Chemistry: electrical current producing apparatus – product – and – Cell support for removable cell – Support or holder per se
Reexamination Certificate
2000-06-21
2002-09-17
Chaney, Carol (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Cell support for removable cell
Support or holder per se
C429S096000, C429S097000, C429S099000, C429S127000, C429S136000, C429S124000, C429S148000, C429S153000, C429S159000, C429S162000, C429S163000, C429S167000, C429S176000, C429S177000
Reexamination Certificate
active
06451474
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a battery pack constituted using secondary batteries which are formed accommodating electricity generating elements within a soft external case, in order to achieve reduction in size, weight and thickness that is required for battery power sources of portable information equipment such as mobile telephones or mobile computers.
The ratio represented by the batteries in the volume and weight of portable information equipment such as mobile telephones or mobile computers is considerable, and it is no exaggeration to say that batteries hold the key to reduction in size, weight and thickness of portable information equipment.
Flat-shaped lithium ion secondary batteries are employed in order to respond to such demands for reduction in size, weight and thickness of portable information equipment; however, it is anticipated that lithium polymer secondary batteries may provide secondary batteries capable of further reductions in weight and thickness. In particular those formed by accommodating electricity-generating elements in the form of a laminated sheet within an external casing are effective in realizing reductions in weight and thickness.
In secondary batteries of high energy density such as lithium-based secondary batteries, in order to prevent deterioration or damage to the battery by overcharging, over-discharging, or excessive discharge current etc., the use of a battery protective device constituted using a protection circuit or PTC etc. is indispensable. Such is accommodated in a battery pack case together with the secondary battery to constitute a battery pack.
However, swelling of the external casing occurs when the secondary battery undergoes expansion of the electrode plates due to repeated charging/discharging and/or changes over time, or when gas is generated by decomposition of the electrolyte due to causes such as being left at high temperature in a fully charged condition. When such a condition is generated in the secondary battery accommodated in the pack case, the swelling of the secondary battery is communicated to the pack case, producing changes in the external dimensions of the pack case. In the case of miniature portable equipment such as mobile telephones, the battery pack faces the constituent elements of the equipment with only a slight intervening gap, wherefore changes in the external dimensions of the pack case affect the equipment. In particular, in the case of a secondary battery wherein the external casing is formed by soft material such as laminated sheet, expansion of the electrode plates or generation of gas immediately produces swelling of the external casing, and this produces swelling of the pack case, changing its external dimensions.
Also, in the case of secondary batteries of a construction in which a group of laminated electrode plates constituted by laminating a plurality of positive and negative electrode plates is accommodated in a soft external casing made of for example laminated sheets, the restraining force whereby the external casing holds the positive and negative electrode plates in their prescribed positions is weak, so positional displacement of the electrode plates can easily occur when subjected to shock or vibration, giving rise to the problem of damage such as internal short-circuits or disconnections being easily produced. Also, even in the case of a secondary battery of a construction in which electrode plates in which positive and negative electrode plates are coiled are accommodated in a soft external casing, damage occurs due to disconnections etc. produced by movement of the electrode plates. Also, since the laminated sheets are formed by disposing a resin layer on both sides of a metallic layer, if a secondary battery is displaced within the pack case by vibration or shock, the resin layer is destroyed by contact with metallic members arranged within the pack case, giving rise to short-circuiting between the metallic members and metallic layer.
An object of the present invention is to provide a battery pack in which reduction in size, weight and thickness are achieved by solving the problems in a battery pack employing a secondary battery in which a soft material is used for the external casing.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, a battery pack wherein a secondary battery formed in flat plate shape by accommodating electricity generating elements within an external casing formed of soft material is accommodated in a pack case is characterized in that a face on one side of said pack case, facing a flat plate face of said secondary battery, is formed as a resiliently deformable face that deforms resiliently corresponding to changes in thickness of the secondary battery, while the face on the other side is formed as a rigid face consisting of a rigid element.
With such a construction, although it might be feared that if the secondary battery constituted by accommodating electricity generating elements within a soft external casing such as a laminated sheet suffered expansion of the electrode plates constituting the electricity-generating element, such expansion would immediately be communicated to the external casing, producing swelling of the pack case with adverse effect on the equipment thanks to the formation of one face of the pack case opposite the battery by a resiliently deformable face, the increase in thickness of the resiliently deformable face of the battery pack takes place uniformly without swelling in specific locations, so abnormal deformation is not produced in the external shape of the battery pack, and there is thus no possibility of adverse effect on the equipment due to swelling of the battery pack. Even in the case where the aforesaid secondary battery is constituted by electricity generating elements using electrode plates of a coiled construction in which the positive and negative electrode plates are coiled, when this is formed into flat plate shape, a condition is produced in which the electrode plates are laminated in the thickness direction, so that this is the same as the case of the laminated construction in which a plurality of positive and negative electrode plates are laminated; thus swelling of the electrode plates results in a uniform increase in the thickness of the secondary battery. Thus, whether the electrode plates are of laminated construction or of coiled construction, the benefit of the resiliently deformable face is obtained.
According to a second aspect of the present invention, a battery pack wherein a secondary battery formed in flat plate shape by accommodating electricity generating elements within an external casing formed of soft material is accommodated in a pack case is characterized in that both faces of said pack case opposite flat plate faces of said secondary battery are formed as resiliently deformable faces that deform resiliently corresponding to changes of thickness of the secondary battery, and their peripheral portion is supported by a rigid element surrounding the side faces of the secondary battery.
With the above construction, in the event of swelling of the electrode plates constituting the electricity-generating element, since the thickness of the battery pack as a whole increases in uniform fashion due to the resilient deformation of the resiliently deformable faces formed on both faces of the pack case, abnormal deformation of the external shape of the battery pack cannot occur. Even when the aforesaid secondary battery is constituted by electricity generating elements employing electrode plates of coiled structure in which positive and negative electrode plates are coiled, when this is formed in flat plate shape, a condition in which the electrode plates are laminated in the thickness direction is produced, so that, just as in the case of the laminated construction in which a plurality of positive and negative electrode plates are laminated, swelling of the electrode plates results in uniform increase in thickness of the secondary battery. Conseq
Fujiwara Junji
Hirabayashi Tetsuo
Kaiwa Ryoichi
Kajiwara Shigeru
Konishi Shoji
Chaney Carol
Jordan and Hamburg LLP
Martin Angela J.
Matsushita Electric - Industrial Co., Ltd.
LandOfFree
Resiliently deformable battery pack does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Resiliently deformable battery pack, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Resiliently deformable battery pack will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2890751