating at least part of the cell monitoring system. The enclosure may comprise at least one recessed channel for accommodating the electrical connectors, The recessed features may be moulded into the enclosure.
Preferably, the cell monitoring system and the data storage means are electrically connected by electrical connectors embedded or integrated within the enclosure. The electrical connectors may comprise discrete wires and/or flexible printed circuit board located in recessed channels. Alternatively, the electrical connectors may be moulded into the enclosure and formed by leadframe overmoulding, whereby the leadframe may be formed by photo-etching and/or stamping.
The data storage means and electrical connectors may be encapsulated in a protective material. The protective material may be selected to provide mechanical and environmental protection. The protective material may comprise any suitable electrically insulating encapsulation material including but not limited to: epoxy or silicone resin, urethanes and acrylics Inclusion of the cell monitoring system, data storage means and electrical connectors within the enclosure or cell frame advantageously facilitates optimal positional placement of the sensors on the surface of the cell and improves system reliability by reducing interconnection complexity. As a result of the arrangement and construction of the electrical connectors within the enclosure, the electrical connections are sufficiently durable to withstand variable operational environments.
The battery unit may comprise a compression member, The compression member may have a planar surface that substantially corresponds to a planar surface of the cell, The compression member may be accommodated alongside the cell, such that a planar face of the cell contacts a corresponding planar face of the compression mem her. The compression member may be accommodated within the assembled battery unit in a compressed configuration in which a known compression pressure is exerted on the cell.
The compression member may comprise a resiliently deformable material. The compression member may comprise a foam pad.
Dimensions of the enclosure may be selected to accommodate the cell and the compression member in a compressed configuration when the battery unit is assembled such that the cell is compressed by a known force. Thus, means of applying a known compression may be achieved by force deflection due to the geometry of the enclosure relative to the dimensions and force deflection of the compression member, Thus, the enclosure and compression member may protect the cell, the cell monitoring system and the data storage means from mechanical shocks and impacts as well as maximising service life of the cell by preventing internal separation of electrode layers.
The battery unit may comprise a heat transfer member that is located alongside at least a portion of a planar face of the cell. The heat transfer member may be electrically isolated from the cell and arranged to transfer excess heat away from the cell.
The heat transfer member may comprise a heat transfer plate made from a thermally conductive material. The heat transfer plate may also act as a backing plate for the battery unit, The heat transfer member may further comprise a channel allowing the circulation of a coolant fluid within the channel in use.
The battery unit may comprise locator keys associated with the enclosure and the cell tabs, wherein the locator keys constrain the cell to a preselected orientation and position with respect to the enclosure. The locator keys may include complementary features located on the cell and the enclosure to constrain orientation of the cell within the enclosure to a particular configuration.
The locator keys may comprise at least one locator member associated with the enclosure and a corresponding receiving aperture associated with the cell. The locator keys may comprise unique moulded features provided on the enclosure, each moulded feature having a corresponding receiving aperture located on the respective cell tab, such that the cell is constrained to the preselected orientat on within the enclosure to ensure correct assembly of the battery unit. The locator keys may further comprise visual identifiers of the correct orientation, for example, the components may be appropriately marked enabling visual assistance to achieve the correct assembly.
The battery unit may comprise two tab retainers, wherein each tab retainer is engageable with the enclosure in one position such that the tab retainers are constrained to fit over only one particular tab. The tab retainers may comprise a visual identification of polarity such that each tab retainer, which is only engageable with the enclosure over one preselected tab, thereby provides a reliable visual identification of tab polarity.
According to a second aspect of the invention there is provided a battery module comprising a plurality of interconnected battery units according to the first aspect of the invention Thus, the battery module comprises battery units that each have an associated cell monitoring system and data storage means for monitoring and recording information regarding the health of each individual battery unit making up the battery module. Therefore, the invention allows cells making up a larger module to have measurable and recordable data regarding cell characteristics including but not limited to temperature, resistance, current and/or voltage.
The battery module also provides means of communication of data to an external battery management system. The battery module may comprise terminals for electrical connection of the battery module to external circuitry. The battery module may be connectable to a battery management system for the control and monitoring of data recorded by the cell monitoring system. Thus, the battery management system may serve to provide comprehensive monitoring of cell state of charge and health. The arrangement is advantageous compared with a conventional arrangement whereby individual sensors would need to be mounted on each cell and physically interconnected to the battery management system by means of wires, thereby adding weight, cost and complexity to the battery module. By connecting sensors to the data storage means within the enclosure, characteristics of cells can be communicated sequentially to the battery management system thereby simplifying the wiring system, reducing cost and weight, and improving reliability.
The data storage means within each enclosure of the battery units making up a module also has significant advantages for assessing the state of health of used cells so that they may be appropriately reused for second life applications. Thus, the present invention presents significant opportunities for the optimised reuse of individual battery units.
The battery module may comprise connecting devices to connect tabs of the battery units in any required configuration. The connecting devices may electrically connect selected tabs of adjacent battery units, wherein battery units are arranged such that the polarity of adjacent cell tabs is in a preselected orientation and a plurality of connecting devices of a required length are electrically connected to the tabs in the requisite orientation.
The connecting device may comprised substantially planar sheet of metal. The substantially planar sheet may comprise a plurality of elongate slots arranged to receive cell tabs.
The connecting device may comprise locator holes, to facilitate visual confirmation of the location of the connecting device relative to cell tabs. The locator holes may serve a dual purpose of enabling improved access for welding of the tabs to the connecting device.
Alternatively, the connecting device may have a corrugated form, wherein cell tabs are accommodated in loops of the connecting device. The corrugated form may comprise uniform loops having a pattern of parallel ridges and grooves. Ridges may be provided with elongate slots for receiving cell tabs. Tabs may be pinched into contact with the connecting device within the tab receiving slot.
Alternate loops of the connecting device may be arranged to receive tabs, and tabs may be pinched into contact with the connecting device within the tab receiving slot allowing at least partial deformation of intermediate loops within the corrugated form to facilitate the pinched contact between the tab and the connecting device, The connecting device may include a base portion having abutments that are substantially perpendicular to the base portion, wherein the abutments are avanged for substantially parallel contact vvith the cell tabs, The connecting device may comprise several separate parts that may be assembled to form parallel abutments on each side of the cell tabs. The connecting device may comprise U-shaped and/or J-shaped parts, The connecting device may be welded to the tabs allowing the electrical interconnection of the selected cells between battery units within the module. The connecting device may be laser welded to the tabs. Thus, the interface between the connecting device and the tab may be welded to ensure optimum contact.
The connecting device may be formed from a single metal. The metal from which the connecting device may be formed is selected according to the metal from which the tabs are formed. The connecting device may comprise aluminium or copper.
The connecting device may comprised busbar.
The battery module may comprise at least one protective cover to substantial y protect portions of the battery units such as the tabs and connecting device. Preferably, the at least one protective cover substantially restricts damage to the connecting devices and the electrical connections of the module to restrict short circuit or injury through accidental contact.
The battery module may comprise a module cooling arrangement to substantially restrict overheating of the module in use.The module cooling arrangement may comprise at least one cooling plate that interfaces vvith the thermal transfer member of each battery unit.
The module cooling plates may comprise a channel allowing the circulation of a coolant within the channel in use. The, or each, cooling plate may act as a backing plate for the battery module. Thus, the cooling plate may have the dual function of a structural backing plate as well as a means for reducing the likelihood of cell overheating.
The battery module may further comprise structural support for supporting the plurality of interconnected battery units.
The battery module may comprise a compression mechanism for applying a compressive force to stacked battery units within the module. The compression mechanism may comprise mechanical compression means including but not limited to: straps with a tensioning mechanism; threaded studs; securing bar, band or clip, and/or securing bolts extending the length of the module.
Advantageously, the battery management system enables variation of the cell output within the battery unit via the data processor associated with the data storage means. Should monitoring of the cell health by the cell monitoring system indicate a problem with a cell, the battery management system can control certain cell functions to assist uniformity of voltage and temperature.
According to a third aspect of the invention there is provided a structure comprising one or more battery units according to the first aspect of the invention for stationary applications.
According to a fourth aspect of the invention there is provided a structure comprising one or more battery modules according to the second aspect of the invention for stationary applications.
The structure may comprise any entity incorporating a power system electrically connectable to the one or more of the battery units or modules for stationary applications.
The structure or entity may be selected from the group including but not limited to: buildings of any size, temporary or permanent structures, energy storage facilities, bunkers, caves, towers or offshore platforms.
According to a fifth aspect of the invention there is provided a movable entity comprising one or more battery units according to the first aspect of the invention for mobile applications.
According to a sixth aspect of the invention there is provided a movable entity comprising one or more battery modules according to the second aspect of the invention for mobile applications.
For mobile applications, the movable entity may include any mode of transport or vehicle including but not limited to, cars, vans, lorries, light and heavy goods vehicles, buses, any vvheeled vehicle, trams, trains, boats, movable buoyant structures, remotely-operated vehicles, aircraft, other flying machines. Thus, the batteries in the pack may provide auxiliary power and/or motive power for mobile applications.
According to a seventh aspect of the invention there is provided an enclosure for a pouch cell, the enclosure comprising a rigid frame for at least partially supporting edges of a pouch cell in use, wherein the enclosure comprises a moulded compartment for accommodating a data storage means and wherein the enclosure is arranged to receive or contain embedded electrical connectors linking the moulded compartment with at least one outlet that leads towards a cell in use.
The enclosure may comprise moulded channels for accommodating electrica connectors to connect at least one sensing element associated with a cell in use, with the moulded compartment for accommodating the data storage means in use, Alternatively, or additionally, the enclosure may include electrical connectors embedded within the enclosure and exposed at required locations. Formation of the electrical connectors can be achieved by leadframe overmoulding.
The enclosure may further comprise a pouch cell to form a battery unit. The enclosure may be moulded at least partially surrounding and connecting the cell, data storage means and electrical connectors to form an integrally moulded battery unit.
According to an eighth aspect of the invention there is provided a pouch cell comprising: at least one anode, at least one cathode, with a separator and an electrolyte disposed between each anode and cathode, an outer pouch sealed around the anode(s), cathode(s), electrolyte and separator(s), two tabs extending outwardly from the pouch and in internal electrical contact with the anode(s) and the cathode(s), wherein one tab comprises a bimetallic strip having first and second metals at respective ends of the bimetallic strip, and wherein the other tab is monometallic and is formed from the first metal; and wherein the outvvardly extending portion of each tab comprises the first metal and therefore the metals of each cell tab in contact with the internal anode(s) and the internal cathode(s) within the pouch are different.
Thus, one tab is formed from a bimetallic strip and the other tab is formed form a single metal selected according to the cell chemistry and metallurgy of the internal anode(s) and cathode(s), The pouch may be made of a polymer. Each tab may be glued into the pouch and heat sealed in position. Adhesive may be added to each tab in a centrally disposed location. The adhesive may be applied to each tab in a central region. For the bimetallic strip, the adhesive may be applied at the interface between the two metals. The adhesive may comprise a strip of glue. The adhesive may comprise modified polypropylene.
The two metals of the bimetallic strip may be bonded by a diffusion bond. The diffusion bond between the two metals may be achieved by cold rolling the two metals. Optionally, following the cold rolling process the bimetallic strip may be annealed.
The bimetallic strip may comprise copper and aluminium. The copper may be plated with tin or nickel to prevent corrosion.
Where the electrolyte within the cell comprises lithium ions, copper may be used for the internal contact of the negative tab and aluminium may be used for internal contact of the positive tab,The outwardly extending part of each tab may comprise the same metal.
The cell tabs may extend from the cell at opposing ends of the pouch. Alternatively, the cell tabs may extend from the cell from the same side of the pouch. Selection of cell construction and materials can be application specific.
At least one of the tabs may comprise a locator key cooperable with a corresponding locator key feature on an enclosure for supporting the tab to ensure that the tab is correctly oriented and positioned within an enclosure or cassette frame in use. The locator key on the tab may comprise a receiving aperture that is adapted to engage with a corresponding moulded feature provided in an enclosure.
According to a ninth aspect of the present invention, there is provided a battery unit comprising: a cell for the storage and discharge of electrochemical energy, wherein the cell comprises a positive tab and a negative tab, both tabs arranged for external electrical connection; an enclosure for receiving and at least partially supporting edges of the cell; and a cell orientation system associated with at least one of the cell and/or the enclosure, wherein the cell orientation system is arranged to orient the cell vvi:hin the enclosure such that the cell tabs extend in a predetermined orientation relative to the enclosure.
Thus, the invention ensures that the positive and negative tabs of the cell are correctly oriented and positioned within the enclosure to ensure correct polarity of the battery unit.
The cell orientation system may be configured such that assembly of the components of the battery unit is only possible with correct orientation of the cell with respect to cell polarity within the enclosure. Thus, the cell orientation system may be arranged such that it is not possible to assemble the battery unit until the cell is in the correct predetermined orientation relative to the enclosure, The cell may be substantially rectilinear in shape. The cell may comprise at least one anode and cathode, each anode and cathode separated by an electrolyte and a separator. The cell may comprise an outer sealed polymer bag.The cell may be a pouch cell.
The tabs may be terminals for the cell and extend outvvith the area defined by the outer sealed polymer bag of the pouch cell. The tabs may extend from the cell at opposing ends of the cell. Alternatively, the tabs may extend from the same side of the cell.
The enclosure may comprise a frame. The enclosure may be a cassette frame.
The cell orientation system may comprise locator keys provided on at least one of the cell and/or the enclosure, wherein the locator keys constrain the cell to the predetermined orientation within the enclosure. Cooperable locator keys may be provided on both the cell and the enclosure. The locator keys may comprise a profiled feature and a complementary recess or receiving aperture.
Each cell tab may be provided with a receiving aperture that is cooperable vvith a complementary locator member provided on the enclosure such that the receiving aperture cooperates with the complementary associated locator member on the enclosure.
Each tab may comprise a receiving aperture with a unique shape depending on the polarity of the tab and the enclosure may comprise an associated complementary moulded locator feature arranged for complementary cooperation with the corresponding receiving aperture. In this way the cells are constrained to orient with respect to unique locating keys such that the cells are accommodated correctly in the enclosure with respect to the predetermined polarity, The cell orientation system may be incorporated into relative tab position. For example, each tab and/or locator key may extend from the cell at a predetermined position relative to a centre line of the cell. Thus, the predetermined location of the keys may dictate the permitted orientation of the cell within the enclosure.
Locator keys may comprise a standard receiving aperture within each tab and a complementary profiled keying feature located on enclosure, wherein each corresponding profiled keying feature may each be spaced a different mismatched predetermined distance from the centreline of the cell.
The receiving apertures may be punched into the tabs during the manufacturing process and the profiled keying features may be pre-moulded into the enclosure.
Alternatively, or additionally, the cell orientation system may comprise a visual polarity identifier to provide a visual reference for correct cell orientation within the enclosure.
The incorporation of a cell orientation system into the battery unit ensures that the cell is oriented correctly within the enclosure according to polarity and eliminates the risk of assembly error, since the cell and tabs will not fit within the battery unit unless they are received in the permitted predetermined orientation in the enclosure.
The battery unit may further comprise a polarity identification system arranged to identify the polarity of each tab extending outwith the battery unit The polarity identification system may be arranged and configured such that assembly of the components of the battery unit is only possible vvith the polarity identification system in the predetermined position.
The polarity identification system may comprise a visual identifier to reflect the polarity of each tab of the battery unit. The visual identifier may include contrasting colours to reflect the polarity of each tab.
The battery unit may further comprise tab retainers for retaining the tabs. The tab retainers may comprise an elongate slot for receiving a tab and may be arranged to engage with the enclosure.
The tab retainers may also comprise the polarity identification system. Thus, the tab retainers may include dual functionality of retaining the tabs and identifying the polarity of the tab which they retain.
At least a portion of the polarity identification system may be associated with the enclosure. The enclosure may comprise an engaging feature moulded in a region surrounding each tab for receiving an inter-engaging feature of the tab retainer. Thus, the tab retainers may be designed with complementary interconnections such that they will only fit into their correct respective locations within the enclosure.
The battery unit may comprise two tab retainers, one for engaging a positive tab and another for engaging the negative tab, wherein each tab retainer comprises a visual identifier, The visual identifiers may include fuming the retaining tabs with contrasting colours, marking or othervvise providing a visual reference on each of the tab retainers.
Thus, visual and immediate identification of cell polarity may be achieved by providing colour coded tab retainers, for example red denoting positive tabs and black denoting negative tabs.
The battery unit may comprise an alignment feature to ensure that the battery unit may be aligned in a predetermined configuration with respect to adjacent battery units when assembled into a module. One side of the battery unit may comprise an interconnecting feature and the opposing side of the battery unit may comprise a corresponding complementary interconnecting feature.
The alignment feature may comprised tapered dowel on one leading face of the battery unit and a complementary dowel receiving recess on an opposing face of the battery unit.
The alignment features may be located in at least one corner of the unit. Preferably, the alignment features are located in the region of the four corners of the battery unit.
The alignment features may be incorporated in the enclosure. The alignment seatures may be moulded into the enclosure.
The alignment features are advantageous since they allow battery units to be conveniently stacked and correctly located in relation to one another to form a battery module comprising a plurality of battery units. The complementary dowel and hole features located on opposing faces at the corner of each unit provide positive and accurate location of battery units relative to one another.
The alignment features may be uniform and equidistant from each corner such that the battery unit may be stacked in different oriemations relative to one another depending on the desired interconnections and requirements of a battery module composed of the individual battery units.
The battery unit may further comprise a cell monitoring system. The cell monitoring system may include at least one device for measuring a characteristic of the cell. The cell monitoring system may comprise at least one sensing element for measuring a characteristic selected from the group including but not limited to: voltage, current, resistance and/or temperature The battery unit may further comprise a data storage means electrically connected to the cell monitoring system.
The cell monitoring system may comprise at least one sensor and electrical conductors connecting the at least one sensor to a data storage means. At least a portion of the cell monitoring system, the electrical connectors and the data storage means may be embedded within the enclosure. Thus, the battery unit may advantageously provide a self-contained unit for the measurement and storage of data regarding the state cf charge and health of the cell and for transmission of this data to an external battery management system.
The battery unit may comprise a compression member arranged to exert a compressive force on the cell.The battery unit may comprise a compression member selected to exert a substantially even pressure along a face of the cell. The dimensions of the enclosure may be predetermined such that the compression member is compressible to a known degree when the battery unit is in an assembled configuration and therefore exerts a known compressive force on the cell.
The battery unit may comprise a heat transfer member arranged to absorb heat from the cell. The heat transfer member may comprise a thermally conductive plate. The heat transfer member may be connectable to an external source to conduct excess heat away from the cell! The heat transfer member may comprise a thermally conductive, but electrically insulating material. The heat transfer member may comprise a cooling mechanism. The heat transfer member may include channels enabling circulation of a fluid coolant in use.
Thus, the cell temperature may be controlled to minimise the chance of inadvertent overheating of the cell during use.
According to a tenth aspect of the invention, there is provided a battery module comprising a plurality of interconnected battery units according to the ninth aspect of the invention The battery module may comprise a plurality of connecting devices to connect tabs of the battery units in the required configuration. The connecting devices may electrically connect selected tabs of adjacent battery units, wherein battery units are arranged such that the polarity of adjacent cell tabs is in a preselected orientation and the connecting devices of a required length are electrically connected to the tabs in the requisite orientation.
Each connecting device may have a corrugated form, wherein cell tabs are accommodated in alternate loops of the connecting device. The corrugated form may comprise uniform loops having a series of parallel ridges and grooves. At least one of alternate parallel ridges or grooves may be adapted to accept cell tabs. Preferably, alternate ridges are providing with elongate tab receiving slots.
Alternate loops of the connecting device may be provided with tab receiving slots, and tabs may be pinched into contact with the connecting device within the tab receiving slot, wherein at least partial deformation of the corrugated form enables the pinched contact between the tab and the connecting element.
The connecting device may be welded to the tabs allowing the interconnection of the selected cells between battery units within the module. Thus, the interface between the connecting device and the tab may be welded to ensure optimum contact. The tab and the connecting device may be laser welded to form a join therebetween, The connecting device may comprise a busbar.
The battery module may comprise at least one protective cover to substantial y protect portions of the battery units such as the tabs and connecting device. Preferably, the at least one protective cover substantially restricts damage to the connecting devices and the electrical connections of the module to restrict short circuit or injury through accidental contact.
The battery module may comprise a thermally conductive interface to conduct heat away from the battery units as required in use. The thermally conductive interface may comprise at least one cooling plate. The cooling plate may comprise a thermally conductive material. The thermally conductive interface may comprise a cooling plate having channels to accept a fluid coolant for heat exchange during use.
The thermally conductive interface may comprise a thermally conductive plate with a core adapted for the circulation of coolant fluid. The thermally conductive plate may also act as a structural and/or protective plate to increase functionality. The thermally conductive plate may comprise aluminium.
Advantageously, the thermally conductive interface provides an arrangement for cell cooling to substantially restrict the potential overheating of a cell during use.
The battery module may comprise at least one mechanical compression member for Holding the plurality of battery units in adjacent relation with a compressive force. The mechanical compression member may include securing straps, threaded studs and/or bolts to urge compression of the battery module.
The battery module may be electrically connected to a control system such as a battery management system. The individual self-contained battery units support first and second life applications since each cell and associated monitoring and data storage means is retained within the enclosure during subsequent disassembly of the module and re-use of the battery unit.
According to an eleventh aspect of the invention there is provided a structure comprising one or more battery units according to the ninth aspect of the invention for stationary applications.
According to a tvvelfth aspect of the invention there is provided a structure comprising one or more battery modules according to the tenth aspect of the invention for stationary applications.
According to a thirteenth aspect of the invemion there is provided a movable entity comprising one or more battery units according to the ninth aspect of the invention for mobile applications, According to a fourteenth aspect of the invention there is provided a movable entity comprising one or more battery modules according to the tenth aspect of the invention for mobile applications.
According to a fifteenth aspect of the invention, there is provided a battery unit for exerting a known compressive force on a cell, the battery unit comprising: a cell for the storage and discharge of electrochemical energy; an enclosure configured and arranged to support and at least partially enclose the cell; and a resilient member arranged to at least partially abut one face of the cell, wherein the dimensions of the enclosure are predetermined to accommodate the cell and part of the resilient member, such that assembly of the battery unit results in compression of the resilient member to exert a predetermined force on the cell.
The dimensions of the enclosure may be preselected to ensure that the enclosure provides a means of exerting controlled compression via the resilient member on the enclosed cell.
Thus, prior to assembly of the battery unit, the thickness of the resilient member extends beyond an area defined by the enclosure in a compliant direction such that assembly of the battery unit compresses the resilient member to fit within a volume defined by the enclosure.
A contact face of the resilient member that abuts the cell may have comparable dimensions to a planar face of the cell which 't abuts. The resilient member may have a similar width and length to the cell and the depth of the resilient member may be preselected according to the dimensions of the enclosure and the desired compressive force.
The invention is advantageous since it allows a cell within the enclosure, such as a pouch cell to be maintained under controlled uniform compression, thereby maximising service life by substantially restricting separation of electrode layers within the cell which may otherwise result in loss of energy capacity over time.
The resilient member may have a known linear resilience such that the compressive force is known based on the dimensions of the enclosure and width of the resilient member.
Preferably, the resilient member has a low compression set arid known compression force deflection characteristics. Therefore, the resilient member should be selected to resiliently rather than permanently deform when maintained under compression. H adcition, known deflection as a result of resilient member compression enables calculation of the resultant compressive force on the face of the cell.
The preselected compressive force may be adapted and tailored to an application by modifying one or more of the following: dimensions of the enclosure, thickness of the resilient material and/or inherent compression force deflection characteristics of the resilient member. Thus, the specific requirements for an applied compressive force according to cell type or application can be managed by adjusting one of several characteristics.
The resilient member may comprise a foam pad. The resilient member may comprise a polyurethane foam.
According to a sixteenth aspect of the invention, there is provided a battery module comprising a plurality of interconnected battery units according to the fifteerrh aspect of the invention.
According to a seventeenth aspect of the invention there is provided a battery module comprising: a plurality of battery units in adjacent relation, wherein each battery unit comprises a lithium ion cell and has electrical contact tabs extending therefrom in two d'screte rows enabling electrical interconnection of the battery units; and a plurality of monometallic connecting devices for electrically connecting selected tabs of the battery units.
The connecting device may comprise a monometallic connecting device. The metal selected for the connecting device may be matched with the metal of an outwardly extending part of the cell tabs. The connecting device may be formed from copper or aluminium.
Thus, for lithium-ion cells, the bimetallic cell tab enables the internal connection to the anode and cathode electrodes to be copper and aluminium respectively, while the external outwardly extending portion of both cell tabs can comprise aluminium thereby enabling interconnection between battery units using a monometallic connecting device. This arrangement makes interconnection of battery units simpler and cheaper. There is no requirement to match tabs to similar metals in the connecting device. Therefore, manufacture and interconnection using the connecting device of the seventeenth aspect of the invention is simplified and less expensive.
According to an eighteenth aspect of the invention there is provided a battery module comprising: a plurality of battery units in adjacent relation, wherein each battery unit has electrical contact tabs extending therefrom in tvvo discrete rows enabling electrical interconnection of the battery units; and a plurality of connecting devices, each connecting device comprising elongate slots spaced and arranged for receiving selected electrical contact tabs.
Advantageously, the elongate slots for receiving cell contact tabs allow visual verification of the seating of electrical contact tabs of the battery unit in the connecting device to ensure a good electrical connection therebetween.
The connecting device may comprise a substantially planar sheet comprising a plurality of elongate slots spaced and arranged to receive electrical contact tabs.
The connecting device may comprise locator holes, to facilitate location of the connecting device relative to electrical contact tabs. The locator holes may serve a dual purpose of enabling improved access for welding of the tabs to the connecting device.
The connecting device may comprise a sheet having a plurality of eguispaced parallel ridges, with elongate tab receiving slots located in the apex of each ridge. Electrical contact tabs received within tab receiving slots located in the ridges of the connecting device may be pinched into contact with the connecting device. The act of pinching the connecting device around the tabs may cause at least partial displacement of the tabs and the connecting device, thereby urging connected tabs towards one another. This may be advantageous in electrical isolation of one group of interconnected tabs from another.
Alternatively, the connecting device may have a corrugated form, vvherein electrical contact tabs are accommodated in loops of the connecting device, The corrugated form may comprise uniform loops having a pattern of parallel ridges and grooves. Elongate slots may be provided in the ridges of the corrugated form for receiving the electrical contact tabs.
Alternate loops of the connecting device may be arranged to receive electrical contact tabs, and tabs may be pinched into contact with the connecting device within the tab receiving slot allowing at least partial deformation of intermediate loops vvithin the corrugated form to facilitate the pinched contact between the tab and the connecting device.
The connecting device may include a body portion having tab abutments that are substantially perpendicular to the body portion, wherein the tab abutments a'e arranged for substantially parallel contact with the electrical contact tabs to be connected. The connecting device may comprise several separate parts that may be assembled to form parallel abutments on both sides of the electrical contact tabs. The connecting device may comprise U-shaped and/or J-shaped parts.
The connecting device may be welded to the tabs allowing the electrical interconnection of the selected cells between battery units within the module. The connecting device may be laser welded to the tabs. Thus, the interface between the connecting device and the tab may be welded to ensure optimum electrical contact therebetween.
The connecting device may be monometallic. The metal from which the connecting device is formed may be selected according to the metal from which the tabs are formed, The connecting device may comprise alumirium or copper.
The electrical contact tabs may be mechanically urged into contact with the connecting device, The electrical contact tabs may be pinched or pressed into engagement with the connecting device vvithin the elongate slots.
The electrical contact tabs within the elongate slots may be fused together to enhance electrical connectivity therebetvveen.
The electrical contact tabs may be joined to the connecting device by welding. The electrical contact tabs may be fusion vvelded to the connecting device, The electrical contact tabs may be laser welded to the connecting device, Pressing or pinching the loops of the connecting device into contact with the tabs increases the area of contact between the connecting device and the tabs. This facilitates contact between the tabs and the connecting device to ensure that a laser beam directed at the weld site provides consistent thermal mass to prevent overheating and vveld spatter, thus enabling a good electrical connection between the tabs and the connecting device. The pressing or pinching operation can be achieved using external tooling.
Thus, the invention facilitates the welding process thereby enabling formation of a secure electrical connection between the connecting device and the tabs, The connecting device may comprise a busbar.
The battery units making up the module may be any type of battery unit, such as those described with reference to the first, or ninth aspects of the invention, Any feature of the eighteenth aspect of the invention is equally applicable to the seventeenth aspect of the invention.
According to a nineteenth aspect of the invention there is provided a connecting device for connecting tabs of a battery wherein the connecting device comprises a monometallic strip having a corrugated form comprising a plurality of parallel loops provided with elongate tab receiving slots and wherein alternate loops are arranged for accepting tabs from a cell in use.
Thus, a generic connecting device or busbar may be provided and different arrangements of battery units within the module may be easily accommodated by cutting segments from the busbar to a required length to support the required configuration of terminal interconnections. Therefore, it is possible to have any configuration of battery units (units arranged in series, units arranged in pairs, units arranged in groups) with the connecting device or busbar cut to the requisite lengths.
Any of the first to nineteenth aspects of the invention may be combined with any other aspect, feature or embodiment detailed herein, in various mixed configurations and arrangements where appropriate.
Following is a description, by way of example only, of several embodiments for putting the invention into effect, with reference to the accompanying figures in which: Figure 1 is an exploded perspective view of a battery unit according to the invention comprising a cell with cell tabs extending from opposing sides of the cell; Figure 2 is a perspective view of a cassette frame of the battery unit of Figure 1; Figure 3 is an isometric view of an alternative embodiment of a cassete frame for use with the battery unit of Figure 1; Figure 4 is an exploded perspective view of a battery module including a plurality of battery units of Figure 1; Figure 5 is a perspective view of the assembled battery module of Figure 4 with battery units arranged in series; Figure 6 is a perspective view of an alternative embodiment of an assembled battery module with pairs of cells arranged in series; Figure 7 is a perspective view of an alternative embodiment of an assembled battery module with groups of three cells arranged in series; Figure 8 is an exploded perspective view of a battery unit with an alternative cooling system; Figures 9a, 9b and 9c are perspective and sectional views of a connecting member or busbar; Figure 10 is an exploded perspective of an alternative embodiment of a battery unit according to the invention with cell tabs extending from an upper end of the cell; Figure 11 is a front view of a pouch cell from the battery unit of Figure 10 with two tabs extending from an upper end of the cell; Figure 12 is a perspective view of a cassette frame from the battery unit of Figure 10; Figure 13 is a partial exploded perspealve view of the battery unit of Figure 10 showing tab retainers; Figure 14 is a perspective view of an alternative embodiment of a cassette frame showing moulded sensors and data processing means; Figure 15 is an exploded perspective view of a battery unit with an alternative cooling system; Figure 16 is an exploded perspective view of a battery module including a plurality of the battery units of Figure 10; Figure 17 is a perspective view of the assembled battery module of Figure 16 with battery units arranged in series; Figure 18 is a perspective view of an alternative embodiment of an assembled battery module with pairs of cells arranged in series; Figure 19 is a perspective view of an alternative embodiment of an assembled battery module with groups of three cells arranged in series; and Figures 20 to 28 are alternative embodiments of connecting devices.
A battery unit according to a first embodiment of the invention is shown generally at 10 in figure 1. The battery unit 10 includes a cell in the form of a pouch cell 11, an enclosure in the form of a cassette frame 20, two tab retainers 22,24, a heat transfer plate 38, and a compression member in the form of a foam pad 35.
The pouch cell 11 comprises an outer sealed polymer bag or pouch which contains a stack of positive electrodes (cathodes) and negative electrodes (anodes). A separator in the form of a thin microporous polymer layer electrically isolates the anodes from the cathodes. An electrolyte within the separator and surrounding the electrodes provides a liquid transport medium allowing transport of ions between the anodes and the cathodes. The electrolyte includes lithium ions as charge carriers. One example of a suitable pouch cell is described in W02019/034852A1, the entire contents of which are incorporated herein by reference.
Two cell tabs 12, 14 are internally connected to the stack of cathodes and anodes within the pouch cell 11. The distal end of the cell tabs 12, 14 extend outwardly on opposing sides of the cell 11. The lithium-ion cell electrochemistry dictates that an internal portion of the positive tab connecting to the cathode 12 is aluminium, and an internal portion of the negative tab 14 connecting to the anode is copper. One cell tab 14 comprises a 0.1 -0.5 mm thick bimetallic copper/aluminium strip and one cell tab 12 comprises a monometallic aluminium strip. The bimetallic strip is formed by placing a length of aluminium alongside a length of copper and:old rolling at high pressure to form a diffusion bond at the interface between the two metals. The bimetallic strip may then be annealed. The copper portion of the bimetallic strip is electroplated with tin or nickel to prevent corrosion. The bimetallic strip is cut into lengths of the required size to form the tab 14. The monometallic tab 12, comprising aluminium internally contacts the cathodes and the bimetallic tab 14 is oriented relative to the pouch cell 11 so that the copper end of the bimetallic strip contacts the anodes.
The positive tab 12 that is internally connected to the cathode of the pouch cell 11 extends outwardly from a side edge of the pouch cell 11. The negative tab 14 that is internally connected to the anode of the pouch cell 11 extends outwardly from an opposing side edge of the pouch cell 11. These tabs 12, 14 protruding from the pouch cell 11 enable external electrical connection of the cell. Both external portions of the tabs 12, 14 comprise aluminium. A unique receiving aperture 13, 15 is punched in each tab 12, 14 respectively. These apertures 13, 15 are unique in shape and in different positions offset with respect to the centre He of each tab 12, 14. The positive tab 12 has an elongate slot 13 at a predetermined location relative to the centreline of the pouch and the negative tab 14 has a circular slot 15 at an alternative location relative to the centreline of the cell 11.
According to an alternative embodiment of cell tab arrangement in a lithium-bn cell, the negative tab connecting to the anodes 14 is monometallic and made from copper. The positive tab 12 comprises the bimetallic strip and an internal portion of the positive tab 12 connecting to the cathodes is aluminium. Therefore, both outwardly extending ends of the tabs 12, 14 comprise copper according to this alternative embodiment, The enclosure in the form of a cassette frame 20 is shown in more detail in Figure 2. The cassette frame 20 is made from a plastic such as polycarbonate acrylonitrile butadiene styrene (PC-ABS) and is rectilinear in shape with a central rectangular hole 19. The cassette frame 20 incorporates profiled features that are produced by injection moulding the thermoplastic frame 20, The dimensions of the frame 20 are selected such that the body of the cell 11 is received between the profiled mouldings around edges of the frame 20 and the edges of the cell 11 are supported. Dimensions of the frame 20 are calculated to ensure that the tabs 12, 14 protrude by a predetermined amount beyond the edges of the frame 20 to enable external electrical connection of the battery unit 10.
Moulded profiled features of the cassette frame 20 include four tapered dowels 26 on a leading face of the cassette frame 20 and equispaced from each corner or the centreline. A reverse side of the cassette frame 20 includes four corresponding tapered recesses (not shown) equidistant from each corner of the frame 20. Each tapered recess is shaped to receive a dowel 26.1n use, these tapered dowels 26 and corresponding recesses enable alignment and stacking of multiple frames 20 in two different orientations within a battery module.
According to alternative embodiments, the tapered dowels 26 are substituted for different shapes and forms of interengaging features. Further embodiments include dowels 26 and corresponding recesses or other interengaging features located elsewhere on the cassette frame 20, while retaining the key functionality and the ability to position the frame 20 relative to an adjacent frame 20 in one of two positions by rotating the frame:hrough 180 degrees.
A moulded substantially cuboid recess 21 is formed in the frame 20 adjacent to each protruding dowel 26. The recesses 21 are shaped to accommodate electronic components such as a data storage means in the form of a semiconductor device (not shown) including a data processor and a wireless transmitter. Moulded channels 30 extend from each recess 21 parallel to a long edge of the frame 20 with perpendicular channels extending inwardly therefrom in the direction of the cell. The moulded channels 30 accommodate wires (not shown) to connect sensing elements with the semiconductor device. To improve clarity, the cassette frame 20 in Figures 1 and 2, is shown without the inclusion of electrical connectors, semiconductor device or cell monitoring means.
Sensors, semiconductor devices and means for electrical connection are well known and widely available, The semiconductor device located in the recess 21 in proximity to the cell 11 monitors, processes and stores voltage, current and temperature data received from sensors (not shown) located proximate to the cell 11 in use.
Side ends of the cassette frame 20 are provided with a tab retainer engaging feature 18. The tab retainer engaging features 18 are arranged to accept and retain inter-engaging portions of a respective tab retainer 22, 24, The tab retainers 22,24 have elongate slots that fit over the tabs 12, 14 once the pouch cell 11 has been assembled within the cassette frame 20. The tab retainers 22, 24 clip into the retainer engaging features 18 located on the side edges of the cassette frame 20. Each engaging feature 18 is unique to ensure that only the correct tab retainer 22,24 will retain and engage the correct tab 12, 14 according to predetermined polarity, The tab retainers 22,24 are designed such that they will only fit into their correct respective positions. This arrangement ensures correct positional location and polarity of the cell tabs 12, 14 for subsequent interconnection with a connecting device 50. The tab retainer 22 fitted over the positive tab 12 is coloured red and the tab retainer 14 fitted over the negative tab 14 is black in colour. These contrasting colours of tab retainers 22,24 provide easy visual identification of cell polarity, which facilitates subsequent interconnection of individual battery units within a module.
Locator keys are provided in the form of tab slots 13, 15 and corresponding moulded locating features 23, 25. Towards each side edge the leading face of the frame 20 includes a moulded locating feature 23,25 corresponding to the shape and relative location of the tab slots 13, 15 respectively. The cell 11 locates within the cassette frame 20 when the tab holes 13, 15 are aligned with the correct corresponding moulded locating feature 23, 25. If the cell 11 is incorrectly placed with respect to the frame 20, the locating features 23,25 and tab holes 15, 13 will be the wrong way around or misaligned with the result that the cell 11 vvill not fit in the cassette frame 20. Thus, the locating features dictate the correct alignment of the pouch cell 11 within the cassette frame 20 to ensure the cell 11 is correctly orientated and positioned with respect to a predetermined cell polarity. The locating keys provide both visual and physical identification of cell polarity.
When the battery unit is assembled, the pouch cell 11 is placed within the cassette frame 20 such that one planar face of the pouch cell 11 is in contact with the heat transfer plate 38. The cassette frame 20 containing the pouch cell 11 is assembled onto the heat transfer plate 38. The heat transfer plate 38 serves as a means of conducting heat away from the pouch cell 11 to an external heat sink, The heat transfer plate 38 is a thin rectilinear aluminium plate of around lmm thickness with the two leading long edges folded to create flanges 39. The flanges 39 provide the means by which the assembled battery unit 10 interfaces with an external heatsink when the battery unit 10 is assembled as part of a module in use. Aluminium is the preferred material according to the present embodiment since it combines low density with high thermal conductivity. The cassette frame 20 is accommodated between the flanges 39 such that the face of the pouch cell 11 is in contact vvith the aluminium plate 38 through the hole 19 of the cassette frame 20.
The heat transfer plate 38 also acts as a backing plate for the battery unit 10. The heat transfer plate 38 is electrically isolated from the pouch cell 11 by a suitable thin film insulator or insulating coating disposed on the heat transfer plate 38 or pouch cell 11 in such a way that thermal conductivity of the thermal transfer plate 38 is not compromised.
According to the present embodiment a DuPont Kapton MT film (not shown) is interposed between the thermal transfer plate 38 and the face of the pouch cell 11. Alternatively, a polysiloxane coating could be used for isolation. This film or coating provides good electrical insulation with high thermal conductivity. When the battery unit 10 is assembled, one substantially planar face of the pouch cell 11 is in indirect contact with the heat transfer plate 38 vvith the thin isolation film interposed for electrical isolation therebetween. The heat transfer plate 38 efficiently permits cooling of the cell 11 during charge and discharge.
A resilient compression member in the form of a thin foam pad 35 arranged to cover a leading face of the pouch cell 11 and provide a compression pressure thereto.
Maintenance of a knovvn and controlled compressive force on the pouch cell 11 in use is advantageous, otherwise, the cell 11 can suffer from energy capacity loss over time due to internal electrode separation. The foam pad 35 is compressible to provide a uniform compressive pressure over the planar surface of the pouch cell 11 when the battery unit 10 Is assembled. Dimensions of the cassette frame 20 are selected to partially accommodate the foam pad 35 and the thickness of the foam pad 35 is selected so that it will extend above the upper surface of the cassette frame 20. The foam pad 35 has known compression force deflection characteristics and low compression set. Along with a known thickness, these characteristics enable calculation of the compressive force applied to the pouch cell 11 when the battery unit 10 is in an assembled configuration.
An alternative embodiment of a cassette frame 220 for the pouch cell 11 is shown in Figure 3. Like components have the same two-digit reference number with a third digit '2' placed before the two digits. These components are similar or identical to those previously described unless otherwise stated. The cassette frame 220 also includes embedded functionality incorporating features that accent electronic components and circuitry for the purpose of monitoring the pouch cell 11 contained within the cassette frame 220. The cassette frame 220 provides electrical connection to sensing elements 232 by means of leadframe metal conductors 231, such as nickel-or tin-plated copper that are.ntegrated within the moulded cassette frame 220 using a process known as leadframe overmoulding. The leadframe metal conductors 231 provide robust interconnection of electrical components since the electrical conductors are embedded within the plastic moulded frame 220 and only exposed where interconnections to external components are required. Examples of suitable interconnection processes are ultrasonic wire bonding or thermosonic bonding. The wire bonds are subsequently encapsulated in a suitable material, for example UV curable resin to provide mechanical and environmental protection. The leadframe metal conductors 231 electrically connect the sensing elements with a data storage, processing and transmission means such as a semiconductor device (not shown) that is located in the moulded recess 221. This arrangement facilitates electrical connection from the semiconductor device to the cell tabs 12, 14 for voltage and current sensing and to temperature sensing elements 232 at spaced locations along the face of the pouch cell 11, Further leadframe metal conductors 231 can provide an external wired connection 233 from the battery unit 13. The wired connection 233 may be used to enable a direct wired communication with the semiconductor device and a battery management system (not shown) during normal use, or thereafter for the retr eval of stored data connected with the cell 11.
Again, the frame 220 comprises locator keys in the form of moulded features 223, 225 arranged to engage with the receiving slots 13, 15 punched into the cell tabs 12, 14. These locating features with corresponding shapes ensure the pouch cell 11 is correctly aligned and oriented within the cassette frame 220.
Thus, the battery unit 10 provides a self-contained energy storage and discharge means incorporating a cell performance monitoring system electrically connected to a semiconductor device to record cell 11 data, wherein all components are integrated within the cassette frame 20, 220.
A plurality of assembled battery units 10 are incorporated into a battery module 40 as shown in Figures 4 and 5. The battery module 40 enables the cells 11 to be physically and electrically interconnected by joining the cell tabs 12, 14 to external connectors in the form of busbars 50. The requisite number of battery units 10 comprising pouch cells 11, cassette frames 20, 220, foam pads 35 and heat transfer plates 38 are stacked between two rigid end plates 41 to form a battery module 40, Stacking and proper alignment is facilitated by the tapered dowels 26, 226 extending from a leading end of each frame 20, 220 and locating in the corresponding recesses on the rear side of each adjacent cassette frame 20, 220 thereby providing the means for positive and accurate location of each cassette frame 20, 220 within the stack.
Structural end plates 41 are provided to ensure rigid structural support for the battery module. The end plates 41 have indentations (castellations in cross-section) such that the plates 41 comprise material on two substantially parallel planar surfaces linked by material disposed substantially perpendicular to the two spaced parallel planar faces. Thus, the end plates 41 exhibit a neutral axis between the two parallel planar surfaces. As a result of this design, the end plate 41 has high strength while minimising the amount of material required. Furthermore, the end plate 41 design enables manufacture by die casting of a lightweight aluminium alloy, thereby minimising manufacturing costs. Hence the end plates 41 are designed with sufficient strength while saving material costs, manufacturing costs and weight. Since the end plates 41 are constructed from aluminium a thermal barrier 44 of epoxy glass laminate is interposed between each end plate 41 and the outer battery unit 10. The thermal barrier 44 is provided to negate the cooling effect on the outer pouch cells11 to maintain temperature uniformity across all cells 11 within the battery module 40. The barrier 44 also spreads the load from the end plate 41 onto the planar face of the pouch cell 11 otherwise the castellated end plate 41 would produce localised high and low pressure areas on the surface of the end cell 11. The end plates 41 incorporate features that facilitate installation of the module 40 within a battery pack (not shown).
The end plates 41 described above are the preferred embodiment. However, alternative embodiments may incorporate end plates with different profiles and designs while maintaining the required functionality (strength and rigidity). Such embodiments could be high pressure or low pressure die cast, sand cast, machined or the like. Alternatives to the described end plates 41 include wood or plastic end plates (the latter moulded or vacuum formed) constructed from a sufficiently robust and warpage free material. According to another embodiment, structural end plates could be produced using a lightweight carbon fibre composite material (with a filler) which removes the requirement for a thermal barrier between the end plates and the outermost battery unit 10. However, the manufacture of such embodiments is more complex and proolematic, thereby increasing costs.
When the battery units 10 comprising the heat transfer plate 38, 538, the cassette frame 20, 220, the pouch cell 11 and the foam pad 35, are stacked in the required configuration, a force is applied so that the faces of the frames 20, 220 are brought into contact. As a result, the foam pads 35 within each battery unit 10 are compressed to apply a uniform force to the surface of each cell 11 within the stack. External mechanical retemion and maintenance of a compressive force to the stack is achieved by means of threaded studs 45 secured along the length of the module into the end plates 41. The threaded studs 45 act to ensure the battery module 40 is mechanically secure and achieve the correct cell 11 compression force.
According to an alternative embodiment, the end plates 41 and internal battery units 10 are mechanically secured by means of metal straps (not shovvn) surrounding the battery module 40.The straps are tensioned to give tne required amount of compressive force.
Energy, voltage, current and in turn power requirements for different applications can be accommodated by selecting the number and interconnection of the battery units 10 accordingly. For example, if the cells 11 are required to be electrically connected in a series configuration, then each alternate battery unit 10 is stacked and orientated at 180 degrees with respect to the previous battery unit 10 such that the positive tabs 12 are positioned adjacent to the negative tabs 14 of the adjacent cells 11. This series configuration of a battery module 40 is shown in Figures 4 and 5.
Figure 6 shows a battery module 340 made up from the series connection of cell 11 pairs, wherein the first two battery units 10 are stac<ed in the same orientation and the next two battery units 10 are orientated at 180 degrees. The cell pairs are electrically connected within the module 340 by busbars 350 cut to the required length. The total number of pairs of battery units 10 in the stack is selected according to the module 340 voltage required.
Figure 7 shows a battery module 440 made up from series connection of groups of three adjacent cells 11, wherein the first three battery units 10 are stacked in the same orientation and the next three battery units 10 are orientated at 180 degrees, Again, the groups of three cells are electrically connected within the module 440 by busbars 450 cut to the required length. According to other embodiments, various different configurations of battery units 10 within the battery modules are accommodated by stacking the battery units 10 in the appropriate corresponding arrangements.
According to the present embodiment, the connector or busbar 50, 350,450 has a corrugated profile shown in Figures 9a to 9c with rounded loops having peaks 51 and troughs 52. The peaks 51 are provided with elongate tab receiving slots 53 punched therethrough to enable visual confirmation that the tabs are seated and connected to the busbar 50, 350,450 following assembly of each battery module 40, 340, 440. The busbar 50, 350,450 is monometallic and comprises aluminium. The busbar 50, 350, 450 is manufactured using a simple press and is produced as strips of thickness typically in the range of 0.5 -1.0mm and of the same width as the cell tabs 12, 14. The aluminium busbar 50,350,450 may be annealed to improve ductility. The corrugated profile of the busbar 50, 350,450 is intended to accommodate cell tabs 12, 14 within each alternate rounded peak 51 as shown in Figure 9c.
According to an alternative embodiment, connecting devices in the form of monometallic busbars may be made from copper to match the material of cell tabs, where these are also made from copper, The copper busbar may be electroplated with tin or nickel. Tin is preferred for laser welding because energy loss is reduced through surface reflection. Tin also has a low melting point and readily alloys with copper. Overall, aluminium is the preferred busbar 50, 350,450 material for the present embodiment due to its low melting point that facilitates the laser weld connection with the cell tabs 12, 14. Additionally, aluminium is lighter and lower cost compared with copper, although it has slightly lower electrical and thermal conductivities.
The elongate slots 53 formed in the rounded peaks 51 provide physical location or visual confirmation that the cell tab 12,14 is positioned correctly vvith the top of the tab 12,14 in contact with the corresponding part of the busbar 50, 350,450 without any undesirable gap. Subsequent laser welding requires components to be joined or in contact. Air gaps can cause temperature rises that lead to excessive melting and poor bonding. External tools are used to pinch either side of the rounded peak 51 in a pincer movement around each tab 12, 14 so as to positively engage the busbar 50, 350,450 with the tabs 12, 14.
Each adjacent intermediate peak 51 which does not contain a cell tab 12, 14 serves to nullify the squeezing process by providing means of allowing the busbar 50, 350, 450 to deform and extend lengthvvise thereby ensuring the tabs 12, 14 remain in a vertical position. Application of a downward force on each adjacent loop may be required to achieve the necessary deformation.
The different applications require alternative configurations of battery units 10 to be connected in series (Figure 5), in pairs (Figure 6), in groups of three (Figure 7) each require busbars 50, 350, 450 of different lengths. This is achieved by cutting the busbars 50, 350, 450 to the appropriate length according to the battery module 40, 340,440 requirements.
Alternatively, busbars may be initially formed to the required length. For example, if cells 11 are to be connected in series as in Figure 5, the busbar 50 connects the positive tab 12 of the first cell 11 within the first battery unit 10 with the negative tab 14 of the adjacent cell 11 in the next battery unit 10. This pattern is repeated at the opposing end of each cell 11 and unit 10 where the positive tab 12 of the second cell 11 is connected to the negative tab 14 of the third cell 11.
Where battery units 10 are connected in cell pairs as in Figure 6 a longer busbar 350 is necessary to connect the positive tabs 12 of the first pair of cells 11 to the negative tabs 14 of the second pair of cells 11, Corresponding y, at the opposite end of the battery units 10, the busbar 350 connects the positive tabs 12 of the second pair with the negative tabs 14 of the third pair of cells 11. By cutting a suitable length of busbar 50, 350,450 further interconnection arrangements are facilitated. At either end of the battery module 40, 340, 440 a modified busbar is provided which incorporates a terminal to allow external electrical connection of the battery module 40, 340, 440.
The busbar 50, 350,450 is advantageous since it is a generic device for connecting tabs of the same metallurgy and using varied arrangements of cells 11.The invention does not require a bespoke connecting device for different arrangements of modules 40, 340,440. Rather, the busbar 50, 350,450 of the invention is sufficiently versatile that the same connector can be used for all applications by cutting sections of busbar 50, 350, 450 to the required length.
Connection is made between the busbar 50, 350, 450 and the enclosed cell tabs 12, 14 by laser welding. The pinching process for ensuring dose fit between the cell tabs 12, 14 and the busbar 50, 350, 450 is intended to ensure that the thermal mass is consistent during the welding process, The welding process is performed on busbars 50, 350,450 on both sides of the module 40, 340, 440. The laser is directed so that the beam is incident on areas of the busbar 50, 350,450 in physical contact with the underlying cell tab 12,14, thereby causing the materials to melt and weld together. When the welding process is complete plastic covers 56 are attached over the busbars 50, 350,450 on either side of the modules 40,340, 440 to provide mechanical protection and electrical isolation.
The module 40, 340,440 is mounted on to an external cooling plate 57 so that the flanges 39 of the heat transfer plates 38 of the individual battery units 10 are in contact with an inner surface of the module cooling plate 57. A thermally conductive grease, paste or other conductive medium, such as a thermally conductive pad, aids thermal transfer at the interface between the flanges 39 and the plate 57. The cooling plate 57 consists of two aluminium plates having passages formed by photoetching or machining on:he internal faces (not shown). The internal faces of the aluminium plates are joined by brazing such that the passages are enclosed between the plates to create fluid channels. The channels are designed to provide a continuous path through the cooling plate 57, within which a liquid coolant can flow. Ports 59 are provided at suitable point to permit entry and exit of the fluid coolant within the plate 57.
Another alternative embodiment of a battery unit 510 is shown in Figure 8. The battery unit 510 has a different cooling arrangement for the pouch cell 11. A thin liquid cooled plate 538 is constructed as the described above. The rest of the battery unit 510 is similar to the battery unit 10 previously described, however the liquid cooled plate 528 of the battery unit 510 may result in more effective thermal transfer and therefore be more suitable for applications where the charging or environmental conditions are likely to result in increased heating of cells 11 within the battery unit 510.
A battery pack (not shown) can be formed using the required number of the battery modules 40,340, 440 to generate the specified voltage for a particular application. The battery pack can also be provided with multiple additional sensors and a data management system (not shown) for monito'ing and controlling the cells. Battery packs may be used to supply and/or store power in vehicles for auxiliary or mobile applications or structural facilities for stationary applications.
Figures 10 to 19 cover alternative embodiments of battery units 110,810 and resulting modules 140, 640, 740. Each battery unit 110,810 comprises pouch cells 111 having positive and negative tabs 112, 114 extending from the same side of the cell. The pouch cell 111 has a positive and a negative tab 112, 114, Each tab 112, 114 has a different width. One tab is monometallic and the other tab is formed from the bi-metal copper/aluminium strip previously described.The positive tab 112 has a width of 40mm and the negative tab 112 has a width of 45mm.The tabs 112, 114 are symmetrical with regard to the centre line of the cell 111, such that the centre line of the narrower positive tab 112 and that of the wider negative tab 114 are equidistant from the centreline of the cell 111, Although the location of certain components of the battery unit 110 differ from some components described with reference to the battery unit 10 according to the previously described embodiments of the invention, the chemistry and function of the components is comparable. Like components have been labelled with the same two-digit reference number with a third number '1', '6', '7' or'8' placed before the two digits. Such components function in a similar way as those previously described unless otherwise expressed.
There are many advantages of the described embodiments that represent advances over conventional battery cells, units and modules.
The invention includes generic components wherein the same feature is usable in different designs of battery unit 10, 110,810 thereby easily permitting alternative configurations. For example, the interconnection between the cell tabs 12, 14 and a busbar 50 arrangement is facilitated since both positive and negative cell tabs 12, 14 comprise the same material, (tin or nickel plated copper or aluminium) and the busbar 50 is produced in the same material as the cell tabs 12, 14. The assembly of various different arrangements of battery units 10, 110 into a module 40, 340, 440, 140, 640, 740 is facilitated by the use of a generic busbar 50, 350, 450, 650, 750 that is cut to the required length to support the specified arrangement of cells 11.
Physical and visual identifiers also support the generic model of battery as the contrasting colours of the cell retainers 22, 24, 122, 124 provide immediate visual identification of the particular battery module 40, 340, 440, 140, 640, 740 configurations. Measures such as the locator keys13, 15, 113, 115, 23, 25 provided on both the tabs 12, 14, 112, 114 and moulded into the frame 20, 220, 120,820 constrain the assembly of the pouch cell 11, 111 within the cassette frame 20, 220, 120,820 to the correct orientation and position to reduce the likelihood of assembly error. The battery unit is versatile and can be rotated by degrees so that the cell and tabs can be used in either configuration presenting cell tabs in two different positions. Different numbers of battery units can be interconnected in the desired formation to produce various options for grouping of cells depending on the application requirements. It is particularly advantageous that the invention enables a multiplicity of cells 11, 111 to be packaged and electrically connected in a variety of configurations and this is of assistance in building a standard format for multiple applications and requirements. A generic module enables the more convenient use of alternative configurations for different markets by adapting the means of interconnection of the cells 11 to the particular application.
All the described embodiments represent an advance on conventional battery units and modules. The packaging format of pouch cells 11, 111 offers higher volumetric and gravimetric energy densities compared with hard cased cell formats. The pouch cells 11, 111 are cooled by means of the heat transfer plates 38, 538, 138,838 which is facilitated by the large planar surface area of the pouch cells 11, 111, as well as using module cooling plates 57,157 to further restrict the possibility of the pouch cells 11,111 overheating in use. Efficient cooling is a significant consideration to prolong cell 11, 111 lifetime due to greater market demands for shorter charging times and higher performance.
The multiple temperature sensors 232 spaced along the face of the pouch cell 11 facilitates simultaneous temperature measurement at different points on the cell and data from the various sensors can provide early indications of abnormal behaviour or malfunction thereby allowing the battery management system to implement appropriate action. Sensing elements, a semiconductor device and electrical connections are all embedded within the battery unit 10, 110 to provide a self-contained unit incorporating data relating to cell performance.
A potential disadvantage of pouch cells 11, 111 is their vulnerability to mechanical damage. This is minimised by the provision of the moulded plastic frame 20, 220, 120,820 extending around the perimeter of each cell 11, 111 to provide mechanical protection. The described embodiments enable the pouch cells 11 within the battery units 10, 110 and modules 40, 140 to be maintained under compression to maximise their service life. The compression prevents separation of the electrode layers which would cause loss of energy capacity over time.
Second life applications are facilitated by retaining each cell 11 within its cassette frame 20, 220 with associated sensing elements 32, which are handled as an integrated unit during disassembly and re-use. The embedded semiconductor device provides information on the health of individual cells 11, 111, which is crucial to the assembly of effective battery modules by enabling effective matching of cells 11 for second life applications. The embedded data provided for each individual battery unit 10 gives flexibility in the way in which cells 11 may be reused. Conventional battery arrangements give no information on the status and/or health of individual cells 11 for second life applications,Thus re-use of conventional cells is inhibited as inclusion of an unfit cell 11 or a cell 11 with mismatched capacity could adversely affect the performance of an entire battery module 40.
Alternative embodiments of connecting devices in the form of busbars are shown in Figures 20 to 28. The busbars are monometal ic and formed from a metal chosen to match the metallurgy of the outwardly extending cell tabs which they are intended to receive.
Figures 20 and 21 show an alternative busbar 70 comprising a planar body 72 with equispaced parallel U-shaped ridges 71 provided with elongate slots shaped and arranged to receive cell tabs. Pinching of the ridges 71 of the busbar 70 using an external tool results in contact between the tabs and the busbar70, which is necessary prior to laser welding to join the tab and busbar 70 for electrical connection therebetween. The act of pinching the ridges 71 causes a reduction in the overall length of the busbar 70 resulting in a deflection of the tabs. Such defection may be advantageous for electrical isolation.
An alternative busbar 75 with similar features is also shown in Figure 21, with the difference that the body 76 of the busbar is U-shaped, such that the busbar 75 has a nonuniform corrugated profile Figure 23 shows a basic form of busbar 80. The busbar 80 comprises a monometallic sheet 82 provided vvith elongate tab receiving slots. An alternative similar busbar 85 shown in Figure 24 also comprises a monometallic sheet 86, with the addition of locating holes 87 to enable accurate positioning and visual location of the tabs and to facilitate welding.
According to some embodiments, welding may take place through the locating holes 87, which also provide visual evidence that the busbar 85 is fully engaged with the tabs.
In a simpler embodiment (not shown), a busbar is cut from a sheet of metal without any metalwork or forming required. The sheet busbar is cut to the required size but no holes or slots are provided. Instead, tabs are folded and laid flat against the underside of the busbar, which is welded to the tabs. This embodiment is simple, inexpensive and provides good contact between the tabs and busbar.
Three more alternative busbars 90, 94,95 are shown in Figures 25 and 26. Each busbar 90, 94,95 is provided in discrete parts and assembled around the tabs to provide parallel abutment members 91,98 that form a parallel contact along each side of the tabs. Each of the busbars 90, 94, 95 have a substantially planar body portion 92,97 formed from sheet metal. Separate U-shaped portions 9399 with abutment members 91,98 extend substantially perpendicular to the planar body portion 92, 97, Advantageously, the shape and arrangement of the abutment members 91,98 on either side of each tab facilitate pressing of the tab into contact with the abutment member 91, 98. Thus, any air gaps between the tabs and the abutment members 91, 98 are minimised. The resultant welded connection for the electrical interface between each tab and the busbar 90, 94,95 is thereby improved and tvvo joins are created on either side of the tab during the vvelding process to establish a successful welded connection.
The busbar 9415 shown in Figures 27 and 28. A base 99 of each U-shaped abu:ment portion 98 is arranged to lie close to the plane of the planar body portion 97. A retaining bar 100 is a further part of the busbar 94 and serves to support the base 99 of the U-shaped abutment portion 98. The individual parts may be spot welded to hold them in place as a sub-assembly around the tabs. Once the busbar 94 is assembled around the tabs, the abutment portions 98 are fusion welded from above to form the join with the tabs. This vertical weld is advantageous for several reasons: there are two potential welds on each side of the tab; the join can be enhanced on either side of the tab to ensure good electrical interconnection; and, the weld does not burn through a layer of material. Figure 28 shows the abutment members 98 once they have been fusion welded to the tabs and the material of the tabs and the busbar 94 are joined to form an electrical connection.
The busbar 95 has identical component parts to the described busbar 94. However, the busbar 95 is assembled in inverse relation to the busbar 94.1n use, within a battery module where combinations of battery units are interconnected in different vvays according to the required output, the busbars 94,95 may be used alternately along the edge of the battery module. This alternate arrangement of busbars 94,95 is advantageous since the planar body portions 97 of adjacent busbars 94,95 lie on different parallel planes (as shown in Figure 26). Thus, the free edges of each busbar 94,95 are also vertically (as well as horizontally) spaced. As a result, there is greater clearance between edges of adjacent busbars 94, 95. The improved clearance between adjacent busbars 94,95 minThises the risk of current conducting across the gaps, which can be a greater concern for high potential battery modules. Thus, advantageously, two different types of busbars 94,95 may be formed from a single manufacturing pattern and can be assembled in inverse orientation from the same parts.
The busbar 90 has some similarities with the busbar 94. However, the L1 shaped portion 93 of the busbar 90 is loosely held (rather than spot welded) in position by two foldable flaps which are folded down after the busbar 90 sub assembly is constructed and prior to assembly onto the cell tabs. For the length of busbars 90, 94,95 shown in Figure 26, the busbar 90 is constructed from three parts and the busbars 94,95 are constructed from five parts. Thus, the busbar 90 has fewer component parts and offers more flexibility of assembly. The busbar 90 has leading and distal edges 96 that are angled in opposing directions. Again, the purpose of the angled edges 96 is to separate adjacent busbars 95 to prevent current jump across the gaps in high potential applications. As shown in Figure 26 adjacent busbars 90 are arranged such that the upturned edge 96 of one busbar 90 is positioned alongside the dovvnturned edge 96 of the next busbar 90.
Any of the busbars 70, 75, 80, 85, 90, 94,95 described in the alternative embodiments with reference to figures 20 to 28 can be manufactured to the required size, or cut:o the required length where appropriate, to match the requirements of each specific application with regard to the number of tab connections. Appropriate lengths of the busbars 70, 75, 80, 85, 90,94,95 may be used in place of the busbars 50, 350, 450, 150, 650, 750 described with reference to earlier embodiments. Different configurations and arrangements of battery units 10, 110 will be required according to specific applications requiring specified voltage and capacity. Each of these different interconnection solutions can be met by any of the busbars 50,70, 75, 80, 85, 90, 94, 95 manufactured or cut to the appropriate length.
Modifications and improvements can be made without departing from the scope of the invention. Where used, dimensions (such as those for tab width) provide a detailed example only and such components are not limited to the specific exemplary values.
For example, the invention may be used with different or new cell formats where appropriate. The invention may be used with cells having different electrochemistry, such as cells using sodium ions instead of lithium ions. Embodiments of the invention incorporating sodium ion cells would use aluminium for both positive and negative tabs.
The electrical interconnections between sensing elements and semiconductor devices within each battery unit 10, 110 can be achieved by any suitable method such as embedded wires, printed circuit board, optical connections, leadframe overmoulding or moulding the enclosure around the components of the battery unit 10, 110 to form an integrally moulded unit.
Other embodiments may include enclosure or cassette frames 20, 120 having different, shapes, forms and mouldings and/or made from alternative materials, The heat transfer plates 38, 138 can be formed from any suitable conductive material. Alternative module cooling arrangements and/or materials for cooling plates 57, 157 may be used.
End plates 41 of the battery module 40 may be formed from any suitable lightweight material with the required stiffness and strength. Alternative embodiments may include composite materials such as carbon fibre. Where end plates 41 are formed from aluminium or any other material with significant thermal mass, a thermal barrier 4415 interposed between the outer battery unit 10 and the end plates 41. Various materials with sufficient stiffness, lovv thermal conductivity and low compressibility can be used for the thermal barrier 44, Any configuration or number of battery units 10 within a module can be provided depending on the voltage and application requirements.
Relative terms such as "edge", "leading", "opposing", "side" etc are used by way of explanation only and are not intended to be limiting.
Numbered Paragraphs 1. A battery unit comprising: a cell for the storage and discharge of electrochemical energy; a cell monitoring system associated with the cell and adapted to monitor at least one characteristic of the cell; a data storage means electrically connected to the cell monitoring system and adapted to store at least a portion of the data received from the cell monitoring system; 20 and an enclosure configured and arranged to accommodate the cell monitoring system, data storage means and at least partially support the cell.
2. A battery unit according to paragraph 1, wherein the cell monitoring system includes a plurality of sensor elements to monitor one or more of the following characteristics associated with the cell: voltage, current, resistance and/or temperature.
3. A battery unit according to paragraph 1 or paragraph 2, wherein the cell monitoring system comprises at least one temperature sensor located proximate or on the surface of the cell wherein the at least one temperature sensor is electrically connected to the data storage means.
4. A battery unit according to any of the preceding numbered paragraphs, wherein the cell monitoring system comprises a plurality of temperature sensors spaced at intervals along the surface of the cell, wherein each temperature sensor is electrically connected to the data storage means.
5. A battery unit according to any of the preceding numbered paragraphs, wherein the cell comprises a positive contact tab and a negative contact tab and wherein the cell monitoring system provides an electrical connection between the cell tabs and the data storage system for the measurement and recordal of voltage and/or internal resistance characteristics of the cell.
6. A battery unit according to any of the preceding numbered paragraphs, wherein the battery unit further comprises a contactless data transmitter electrically connected to the data storage means and arranged for the selective arid remote transmission of data from the data storage means to an external source.
7. A battery unit according to any of the preceding numbered paragraphs, wherein at least one of the cell monitoring system, electrical connectors and/or data management is at least partially embedded within the enclosure.
8. A battery unit according to any of the preceding numbered paragraphs, wherein the enclosure comprises at least one recessed aperture for accommodating the data storage means.
9. A battery unit according to any of the preceding numbered paragraphs, wherein the cell monitoring system and the data storage means are connected by electrical connectors embedded or integrated within the enclosure.
10. A battery unit according to any of the preceding numbered paragraphs wherein at least a portion of the data storage means and electrical connectors are encapsulated in a protective material selected to provide mechanical and environmental protection of the data storage means and/or electrical connectors.
11. A battery unit according to any of the preceding numbered paragraphs, wherein the battery unit further comprises a compression member arranged to act on the cell and exert a uniform compressive force thereon.
12. A battery unit according to paragraph 11, wherein the compression member has a substantially planar face that corresponds to a substantially planar face of the cell and wherein the compression member is accommodated alongside the cell within the enclosure, such that the planar face of the cell contacts the corresponding planar face of the compression member and wherein the compression member is accommodated within the assembled battery unit in a compressed configuration in which a known compressive force is exerted on the cell.
13. A battery unit according to paragraph 11 or paragraph 12, wherein the compression member comprises a resiliently deformable material and the dimensions of the enclosure are selected to accommodate the cell and the compression member only in a compressed configuration such that the cell is compressed by a known deflection in the assembled battery unit.
14. A battery unit according to any of the preceding numbered paragraphs, wherein the battery unit comprises a heat transfer member that is located alongside at least a portion of a planar face of the cell, wherein the heat transfer member is electrically isolated from the cell and arranged to transfer excess heat away from the cell 15. A battery unit according to paragraph 14, wherein the heat transfer member comprises a heat transfer plate made from a thermally conductive material, and wherein the heat transfer plate acts as a backing plate for the battery unit.
16. A battery unit according to paragraph 14 or paragraph 15, wherein the heat transfer member comprises a channel allowing the circulation of a coolant within the channel in use.
17. A battery unit according to any of the preceding numbered paragraphs, wherein the battery unit comprises locator keys associated with the enclosure and the cell, wherein the locator keys constrain orientation of the cell within the enclosure in the assembled battery unit thereby ensuring the cell is in the correct orientation and position with respect to predetermined polarity.
18. A battery unit according to paragraph 17, wherein the locator keys comprise different moulded features provided on the enclosure, each moulded feature having a corresponding receiving aperture located on a respective cell tab, such that the cell is constrained to the preselected orientation within the enclosure to enable assembly of the battery unit 19. A battery unit according to any of the preceding numbered paragraphs, wherein the battery unit comprises two tab retainers for retaining the tabs of the cell, wherein each tab retainer is cooperatively engageable with the enclosure in one position and wherein the tab retainers comprise a visual identification of polarity such that the preselected tab retainer is only engageable with the enclosure over the associated tab with specific polarity thereby providing a reliable visual identification of tab polarity.
20. A battery unit according to any preceding numbered paragraph, wherein the cell comprises a positive contact tab and a negative contact tab, the contact tabs enabling the interconnection of the battery unit to an external source and wherein one of the contact tabs comprises a bimetallic strip.
21. A battery unit according to paragraph 20, wherein the bimetallic strip has one end formed form a second metal for internal electrical contact within the cell tab and another end that extends outwardly from the cell formed from a first metal, and wherein the other contact tab is monometallic and formed from the first metal such that outwardly extending ends of both tabs are formed from the same metal.
22. A battery module comprising a plurality of interconnected battery units according to any one of numbered paragraphs 1 to 21.
23. A battery module according to paragraph 22, comprising connecting devices for electrically connecting selected tabs of adjacent battery units, wherein battery units are arranged such that the polarity of adjacent cell tabs is in a preselected orientation and connecting devices of a required length are electrically connected to the tabs in the desired orientation.
24. A battery module according to paragraph 23, vvherein each connecting element has elongate slots for receiving cell tabs and wherein tabs are pinched into contact with the connecting device within the tab receiving slot.
25. A battery module according to paragraph 23 or paragraph 24, wherein the connecting device is monometallic and formed from a same metal as the outwardly extending portion of each cell tab 26. A battery module according to any one of paragraphs 22 to 25, when dependent on any of paragraphs 14 to 16, wherein the battery module comprises a module cooling arrangement to substantially restrict overheating of the module in use, wherein the module cooling arrangement comprises at least one cooling plate that interfaces with thermal transfer member of each battery unit.
27. A battery module according to paragraph 26, wherein the module cooling arrangement comprises at least one plate having a channel allowing the circulation of a coolant within the channel in use and wherein the at least one cooling plate acts as a backing plate for the module.
28. A battery module according to any one of paragraphs 22 to 27, wherein the battery module comprises a compression mechanism for applying a compressive force to stacked battery units within the module.
29. A structure comprising one or more battery units according to any of paragraphs 1 to 21 for stationary applications.
30. A movable entity comprising one or more battery units according to any of paragraphs 1 to 21 for mobile applications.
31. An enclosure for a pouch cell, the enclosure comprising a rigid frame for at least partially supporting edges of a pouch cell, wherein the enclosure comprises embedded electrical connectors and a data storage means accommodated within a data storage compartment moulded into the frame, wherein the embedded electrical connectors are arranged to connect at least one monitoring device with the data storage means accommodated in the data storage compartment.
32. A pouch cell comprising: at least one anode, at least one cathode, with a separator and an electrolyte disposed between each anode and cathode, an outer pouch sealed around the anode(s), cathode(s), electrolyte and separator(s), tvvo tabs extending outvvardly from the pouch and in internal electrical contact with the anode and the cathode, wherein one tab comprises a bimetallic strip having first and second metals at respective ends of the bimetallic strip, and one monometallic tab formed from the first metal; and wherein the outwardly extending portion of each tab comprises the first metal and therefore the metals of each cell tab in contact with the internal anode(s) and the internal cathode(s) within the pouch are different, 33. A battery unit comprising: a cell for the storage and discharge of electrochemical energy, wherein the cell comprises a positive external contact tab and a negative external contact tab, both tabs arranged for external electrical connection; an enclosure for receiving and at least partially supporting edges of the cell; and a cell orientation system associated with at least one of the cell and/or the enclosure, wherein the cell orientation system is arranged to orient the cell wiThin the enclosure such that the cell contact tabs extend in a predetermined orientation relative to the enclosure.
34. A battery unit according to paragraph 33, wherein the cell orientation system is configured such that assembly of the components of the battery unit is only possible when the cell is oriented correctly within the enclosure with respect to the predetermined cell polarity.
35. A battery unit according to paragraph 33 or paragraph 34, wherein the cell orientation system comprises locator keys provided on at least one of the cell and/or the enclosure, wherein the locator keys constrain orientation of the cell to the predetermined location within the enclosure.
36. A battery unit according to paragraph 35 wherein the locator keys comprise at least one co-operable locating member and receiving aperture provided on the cell and the enclosure.
37. A battery unit according to any one of paragraphs 33 to 36, wherein the cell orientation system comprises two unique locator members moulded into the enclosure and wherein each locator member is cooperable with a complementary receiving aperture provided on tabs extending outwardly from the cell.
38. A battery unit according to any one of paragraphs 33 to 37, wherein each tab or locator key member extends from the cell in a location relative to a centre line of the cell, such that the corresponding locator keys only engage in the correct orientation of the cell otherwise the relative connection of the key features is mismatched.
39. A battery unit according to any one of paragraphs 33 to 38 wherein the cell orientation system comprises a visual polarity identifier to provide a visual reference for predetermined cell orientation within the enclosure.
40. A battery unit according to any one of paragraphs 33 to 39 wherein the battery unit further comprises a polarity identification system arranged to identify the polarity of each tab extending from the battery unit and wherein the polarity identification system is arranged and configured such that assembly of the components of the battery unit is only possible with the polarity identification system in the predetermined position.
41. A battery unit according to paragraph 40, wherein the polarity identification system comprises a visual identifier to identify the polarity of each tab of the battery unit.
42. A battery unit according to paragraph 40 or paragraph 41, wherein the battery unit further comprises tab retainers, each tab retainer having an elongate slot for receiving a tab and wherein the tab retainers are each provided with a unique inter-engaging feature such that each tab retainer may only engage with the enclosure around and over the predetermined tab.
43. A battery unit according to paragraph 42, wherein the tab retainers comprise contrasting colours for visual identification of tab polarity thereby incorporating dual functionality of retaining the tabs and signalling polarity.
44. A battery unit according to any one of paragraphs 33 to 43, the battery unit comprising an alignment feature spaced from each of the four corners of the battery unit to ensure that the battery unit is alignable in a predetermined configuration with respect to adjacent battery units when assembled into a module.
45. A battery unit according to paragraph 44, wherein the alignment features comprise tapered dowels on one leading face of the battery unit and complementary recesses on an opposing face of the battery unit.
46. A battery unit according to any one of paragraphs 33 to 45, further comprising a cell monitoring system including at least one device for measuring a characteristic of the cell selected from the group including but nct limited to: voltage, current, temperature and/or resistance, 47. A battery unit according to paragraph 46, wherein the battery unit further comprises a data storage means for receiving at least a portion of data received from the cell management system and wherein at least a portion of the cell monitoring system, electrical connectors arid data storage means is embedded within the enclosure, 48. A battery unit according to any one of paragraphs 33 to 47, wherein the battery unit comprises a compression member arranged to exert a compressive force along one face of the cell and wherein the dimensions of the enclosure are calculated such that the compression member is compressible to a known degree when the battery unit is in an assembled configuration and therefore exerts a known compressive force on the cell.
49. A battery unit according to any one of paragraphs 33 to 48, wherein the battery unit comprises a heat transfer plate arranged to absorb heat from the cell and interfaced with an external source to conduct excess heat away from the cell.
50. A battery module comprising a plurality of interconnected battery units according to any one of paragraphs 33 to 49.
51. A battery unit for exerting a known compressive force on a cell, the battery unit comprising: a cell for the storage and discharge of electrochemical energy; an enclosure configured and arranged to support and at least partially enclose the cell; and a resilient member arranged to at least partially abut one face of the cell, wherein the dimensions of the enclosure are predetermined to accommodate the cell and part of the resilient member, such that assembly of the battery unit results in compression of the resilient member to exert a predetermined force on the cell.
52. A battery unit according to paragraph 51, wherein the compressive fo-ce applied to a face of the cell is predetermined and adapted by modifying one or more of the following: dimensions of the enclosure, thickness of the resilient material and/or inherent compression force deflection characteristics of the resilient member.
53. A battery unit according to paragraph 51 or paragraph 52, wherein the resilient member comprises a foam pad.
54. A battery module comprising a plurality of interconnected battery units according to any one of paragraphs 51 to 53.
55. A battery module comprising: a plurality of battery units in adjacent relation, wherein each battery unit has electrical contact tabs extending therefrom in tvvo discrete rows enabling electrical interconnection of the battery units; and a plurality of monometallic connecting devices for electrically connecting selected tabs of the battery units.
56. A battery unit according to paragraph 55, wherein the monometallic connecting device has substantially the same metallurgy as outwardly extending parts of the cell tabs.
57. A battery module comprising: a plurality of battery units in adjacent relation, wherein each battery unit has electrical contact tabs extending therefrom in two discrete rows enabling electrical interconnection of the battery units; a plurality of connecting devices, each connecting device comprising elongate slots spaced and arranged for receiving selected electrical contact tabs.
58. A battery unit according to any one of paragraphs 55 to 57, \A/herein the connecting device comprises a substantially planar sheet.
59. A battery unit according to any one of paragraphs 55 to 58, \A/herein the connecting device comprises locator holes, to facilitate location of the connecting device relative to the electrical contact tabs and facilitate welding of the tabs and the connecting device.
60. A battery unit according to any one of paragraphs 55 to 57, wherein the connecting device comprises a sheet having a plurality of spaced parallel ridges extending from the sheet, with elongate tab receiving slots located in the apex of each ridge.
61. A battery unit according to paragraph 60, wherein electrical contact tabs received within tab receiving slots located in the ridges of the connecting device are pinched into contact with the connecting device thereby causing at least partial displacement of the tabs and/or adjacent ridges of the connecting device.
62. A battery unit according to any one of paragraphs 55 to 57, wherein the connecting device has a corrugated form comprising uniform loops having a pattern of parallel ridges and grooves, wherein elongate slots are provided in the ridges of the corrugated form for receiving the electrical contact tabs.
63. A battery unit according to paragraph 62, wherein alternate loops of the connecting device are arranged to receive electrical contact tabs, and wherein the connecting device is mechanically urged into contact with the tab allowing at least partial deformation of intermediate loops within the corrugated form to facilitate the contact between the tab and the connecting device without substantial displacement of the tabs.
64. A battery unit according to any one of paragraphs 55 to 57, wherein the connecting device includes a body portion having tab abutments that are substantially perpendicular to the body portion, wherein the tab abutments are arranged for substantially parallel contact with the electrical contact tabs to be connected.
65. A battery unit according to paragraph 64, wherein the connecting device comprises separate parts that are assembled To form parallel abutments on both sides of the electrical contact tabs, 66. A battery unit according to any one of paragraphs 55 to 65, wherein the connecting device is mechanically joined anc laser welded to the tabs allowing the electrical interconnection of the selectee] cells between battery units within the module.

Claims (30)

  1. Claims A battery unit comprising: a cell for the storage and discharge of electrochemical energy; a cell monitoring system associated with the cell and adapted to monitor at least one characteristic of the cell; a data storage means electrically connected to the cell monitoring system and adapted to store at least a portion of the data received from the cell monitoring system; and an enclosure configured and arranged to accommodate the cell monitoring system, data storage means and at least partially support the cell.
  2. 2. A battery unit according to claim 1, wherein the cell monitoring system includes a plurality of sensor elements to monitor one or more of the following characteristics associated with the cell: voltage, current, resistance and/or temperature.
  3. 3. A battery unit according to claim 1 or claim 2, wherein the cell monitoring system comprises at least one temperature sensor located proximate or on the surface of the cell wherein the at least one temperature sensor is electrically connected to the data storage 20 means.
  4. 4. A battery unit according to any of the preceding claims, wherein the cell monitoring system comprises a plurality of temperature sensors spaced at intervals along the surface of the cell, wherein each temperature sensor is electrically connected to the data storage means.
  5. 5. A battery unit according to any of the preceding claims, wherein the cell comprises a positive contact tab and a negative contact tab and wherein the cell monitoring system provides an electrical connection between the cell tabs and the data storage system for the measurement and recordal of voltage and/or internal resistance characteristics of the cell.
  6. 6. A battery unit according to any of the preceding claims, wherein the battery unit further comprises a contactless data transmitter electrically connected to the data storage means and arranged for the selective and remote transmission of data from the data storage means to an external source
  7. 7. A battery unit according to any of the preceding claims, wherein at least one of the cell monitoring system, electrical connectors and/or data management is at least partially embedded within the enclosure,
  8. 8. A battery unit according to any of the preceding claims, wherein the enclosure comprises at least one recessed aperture for accommodating the data storage means.
  9. 9. A battery unit according to any of the preceding claims, wherein the cell monitoring system and the data storage means are connected by electrical connectors embedded or integrated within the enclosure.
  10. 10. A battery unit according to any of the preceding claims wherein at least a portion of the data storage means and electrical connectors are encapsulated in a protective material selected to provide mechanical and environmental protection of the data storage means and/or electrical connectors.
  11. 11. A battery unit according to any of the preceding claims, wherein the battery unit further comprises a compression member arranged to act on the cell and exert a uniform compressive force thereon.
  12. 12. A battery unit according to claim 11, wherein the compression member has a substantially planar face that corresponds to a substantially planar face of the cell and wherein the compression member is accommodated alongside the cell within the enclosure, such that the planar face of the cell contacts the corresponding planar face of the compression member and wherein the compression member is accommodated within the assembled battery unit in a compressed configuration in which a known compressive force is exerted on the cell.
  13. 13. A battery unit according to claim 11 or claim 12, wherein the compression member comprises a resiliently deformable material and the dimensions of the enclosure are selected to accommodate the cell and the compression member only in a compressed configuration such that the cell is compressed by a known deflection in the assembled battery unit.
  14. 14. A battery unit according to any of the preceding claims, wherein the battery unit comprises a heat transfer member that is located alongside at least a portion of a planar face of the cell, wherein the heat transfer member is electrically isolated from the cell and arranged to transfer excess heat away from the cell.
  15. 15. A battery unit according to claim 14, wherein the heat transfer member comprises a heat transfer plate made from a thermally conductive material, and wherein the heat transfer plate acts as a backing plate for the battery unit.
  16. 16. A battery unit according to claim 1401 claim 15, wherein the heat transfer member comprises a channel allowing the circulation of a coolant within the channel in use.
  17. 17. A battery unit according to any of the preceding claims, wherein the battery unit comprises locator keys associated with the enclosure and the cell, wherein the locator keys constrain orientation of the cell within the enclosure in the assembled battery unit thereby ensuring the cell is in the correct orientation with respect to predetermined polarity.
  18. 18. A battery unit according to claim 17, wherein the locator keys comprise different moulded features provided on the enclosure, each moulded feature having a corresponding receiving aperture located on a respective cell tab, such that the cell is constrained to the preselected orientation within the enclosure to enable assembly of the battery unit.
  19. 19. A battery unit according to any of the preceding claims, wherein the battery unit comprises two tab retainers for retaining the -abs of the cell, wherein each tab retainer is cooperatively engageable with the enclosure in one position and wherein the tab retainers comprise a visual identification of polarity such that the preselected tab retainer is only engageable with the enclosure over the associated tab with specific polarity thereby providing a reliable visual identification of tab polarity,
  20. 20. A battery unit according to any preceding claim, wherein the cell comprises a positive contact tab and a negative contact tab, the contact tabs enabling the interconnection of the battery unit to an external source and wherein one of the contact tabs comprises a bimetallic strip.
  21. 21. A battery unit according to claim 20, wherein the bimetallic strip has one end formed form a second metal for internal electrical contact within the cell tab and another end that extends outwardly from the cell formed from a first metal, and wherein the other contact tab is monometallic and formed from the first metal such that outwardly extending ends of both tabs are formed from the same metal.
  22. 22. A battery module comprising a plurality of interconnected battery units according to any one of claims.] to 21.
  23. 23. A battery module according to claim 22, comprising connecting devices for electrically connecting selected tabs of adjacent battery units, wherein battery units are arranged such that the polarity of adjacent cell tabs is in a preselected orientation and connecting devices of a required length are electrically connected to the tabs in the desired orientation.
  24. 24. A battery module according to claim 23, wherein each connecting element has elongate slots for receiving cell tabs and whe'ein tabs are pinched into contact with the connecting device within the tab receiving slot.
  25. 25. A battery module according to claim 23 or claim 24, wherein the connecting device is monometallic and formed from a same metal as the outwardly extending portion of each cell tab
  26. 26. A battery module according to any one of claims 22 to 25, when dependent on any of claims 14 to 16, wherein the battery module comprises a module cooling arrangement to substantially restrict overheating of the module in use, wherein the module cooling arrangement comprises at least one cooling plate that interfaces with thermal transfer member of each battery unit.
  27. 27. A battery module according to claim 26, wherein the module cooling arrangement comprises at least one plate having a channel allowing the circulation of a coolant within the channel in use and wherein the at least one cooling plate acts as a backing plate for the module.
  28. 28. A battery module according to any one of claims 22 to 27, wherein the battery module comprises a compression mechanism for applying a compressive force to stacked battery units within the module.
  29. 29. A structure comprising one or more battery units according to any of claims 1 to 21 for stationary applications.
  30. 30. A movable entity comprising one or more battery units according to any of claims 1 to 21 for mobile applications.
GB2108368.8A 2021-06-11 2021-06-11 Battery unit Pending GB2607882A (en)

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CN116470189B (en) * 2023-06-01 2023-08-18 天津提尔科技有限公司 Submerged battery thermal management system

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