# Patent

## Title
Low magnetic interference battery

## Abstract

A low magnetic interference battery is provided, the battery insertable into a mobile communication device, the mobile communication device comprising a radio interconnected with a microphone and a receiver. The battery comprises a battery portion enabled to provide electrical power to the radio, the battery portion emitting a magnetic field when in operation. The battery further comprises a sealing portion for sealing the battery portion therein such that the battery portion is protected from moisture, the sealing portion comprising a magnetic shield portion arranged relative to the battery portion such that magnetic flux from the battery portion is routed away from the receiver when the battery is in operation in the mobile communication device.

## Background
RELATED APPLICATIONS
This patent application is a continuation of U.S. patent application Ser. No. 12/752,705, filed Apr. 1, 2010, which claims the benefit of U.S. Provisional Application No. 61/225,364, filed Jul. 14, 2009, both of the applications are hereby incorporated by reference in their entirety.


TECHNICAL FIELD
The present disclosure relates generally to batteries and more particularly to a battery characterized by low magnetic interference.
BACKGROUND
Mobile communication devices are popular for business and personal use. Such devices include Personal Digital Assistants (PDAs), cellular phones and smart phones. These devices provide wireless two-way voice and data communication over wireless networks such as GSM/GPRS, CDPD, TDMA, iDEN Mobitex, DataTAC, EDGE or UMTS networks, and broadband networks like Bluetooth and variants of 802.11.
It is desirable that the electromagnetic fields generated by such devices be minimized for health reasons and in order to reduce interference with other nearby electronic devices. For example, international standards on Hearing Aid Compatibility (HAC) establish a minimum signal-to-noise (SNR) ratio at the T-coil of a hearing aid (for example, see section 7.3.4 “Signal Quality” of ANSI C63.19-2007) for effective magnetic wireless coupling to the hearing aid (including hearing aids, cochlear implants, and assistive listening devices) while minimizing magnetic interference. The hearing aid compatibility requirements are generally evaluated with the hearing aid coil in close proximity to the receiver in the mobile communication device. Traditional approaches to meeting the required signal-to-noise ratio in the presence of magnetic fields generated by mobile communication devices include increasing current in the mobile communication device receiver, installing a separate T-coil within the mobile communication device, and altering current loops and circuit board traces within the mobile communication device to minimize magnetic interference.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram illustrating a wireless mobile communication device in accordance with the present disclosure;
FIG. 2 is a perspective view of a conventional battery for powering the wireless mobile communication device of FIG. 1;
FIG. 3A is a schematic representation of positive and negative electrodes of a prior art battery such as that shown in FIG. 2, in an un-rolled configuration;
FIG. 3B is a schematic representation of positive and negative electrodes of a prior art battery such as that shown in FIG. 2, in a rolled-up configuration;
FIG. 4 is a schematic representation of positive and negative contact pads of a prior art battery such as that shown in FIG. 2;
FIG. 5 is a schematic representation of a cross section of a side view of a prior art battery emitting magnetic flux in operation;
FIG. 6 is a schematic representation of a cross section of a prior art wireless mobile communication device powered by a prior art battery therein, and further depicting magnetic flux emitted from the battery;
FIG. 7a is a schematic representation of a cross section of a battery incorporating a battery portion and a magnetic shield portion;
FIG. 7b is a schematic representation of a perspective view of a battery incorporating a battery portion and a magnetic shield portion;
FIG. 8 is a schematic representation of a cross section of a wireless mobile communication device powered by the battery of FIGS. 7a and b, and further depicting magnetic flux emitted from the battery;
FIG. 9 comprises FIGS. 9a and 9b and is a schematic representation of a cross section of a wireless mobile communication device incorporating a magnetic shield portion;
FIG. 10 is a schematic representation of a side view of a battery incorporating a battery portion and a magnetic shield portion, the magnetic shield portion encompassing the battery portion;
FIGS. 11a and 11b are schematic representations of a model of a current loop representative of a battery in a mobile communication device;
FIGS. 12a and 12b are schematic representations of a model of a current loop representative of a battery in a mobile communication device with a magnetic shield portion in place;
FIG. 13 is a schematic representation of a cross section of a prior art battery incorporating structural elements;
FIG. 14 is a schematic representation of a cross section of a battery incorporating a magnetic shield portion and a structural element, the magnetic shield portion also providing structural support;
FIG. 15 is a schematic representation of a cross section of a battery incorporating two magnetic shield portions, each magnetic shield portion also providing structural support;
FIG. 16 comprises a schematic representation of a cross section of a prior art battery, a battery portion of the battery sealed inside a sealing portion;
FIG. 17 comprises a schematic representation of a cross-section of a battery, wherein a sealing portion comprises a magnetic shield portion;
FIG. 18 comprises a schematic representation of a cross-section of a battery, wherein a sealing portion comprises a magnetic shield portion;
FIG. 19 comprises a schematic representation of a cross section of a prior art battery, a battery portion of the battery sealed inside a soft sealing case;
FIG. 20 comprises a schematic representation of a cross-section of a prior art soft sealing case;
FIG. 21 comprises a schematic representation of a cross-section of a battery, a battery portion of the battery sealed inside a soft sealing case incorporating a magnetic shield portion;
FIG. 22 comprises a schematic representation of a cross section of the soft sealing case of FIG. 21, according to non-limiting embodiments; and
FIG. 23 comprises a schematic representation of a cross section of the soft sealing case of FIG. 21, according to non-limiting embodiments.



DETAILED DESCRIPTION
Magnetic noise may be generated by a battery of a mobile communication device due to current draw associated with GSM radio transmission. Accordingly, it is desirable to minimize magnetic interference from mobile communication devices in general and to minimize magnetic interference from mobile communication device batteries due to current draw on the battery.
An aspect of the specification provides a battery, insertable into a mobile communication device, the mobile communication device comprising a radio interconnected with a microphone and a receiver. The battery comprises a battery portion enabled to provide electrical power to the radio, the battery portion emitting a magnetic field when in operation. The battery further comprises a sealing portion for sealing the battery portion therein such that the battery portion is protected from moisture, the sealing portion comprising a magnetic shield portion arranged relative to the battery portion such that magnetic flux from the battery portion is routed away from the receiver when the battery is in operation in the mobile communication device.
The sealing portion can comprise a rigid sealing can, providing structural stability to the battery. At least a portion of the sealing can comprise a high magnetic permeability material such that the magnetic shield portion is structurally incorporated into the sealing can. The sealing can comprise a can portion, for containing the battery portion therein, and a plate portion, attached to the can portion, for sealing the battery portion in the sealing can.
The magnetic shield portion can comprise a coating on the sealing portion.
The sealing portion can comprise a soft sealing case. The soft sealing case can comprise at least one flexible layer of insulating material and at least one flexible layer of high magnetic permeability material, such that the magnetic shield portion is integrated into the soft sealing case via the at least one flexible layer of high magnetic permeability material, the soft sealing case further comprising a layer of the insulating material on a battery portion side of the soft sealing case. The soft sealing case can further comprise at least one flexible layer of metal foil.
The magnetic shield portion can comprise Mu Metal.
The battery can further comprise connectors to the battery portion through the sealing portion.
A discussion of the prior art and exemplary embodiments follow hereafter with reference to the drawings.
FIG. 1 is a block diagram illustrating some of the components of a wireless mobile communication device 130. In the embodiment depicted in FIG. 1, wireless mobile communication device 130 includes a communication subsystem 200 for wireless two-way data and voice communication with the wireless network 120. Communication subsystem 200 may include one or more receivers, transmitters, antennas, signal processors and other components associated with wireless communications including but not limited to a radio 201. The particular design of the communication subsystem 200 can depend on the network in which the wireless mobile communication device 130 is intended to operate. The concepts herein may be applicable to a variety of wireless mobile communication devices, such as two-way pagers, cellular telephones, etc.
In the embodiment shown in FIG. 1, network access is associated with a subscriber or user of the wireless mobile communication device 130 via a memory module 202, which may be a Subscriber Identity Module (SIM) card for use in a GSM network or a Universal Subscriber Identity Module (USIM) card for use in a Universal Mobile Telecommunication System (UMTS). The SIM card is inserted in or connected to an interface 204 of the wireless mobile communication device 130 to operate in conjunction with the wireless network 120. Alternatively, the wireless mobile communication device 130 may have an integrated identity module for use with systems such as Code Division Multiple Access (CDMA) systems.
The wireless mobile communication device 130 also includes a battery interface 206 for receiving at least one rechargeable battery 208. The battery 208 provides electrical power to at least some of the electrical circuitry in the wireless mobile communication device 130, and the battery interface 206 provides a mechanical and electrical connection for the battery 208. As discussed above and in greater detail below, it has been discovered that when the mobile communication device 130 is held in close proximity to a hearing aid device (as is the case during normal cell phone usage, for example when a receiver 224 is held close to a hearing aid device) the time waveform (and frequency spectrum) of the Radio Frequency (RF) amplifier current within communication subsystem 200 is largely the same as that of the measured magnetic noise at the hearing aid coil. This indicates that interference problems with the hearing aid result from magnetic noise generated by currents within the communication system associated with GSM radio transmission. Through subsequent measurements and analysis, it was found that a large portion of this magnetic noise was generated by the battery, though magnetic noise can be generated by other components of the communication device 130.
The communication device 130 also generally includes radio 201 (e.g. within the communication subsystem 200), a microphone 226 and the receiver 228. The receiver 228 can include, but is not limited to, a voice coil, a hearing aid coil and a separate T-coil.
The wireless mobile communication device 130 may include one or more circuit boards (not shown) that implement the components described above. This disclosure is not limited to any particular electronic component or software module or any combination thereof.
FIG. 2 shows a conventional battery 208 for powering a mobile communication device 130. The battery is assembled inside a case 240 and includes a positive contact pad 250, a negative contact pad 260, and may include a temperature contact pad 270 and a cryptography contact pad 280 for testing manufacturer's authenticity of the battery 208. Although not shown, the battery may include an internal microprocessor and a switch in series with the contact pads 250 and 260 which is opened by the internal microprocessor if the battery discharges below a predetermined level, in order to avoid damage to the battery. Likewise, if the battery temperature elevates beyond a predetermined level, as indicated on the temperature contact pad 270, the microprocessor may cause the switch to open.
A sandwich electrode assembly is located within the case 240, comprising coated metallic films that according to the most common configurations are either stacked, folded back and forth like an accordion (referred to as a Z-type electrode assembly), or rolled up and flattened (referred to as a “jellyroll” electrode assembly). Reference will be made hereinafter to the construction and design of “jellyroll” electrode assemblies, although a person of skill in the art will appreciate that the principles set forth herein apply equally to other designs and configurations of electrode assemblies.
One such “jellyroll” electrode assembly 300 is schematically represented in FIG. 3A in its un-rolled state and in FIG. 3B in its final rolled-up state. The exemplary prior art electrode assembly 300 comprises a positive electrode sheet 310 (cathode) and a negative electrode sheet 320 (anode) sandwiched together with a separator sheet 330 between them, and a further outer separator sheet 340 that may curl around the end of the positive electrode sheet 310 at the innermost section of the jellyroll so as to completely isolate the positive and negative electrodes. The separator sheet 330 contains an electrolyte, such as lithium salts, such as LiPF6, LiBF4, or LiClO4, in an organic solvent, such as ether. The electrolyte may also be acid such as in a lead-acid battery, alkaline electrolyte usually potassium hydroxide in a nickel metal hydride or nickel cadmium. The positive electrode sheet 310 may comprise a thin sheet of aluminum (e.g. 15 μm) that is coated on both sides (e.g. 60-70 μm per side) with Lithium cobalt oxide (LiCoO2), or other suitable material, while the negative electrode sheet 320 may comprise a thin sheet of copper foil (e.g. 10 μm) that is coated on both sides with graphite (e.g. 60-70 μm per side), such that electrical current flows from the cathode to the anode. The separator sheet 330 (e.g. 20 μm) has openings in it that allow the electrolyte liquid to permeate between the positive and negative electrode sheets 310 and 320. The separator sheet 330 thus physically separates the two electrode sheets while allowing ions to flow between them. Additional details of the construction of a conventional jellyroll electrode assembly may be found in the prior art, as exemplified by U.S. Pat. No. 7,488,553 (Tsukamoto et al).
Electrical connection between the negative electrode sheet 320 and battery contact pad 260 may be made via a conducting tab 362 that extends to an insulated feed-through (for example, as discussed below and shown schematically in FIG. 6) which connects to a conductive strip 360 that is insulated from the case by an insulator 370 and which extends from the feed-through to the battery contact pad 260, as shown in FIG. 4. Electrical connection between the positive electrode sheet 310 and battery contact pad 250 may be made either by leaving the aluminum electrode uncoated in its last roll of the jellyroll structure so as to expose the bare aluminum electrode and spot-welding, or crimping the last roll of the electrode 310 to the conductive case 240, or by spot-welding or crimping a conducting tab 352 to the case 240, thereby forming an external connection to the positive electrode through the case. A further conductive strip 350 may be spot-welded to an opposite side of the case from the spot-welded tab 352, or last roll of positive electrode sheet, which extends from the spot-weld on the case 240 to the battery contact pad 250, as shown in FIG. 4. In such an arrangement, the positive connection to outside of the case 240 is made on the opposite side of the battery case to the negative connection, as shown in FIG. 3B. However, it is also known in the art for the positive and negative connections to outside of the case 240 to be on the same side.
Power is typically provided from the battery 208 to a device, such as communication device 130, via conducting pads (260, 250), as discussed above. As shown in FIG. 4, a strip of conductor 350 carries the current from the conductive case 240 to the positive pad 250. The connection from the negative feed-through to conductive strip 360 is made on the opposite side of the battery from the positive connection. The conductive strip 360 carries the current from the feed-through to the negative pad 260. It will be appreciated that the arrangement of FIG. 4 results in large currents flowing externally of the battery case 240.
As shown in FIGS. 3A and 3B, if the connections 352 and 362 to the electrodes are made at opposite ends of the electrode assembly 300, i.e., one connection is made on the center of the jellyroll and the other on the outside of the jellyroll, current flow within the positive and negative electrode sheets 310 and 320 is in the same direction. Moreover, the magnitude of the electrode current increases from zero at the end opposite the connection to maximum at the end with the connection. Therefore, the magnitude of the current in the two electrodes as a function of position is significantly different.
Sources of magnetic noise in the prior art battery design of FIGS. 3 and 4 include noise from the electric currents flowing in the jellyroll electrode assembly 300 and ion current in the electrolyte liquid, the connections from the electrodes 310, 320 to the feed-throughs, currents flowing in the battery case 240 and the external conductive strips 350, 360.
FIG. 5 depicts a cross-section of a battery 508, similar to battery 208, comprising a case 540 containing a battery portion 509, which in some embodiments is similar to the “jellyroll” described above with reference to FIG. 3b. FIG. 5 further depicts the magnetic flux 510 emitted from the battery 508 when it is in operation (for example when inserted into the battery interface 206 of communication device 130, as depicted in FIG. 6). It is understood that the battery portion 509 is the source of the magnetic flux 510. Indeed, FIG. 6 depicts the battery 508 inserted into the battery interface 206, with magnetic flux 510 passing through, and in the general area of, the receiver 224, such that when the receiver 224 is held adjacent to a hearing aid, the magnetic flux 510 will interfere with the operation of the hearing aid by decreasing the SNR of the hearing aid (e.g. noise will increase).
It is furthermore understood that depictions of magnetic flux in FIG. 5, as well as in FIGS. 6, 7a, 8, 10, 13, 14, 15, 16, 17, 18, 19 and 21 are approximations. Modeling of magnetic flux from a battery is provided in FIGS. 11a and 11b, described below. Modeling of magnetic field from a battery with magnetic shield in place is provided in FIGS. 12a and 12b, described below.
As described in detail below, magnetic noise may be significantly reduced (e.g. >10 dB reduction over the prior art) by providing a magnetic shield to direct the magnetic flux 510 away from the region of the receiver 224. In some embodiments, as depicted in a schematic cross-section in FIG. 7a, a battery 708 is provided which comprises a battery portion 710, similar to battery 508 with like elements having like numbers, though starting with “7” rather than “5” (e.g. case 740 is similar to case 540), and a magnetic shield portion 712. The magnetic shield portion 712 generally comprises a high magnetic permeability material, including but not limited to Mu Metal, however other materials of suitable magnetic permeability are within the scope of present embodiments. Furthermore, the magnetic shield portion 712 is arranged relative to battery portion 710 so that the magnetic flux 510′ is generally routed through the magnetic shield portion 712 such that when the battery 708 is inserted into the battery interface 206 of the communication device 130, and the battery 708 is in operation, the magnetic flux 510′ is generally routed away from the receiver 224. Hence, in general, at least some portion of magnetic shield portion 712 is oriented such that a normal 713 of the magnetic shield portion 712 is generally aligned in the direction of the receiver 224 when the battery 708 is inserted into the battery interface 206.
It is understood that while in FIG. 7 the magnetic shield portion 712 is external to outside to the case 740, in other embodiments the magnetic shield portion 712 can be internal to the case 740 (e.g. located between the battery portion 710 and the case 740), for example see FIGS. 14 and 15.
The thickness and geometry of the magnetic shield portion 712 can be dependent on the geometry of the magnetic flux 510′, and the position of the receiver 224 relative to the battery 708 when inserted into the battery interface 206. Indeed, the thickness and geometry of the magnetic shield portion 712 can be optimized using the equations of magnetostatics:




  
    
      
        
          
            ∇
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              where
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        (
        
          Equation
          ⁢
          
            
          
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          Set
          ⁢
          
            
          
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          1
        
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whereby B is magnetic flux density, H is magnetic field intensity, c is the speed of light, j is current density and μ is magnetic permeability. Equation Set 1 is then generally solved with the boundary conditions:





  
    
      
        
          
            
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                1
              
            
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whereby B1 and B2 are the magnetic flux density in, respectively, a first medium 1 and an adjacent second medium 2 (e.g. medium 1 comprises the medium outside the magnetic shield portion 712 and medium 2 comprises the material of the magnetic shield portion 712, such as Mu metal); n is the normal of the interface between medium 1 and medium 2; and μ1 and μ2 are the magnetic permeabilities of medium 1 and medium 2, respectively. These equations can be solved using any suitable software, including commercially available software.

FIG. 7b depicts a perspective view of block diagram battery 708, including the battery portion 710 and the magnetic shield portion 712. For clarity, the case 740 is not depicted in FIG. 7b, though it is understood that magnetic shield portion 712 can be either internal or external to the case 740. While in FIGS. 7a and 7b, the magnetic shield portion 712 is depicted as having the same general area of the battery portion 710, it is understood that the magnetic shield portion 712 can be smaller or larger than the area of the battery portion 710, as desired, as long as there is an overall reduction in magnetic flux in the area of the receiver 224 when the battery 708 is in operation in the communications device 130 (see FIG. 8 below). Furthermore, while in FIGS. 7a and 7b, magnetic shield portion 712 is depicted as being incorporated on a face of the battery portion 710 and/or the case 740, this is not to be considered particularly limiting; indeed, as described above, the magnetic shield portion 712 can be located internal or external to the case 740.
Turning now to FIG. 8, when battery 708 is inserted in battery interface 206 of communication device 130, the magnetic flux 510′ is directed away from the general area of the receiver 224, hence reducing interference with a hearing aid adjacent to receiver. Hence, it is understood that magnetic shield portion 712 is arranged on a side of the battery portion 710 which, when inserted into communication device 130, is generally facing the receiver.
In alternative non-limiting embodiments, as depicted in FIG. 9a, a magnetic shield portion 912, similar to magnetic shield portion 712, is incorporated into communication device 130. The magnetic shield portion 912 is generally located between the battery interface 206 and the receiver such that at least one normal of the magnetic shield portion 912 is pointing in a direction of a magnetic field emitted from a battery (not depicted) inserted into battery interface 206 when the battery is in operation in the communication device 130. Hence, magnetic flux will be conducted away from the receiver 224 when the battery is in operation, as in FIG. 7.
While in FIG. 9 the magnetic shield portion 912 is depicted as having the same general area of battery interface 206, it is understood that the area of the magnetic shield portion 912 can be smaller or larger than the area of the battery interface 206, as desired, as long as there is an overall reduction in magnetic flux in the area of the receiver 224. Furthermore, while in FIG. 9, magnetic shield portion 912 is depicted as being incorporated into battery interface 206, this is not to be considered particularly limiting; indeed, the magnetic shield portion 912 can be located in any suitable part of communication device 130, between the battery interface 206 and receiver. For example, as depicted in FIG. 9b, a magnetic shield portion 912′ can be incorporated into the body of the communication device 130.
It is further understood that embodiments such as that depicted in FIG. 9b shield the area of the receiver 224 not only from magnetic flux emitted from a battery inserted into the battery interface 206, but from other sources of magnetic interference within the communication device 130.
Attention is now directed to FIG. 10, which depicts alternative non-limiting embodiments of a battery 1008, similar to battery 708, with like elements having like numbers, however starting with “10” rather than “7”. However, in these embodiments, the magnetic shield portion 1012 comprises a plurality of interconnected planes 1090a, 1090b, 1090c, 1090d, each having a respective normal 1013a, 1013b, 1013c, 1013d, such that the battery portion 1010 is generally encompassed by the magnetic shield portion 1012. While only four of the interconnected planes are depicted in FIG. 10, it is understood that each side of the battery portion 1010 is associated with a respective plane of the magnetic shield portion 1012. In other words, if the battery portion 1010 is generally a rectangular box, then the magnetic shield portion 1012 is also a generally rectangular box of proportions similar to the battery portion 1010, however with apertures there through for electrodes 1050, 1060, 1070 and 1080. Hence, magnetic flux 510′′ emitted from the battery portion 1010 when in operation, is now largely contained within the magnetic shield portion 1012.
Attention is now directed to FIGS. 11a and 11b, which depict magnetic field lines of a model of a current loop 1110 of radius 0.05, according to non-limiting embodiments. FIG. 11b is similar to FIG. 11a, but depicts only the right hand side of FIG. 11a. It is understood that each of FIGS. 11a and 11b have been modeled with arbitrary units. It is furthermore understood that the current loop depicted in FIGS. 11a and 11b can be used to model the battery 508.
Attention is now directed to FIGS. 12a and 12b, which are similar to FIGS. 11a and 11b, respectively, however each of the models depicted in FIGS. 12a and 12b include a magnetic shield portion 1212a and 1212b, respectively, each similar to magnetic shield portions 712, 912, 1012 described above. Furthermore, the magnetic permeability of the magnetic shield portion 1212b being greater than the magnetic permeability of the magnetic shield portion 1212a. In any event, from a comparison of FIGS. 11a and 11b, it is understood that there is a reduction in magnetic flux to the right of the magnetic shield portion 1212a. FIGS. 11a and 12a are understood to represent a communication device, with the current loop 1110 representative of a battery in the communication device, and the magnetic shield portion 1212a representative of a magnetic shield portion in the communication device. FIG. 11a represents the communication device without a magnetic shield portion and FIG. 12a represents the communication device with a magnetic shield portion. Hence, from a comparison of FIGS. 11a and 12a, it is understood that a receiver of the communication device located to the right of the magnetic shield portion 1212a would experience a reduction in magnetic flux with the magnetic shield portion when compared to a communication device without the magnetic shield portion 1212a. Similarly, it is understood that a similar reduction in magnetic flux is present between FIGS. 11b and 12b; furthermore, from a comparison of FIGS. 12a and 12b, it is understood that by increasing magnetic permeability of a magnetic shield portion, the magnetic flux can be further reduced (i.e. the magnetic flux to the right of the magnetic shield portion 1212b is less than the magnetic flux to the right of the magnetic shield portion 1212a).
Attention is now directed to FIG. 13, which depicts a battery 1308, similar to the battery 508 depicted in FIG. 5, with like elements having like numbers, however preceded by a “13” rather than a “5”. For example, the battery 1308 comprises a case 1340 similar to the case 540. However, the battery 1308 further comprises structural elements 1350a and 1350b. For example, in some embodiments, the case 1340 can be comprised primarily of plastic. Hence to give the battery 1308 structural stability, for example to meet ruggedness testing, the structural elements 1350a, 1350b can comprise plates made from any suitable metal, such as stainless steel and aluminum, and are of a suitable thickness to provide structural stability to the battery 1308. In general, each structural element 1350a and 1350b can be the same or different thicknesses, as desired. It is understood that the structural elements 1350a, 1350b generally sandwich the battery portion 1309 inside the case 1340. FIG. 13 further depicts magnetic flux 1310, similar to the magnetic flux 510, emitted from the battery portion 1309, when the battery 1308 is in operation. Similar to the description of the battery 508 described above, the magnetic flux 1310 from the battery 1308 can interfere with operation of a hearing aid, by decreasing the SNR of the hearing aid (e.g. noise will increase), when the battery 1308 is in operation in the mobile communication device 130, and the receiver 224 is held adjacent to the hearing aid.
Attention is now directed to FIG. 14, which depicts a battery 1408, similar to the battery 1308, with like elements having like numbers, however preceded by a “14” rather than a “13”. For example, the battery 1408 comprises a case 1440 similar to the case 1340. However the battery 1408 includes a first structural element 1450, similar to the structural element 1350a, and a magnetic shield portion 1412. Magnetic shield portion 1412 is similar to structural element 1350b, however magnetic shield portion 1412 generally comprises a high magnetic permeability material, similar to the magnetic shield portion 712. The high magnetic permeability material can include, but is not limited to, Mu Metal, and it is understood that other materials of suitable magnetic permeability are within the scope of present embodiments. Furthermore, the magnetic shield portion 1412 is on a side of the battery portion 1409 such that the magnetic flux 1410 is generally routed through the magnetic shield portion 1412 such that when the battery 1408 is inserted into the battery interface 206 of the communication device 130. In other words, when the battery 1408 is in operation, the magnetic flux 1410 is generally routed away from the receiver 224, similar to the battery 708.
Furthermore, the magnetic shield portion 1412 provides structural stability to the battery 1408, similar to the structural element 1350b, and hence the magnetic shield portion 1412 can comprise a plate made from any suitable high magnetic permeability metal, such as Mu Metal, and is of a suitable thickness to provide structural stability to the battery 1408. It is hence understood that the structural element 1450 and the magnetic shield portion 1412, generally sandwich the battery portion 1409 inside the case 1440. Hence, in general, structural element 1450 and the magnetic shield portion 1412 provide similar structural functionality to the battery 1408 as the structural element 1350a and 1350b in the battery 1308, however the magnetic shield portion 1412 further routes the magnetic flux away from the receiver 224 when the battery 1408 is in operation in the mobile communication device 130. In general, it is further understood that each of the magnetic shield portion 1412 and structural element 1450 can be the same or different thicknesses, as desired.
Attention is now directed to FIG. 15, which depicts a battery 1508, similar to the battery 1408, with like elements having like numbers, however preceded by a “15” rather than a “14”. For example, the battery 1508 comprises a case 1540 similar to the case 1440. However the battery 1508 includes a first magnetic shield portion 1512a, similar to the magnetic shield portion 1412, and a second magnetic shield portion 1512b, similar to magnetic shield portion 1412. Magnetic shield portions 1512a and 1512b are similar to structural elements 1350a and 1350b, respectively, each of magnetic shield portions 1512a and 1512b generally comprises a high magnetic permeability material, similar to the magnetic shield portion 712. The high magnetic permeability material can include, but is not limited to, Mu Metal, and it is understood that other materials of suitable magnetic permeability are within the scope of present embodiments. Furthermore, the magnetic shield portions 1512a is on a side of the battery portion 1509 such that the magnetic flux 1510 is generally routed through the magnetic shield portion 1512a such that when the battery 1508 is inserted into the battery interface 206 of the communication device 140. In other words, when the battery 1508 is in operation, the magnetic flux 1510 is generally routed away from the receiver 224, similar to the battery 708. However, as the magnetic shield portion 1512b also comprises a high magnetic permeability material, the magnetic flux 1510 is also routed through the magnetic shield portion 1512b. In general, as magnetic shield portions 1512a and 1512b sandwich the battery portion 1509, a significant portion of the magnetic flux 1510 is generally contained within the battery 1508.
Furthermore, each of the magnetic shield portions 1512a and 1512b provides structural stability to the battery 1508, similar to the structural elements 1350a and 1350b, and hence each of the magnetic shield portions 1512a and 1512b can comprise a plate made from any suitable high magnetic permeability metal, such as Mu Metal, and are each of a suitable thickness to provide structural stability to the battery 1508. In general, it is further understood that each of the magnetic shield portions 1512a and 1512b can be the same or different thicknesses, as desired. As it is further understood that the magnetic shield portions 1512a and 1512b generally sandwich the battery portion 1509 inside the case 1540, the magnetic shield portions 1512a and 1512b provide similar structural functionality to the battery 1508 as the structural element 1350a and 1350b in the battery 1308, however the magnetic shield portions 1512a and 1512b further route the magnetic flux away from the receiver 224 when the battery 1508 is in operation in the mobile communication device 140.
Attention is now directed to FIG. 16, which depicts a cross-section of a battery 1608, similar to battery 508 of FIG. 5, with like elements having like numbers, however preceded by “16” rather than “5”. For example, the battery 1608 comprises a case 1640 similar to case 540. In general, the case 1640 contains a battery portion 1609, which in some embodiments is similar to the “jellyroll” described above with reference to FIG. 3b. Further, the battery portion 1609 is sealed inside a sealing can 1645. The sealing can 1645 comprises a can portion 1646 and a sealing plate portion 1647, the sealing plate portion 1647 sealed to the can portion 1646 such that the battery cell 1609 is sealed inside the sealing can 1645 within case 1640. The sealing plate portion 1647 can be sealed to the can portion 1646 using any suitable method, including but not limited to welding and glue. Furthermore, the at least one of the can portion 1646 and the plate portion 1647 can comprise apertures and/or electrical connectors for making electrical connection to the battery portion 1609. The sealing can 1645 can comprise any suitable metal, including but not limited to aluminum, and further can be of any suitable thickness. The sealing can 1645 can further comprise suitable apertures (not depicted) for tabs of the battery portion 1609, similar to tabs 352, 362 of FIG. 3B, such that electrical contact can be made to the battery portion 1609. It is understood that the sealing can 1645 protects the battery cell 1609 against moisture, and can further provide structural support for the battery 1608.
FIG. 16 further depicts the magnetic flux 1610 emitted from the battery 1608 when it is in operation (for example when inserted into the battery interface 206 of communication device 130, similar to the battery 508 and communication device 130 as depicted in FIG. 6). It is understood that the battery portion 1609 is the source of the magnetic flux 1610. As in FIG. 6 when the battery 1608 is inserted into the battery interface 206, the magnetic flux 1610 passes through, and in the general area of, the receiver 224, such that when the receiver 224 is held adjacent to a hearing aid, the magnetic flux 1610 will interfere with the operation of the hearing aid by decreasing the SNR of the hearing aid (e.g. noise will increase).
Attention is now directed to FIG. 17, which depicts a schematic cross-section of a battery 1708, similar to battery 1608 of FIG. 16, with like elements having like numbers, however preceded by “17” rather than “16”. For example, the battery 1708 comprises a sealing can 1745 similar to sealing can 1645, however sealing can 1745 comprises a magnetic shield portion 1712, which has a similar functionality to the magnetic shield portion 712, in that the magnetic flux 1710 from the battery portion 1709 is routed through the magnetic shield portion 1712 in order to route the magnetic flux 1710 away from the receiver 224 when the battery 1708 is in operation in communications device 130. In the depicted embodiment, the magnetic shield portion is located on a face of the sealing can 1745 which faces a receiver side of the communications device 130 when the battery 1708 is inserted into communications device 130.
In some embodiments, the magnetic shield portion 1712 can comprise a plate of a suitable high magnetic permeability material, including but not limited to Mu Metal, attached to a face of the sealing can 1745. In other embodiments, the magnetic shield portion 1712 can comprise a coating of a suitable high magnetic permeability material, using any suitable coating technique, including but not limited to plating techniques, spray coating methods, heating adhesion coating methods, chemical deposition methods, and the like. In some embodiments, other portions of the sealing can 1745 can be coated with high magnetic permeability material, including both the can portion 1746 and the sealing plate portion 1747. In some embodiments, the entire sealing can 1745 can be substantially coated with a high magnetic permeability material, such that magnetic flux is largely contained within the battery 1708, for example see FIG. 18.
Attention is now directed to FIG. 18, which depicts a schematic cross-section of a battery 1808, similar to battery 1708 of FIG. 17, with like elements having like numbers, however preceded by “18” rather than “17”. For example, the battery 1808 comprises a sealing can 1845 similar to sealing can 1745, however the sealing can 1845 comprises a high magnetic permeability material, including but not limited to Mu Metal. In other words, the sealing can 1845 is manufactured from Mu Metal (and the like), rather than aluminum or stainless steel. Hence, in addition to sealing the battery portion 1809, and providing structural stability for the battery 1809, the sealing can 1845 also functions as a magnetic shield, similar to magnetic shield 1012 depicted in FIG. 10, however, located inside case 1840 and further providing structural support and battery portion sealing functionality.
While in the embodiment depicted in FIG. 18, both the can portion 1846 and the sealing plate portion 1847 comprise a high magnetic permeability material, in yet further embodiments, one of the can portion 1846 and the sealing plate portion 1847 can comprise a high magnetic permeability material, while the other of the can portion 1846 and the sealing plate portion 1847 comprises another material, such as aluminum, stainless steel, and the like. In each of these embodiments, the element (i.e. one of the can portion 1846 and the sealing plate portion 1847) that comprises the high magnetic permeability material routes the magnetic flux away 1810 from the receiver 224 when the battery 1808 is in operation in communication device 130.
Attention is now directed to FIG. 19, which depicts a schematic cross-section of a battery 1908, similar to battery 1608 of FIG. 16, with like elements having like numbers, however preceded by “19” rather than “16”. For example, the battery 1908 comprises a soft sealing case 1945, the battery portion 1909 sealed inside the soft sealing case 1945. FIG. 20 depicts a schematic cross-section of the soft sealing case 1945: the soft sealing case 1945 can comprise layers of flexible insulating material 2010 and flexible foil 2020. The insulating material 2010 can comprise any suitable insulating material, including but not limited to polymers, of any suitable thickness; the foil 2020 can be of any suitable metal, including but not limited to aluminum, of any suitable thickness. Furthermore, the soft sealing case 1945 can comprise any suitable number of layers of insulating material 2010 and foil 2020, in any suitable order, such that the soft sealing case 1945 protects the battery portion 1909 from moisture. For example, while in FIG. 20, the soft sealing case 1945 is depicted as having 7 layers, in other embodiments, the soft sealing case 1945 can comprise three layers: a layer of foil 2020 sandwiched between two insulating layers 2010. In any event, it is understood that an insulating layer 2010 is on a battery portion side of the soft sealing case 1945 (i.e. inside) such that electrical properties of the soft sealing case 1945 do not interfere with the battery portion 1909.
In some embodiments, the soft sealing case 1945 comprises a flexible pouch, with at least one side deformed to provide space for the battery portion 1909. The flexible pouch can comprise two sheets of suitable material, which are heat sealed together with the battery portion 1909 therein. Furthermore, it is understood that tabs of the battery portion 1909, similar to tabs 352 and 362 depicted in FIG. 3B, can extend through the soft sealing case 1945 such that electrical connection can be made with the battery portion 1909.
Attention is now directed to FIG. 21, which depicts a schematic cross-section of a battery 2108, similar to battery 1908 of FIG. 19, with like elements having like numbers, however preceded by “21” rather than “19”. For example, the battery 2108 comprises a soft sealing case 2145 similar to soft sealing case 1945, however the soft sealing case 2145 comprises a high magnetic permeability material, including but not limited to Mu Metal. For example, in some embodiments, the soft sealing case 2145 can be coated with the high magnetic permeability material using any suitable coating technique, including but not limited to spray coating methods, heat adhesion coating methods, chemical deposition methods, and the like. In some of the embodiments, the individual sheets of the soft sealing case 2145 can be coated with the high magnetic permeability material prior to being heat sealed together and/or deformed.
In other embodiments, the high magnetic permeability material can be incorporated into the soft sealing case 2145 by replacing the aluminum foil (and the like) with foil comprising the high magnetic permeability material. For example, FIG. 22 depicts a schematic cross-section of a non-limiting embodiment of the soft sealing case 2145 comprising a flexible layer 2220 of a high magnetic permeability material, including but not limited to Mu Metal foil, sandwiched between two flexible layers 2210 of an insulating material, including but not limited to a polymer material. In these embodiments, the thickness of the layer 2220 can be optimized to balance strength, magnetic shield and flexibility. Furthermore, it is understood that the soft sealing case 2145 can comprise any suitable number of layers of foil 2220 and any suitable number of layers 2210 of insulating material, in any suitable order, though generally the battery portion side of the soft sealing case 2145 comprises a layer 2210 of the insulating material, as described above.
In some embodiments, as depicted in schematic cross-section in FIG. 23, the soft sealing case 2145 can comprise at least one layer 2320 of flexible metal foil, including but not limited to aluminum foil, in addition to at least one layer 2220 of high magnetic permeability material and at least one layer 2210 of insulating material. Incorporation of the at least one layer 2320 of metal foil can improve certain physical properties of the soft dealing case 2145, such as strength.
Persons skilled in the art will appreciate that there are yet more alternative implementations and modifications possible for implementing the embodiments, and that the above implementations and examples are only illustrations of one or more embodiments. The scope, therefore, is only to be limited by the claims appended hereto.

## Claims

1. A power pack comprising:
a battery portion producing magnetic flux when in operation; and,
a sealing portion configured to seal the battery portion therein such that the battery portion is protected from moisture, the sealing portion comprising a magnetic shield portion configured to prevent the magnetic flux from leaking through a receiver side of the power pack.

2. The power pack of claim 1, wherein the magnetic shield portion is internal to the sealing portion.

3. The power pack of claim 1, wherein the magnetic shield portion comprises a coating on a surface of the sealing portion.

4. The power pack of claim 1, wherein the sealing portion comprises a rigid sealing can, providing structural stability to the battery.

5. The power pack of claim 4, wherein the magnetic shield portion is structurally incorporated into the rigid sealing can.

6. The power pack of claim 5, wherein the magnetic shield portion comprises a high magnetic permeability material.

7. The power pack of claim 4, wherein the rigid sealing can comprises a can portion configured to contain the battery portion therein, and a plate portion, attached to the can portion, configured to seal the battery portion in the sealing can.

8. The power pack of claim 1, wherein the sealing portion comprises a soft sealing case.

9. The power pack of claim 8, wherein the soft sealing case comprises at least one flexible layer of insulating material and at least one flexible layer of high magnetic permeability material.

10. The power pack of claim 9, wherein the magnetic shield portion comprises the at least one flexible layer of high magnetic permeability material.

11. The power pack of claim 9, wherein the soft sealing case further comprises a layer of the flexible insulating material on a battery portion side of the soft sealing case.

12. The power pack of claim 9, wherein the soft sealing case further comprises at least one flexible layer of metal foil.

13. The power pack of claim 1, wherein the magnetic shield portion is further configured to substantially contain the magnetic flux within the sealing portion.

14. The power pack of claim 1, wherein the magnetic shield portion is further configured to route the magnetic flux there through.

15. The power pack of claim 1, wherein the magnetic shield portion is further configured to prevent the magnetic flux from leaking through a receiver side portion of the power pack.

16. The power pack of claim 1, wherein the magnetic shield portion comprises a high magnetic permeability material.

17. The power pack of claim 1, wherein the magnetic shield portion comprises Mu Metal.

18. The power pack of claim 1, further comprising connectors to the battery portion through the sealing portion.