Battery Pack System

Abstract

An improved battery pack and system including such battery pack is disclosed. The battery pack includes a power control module positioned to allow for increased battery power or reduced battery pack size.

Description

TECHNICAL FIELD

The described embodiments relate generally to a battery pack system. More particularly, the present embodiments relate to improvements in packaging lithium-ion battery packs used in electronic devices to reduce the battery pack size and to improve system performance.

BACKGROUND

Recent advances in portable computing have utilized lithium-ion batteries to provide power to laptops computers, portable media players, personal digital assistants (PDAs), cell phones, tablets and other electronic equipment. Lithium-ion batteries are favored because, pound for pound, they are some of the most energetic rechargeable batteries available. They have a number of important advantages over competing technologies. They are generally much lighter than other types of rechargeable batteries of the same size because the electrodes of a lithium-ion battery are made of lightweight lithium and carbon.

In addition to consumer electronics, lithium-ion batteries are also popular for use in military, electric vehicle and aerospace applications. Lithium-ion batteries may be used in place of lead acid batteries in golf carts and utility vehicles. Lithium-ion batteries provide similar voltage levels as lead acid batteries so no modification of the vehicle's drive system is needed. The batteries could also be used for electric tools, medical equipment and other uses.

Lithium is a highly reactive element, meaning that a lot of energy can be stored in its atomic bonds. This translates into a very high energy density for lithium-ion batteries. For example, a typical lithium-ion battery can store 150 watt-hours of electricity in 1 kilogram of battery. A NiMH (nickel-metal hydride) battery pack can store perhaps 100 watt-hours per kilogram, although 60 to 70 watt-hours might be more typical. A lead-acid battery can store only 25 watt-hours per kilogram. Using lead-acid technology, it takes 6 kilograms to store the same amount of energy that a 1 kilogram lithium-ion battery can handle. For lightweight electronic devices, this is a significant advantage.

In addition to being lightweight, a lithium-ion battery pack may lose only about 5 percent of its charge per month, compared to a 20 percent loss per month for NiMH batteries. Lithium-ion battery packs have no memory effect, which means that a user does not have to completely discharge them before recharging, as with some other battery types. Lithium-ion batteries can also be recharged hundreds of times while other battery types may have more limited useful lives.

While lithium-ion batteries have many positive advantages, there are some disadvantages also. For example, lithium-ion battery packs require that a protection circuit be included to maintain voltage and current within safe limits. It is possible that failure of the battery pack due to overheating could cause harm to the accompanying electronic device, possibly even melting the device housing in certain instances. In order to avoid such situations, a protection circuit is generally included in a lithium-ion battery pack. Built into each pack, the protection circuit limits the peak voltage of each cell during charge and prevents the cell voltage from dropping too low on discharge. In addition, the cell temperature is monitored to prevent temperature extremes. With these precautions in place, the possibility of metallic lithium plating occurring due to overcharge may be greatly reduced.

However, while the protection circuits are included for safety reasons they tend to make the battery packs relatively more expensive and the inclusion of protection circuits make the battery pack larger than it would otherwise be. This increase in size may ameliorate some of the advantages discussed above as electronic devices become increasingly smaller and more compact.

A jelly roll design is the design used in many rechargeable batteries, and often for those batteries used in portable electronic devices. In this design, an insulating sheet is laid down, then a thin layer of an anode material is laid down, a separator layer is applied, and a cathode material is layered on top. This sandwich is then rolled up and inserted into a hollow casing. The battery, once wrapped, may be sealed in a flexible container. The container may have a tail or seam where the flexible material seals to itself in order to encompass the battery. Electrodes may extend through the tail in order to provide an electrical connection between the battery and internal components. The electrodes may exit the flexible container, bend, and be electrically connected to various components as desired.

Therefore, it would be desirable to have a battery pack for an electronic device which is more compact, while still including the safety features associated with a protection circuit built into the battery pack

SUMMARY

A battery pack includes a power control module to protect the battery from being overcharged or improperly discharged. The power control module is located on the battery pack in a location that permits the space for the battery portion itself to be utilized to maximum efficiency. By locating the power control module on the side of the battery pack housing opposite to the battery portion, improved overall power performance of the system may be achieved. In some embodiments, increased battery performance and power may be achieved without increasing the overall size of the battery pack. In another embodiment the overall battery pack size may be reduced while maintaining the same power performance as with the conventionally sized battery pack.

A system including an electronic device which utilizes various embodiments of the battery back is disclosed. The electronic device may be a laptop computer, tablet, smartphone or the like and the power needs of the device may be met in a more efficient manner utilizing disclosed embodiments. The battery pack may be made smaller thus reducing the amount of space which must be allocated in the electronic device for the battery pack. In another embodiment, increased battery size may be achieved while maintain the size of the allocated space for the battery pack. By reducing required space or increasing the amount of power supplied to the electronic device from the battery pack for a given size, improved efficiency and performance as well as increased convenience to a user of the electronic device may be achieved with disclosed embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:

FIG. 1 shows a perspective view of an electronic device;

FIG. 2 shows the underside of an electronic device;

FIG. 3 shows a side view of a conventional battery pack;

FIG. 4 shows a side cutaway view of an electronic device including a conventional battery pack;

FIG. 5 shows a side view of a battery pack in accordance with one embodiment;

FIG. 6 shows a side cutaway view of an electronic device including a battery pack in accordance with one embodiment;

FIG. 7 shows a side view of a battery pack in accordance with another embodiment;

FIG. 8 shows a side cutaway view of an electronic device including a battery pack in accordance with another embodiment;

FIG. 9 shows a perspective view of a conventional battery pack housing;

FIG. 10 shows a perspective view of a battery pack housing in accordance with one embodiment;

FIG. 11 shows a perspective view of a battery pack housing in accordance with another embodiment; and

FIG. 12 shows a flow chart illustrating a method for making a battery pack.

DETAILED DESCRIPTION

Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims.

The following disclosure relates to a battery pack which may be used in conjunction with an electronic device such as a laptop computer, portable media player, personal digital assistant (PDA), cell phone, tablet or other electronic equipment. In a particular embodiment, the battery pack includes a lithium-ion battery and a power control module or safety circuit which is included to maintain voltage and current within safe limits. Built into each pack, the protection circuit limits the peak voltage of each cell during charge and prevents the cell voltage from dropping too low on discharge. In addition, the cell temperature may be monitored to prevent temperature extremes which could damage the battery or the electronic device.

These and other embodiments are discussed below with reference to FIGS. 1-7. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these Figures is for explanatory purposes only and should not be construed as limiting.

FIG. 1 illustrates a laptop computer 11 which may include a screen 12 and a keyboard 13 as well as a mouse pad 14. Laptop computer 11 may also include a battery pack (not shown) which is generally located on the underside 15 of laptop computer 11. The battery pack is used to provide power to laptop computer 11 and its electronic components. As stated above, the electronic device in this embodiment could also be a portable media player, cell phone, or other device.

Referring to FIG. 2, the underside 15 of laptop computer 11 is shown which includes a battery pack 16 inserted into a compartment 17 in the underside 15 of laptop computer 11. Battery pack 16 may be electromagnetically connected to the main logic board (not shown) and other electronic circuit board or components.

Referring to FIG. 3, a side view of a conventional battery pack 16 is shown. Battery pack 16 includes battery portion 19, a power control module 23 and an electrode attachment portion 20 which attaches electrode 21 to battery portion 19. Power control module 23 is shown mounted adjacent to battery portion 19 and electrode attachment portion 20. Depending upon the size and power rating of battery portion 19, battery portion 19 has a length of B1. Power control module 23 also has a dimension of length PCM 1. This configuration results in an overall length of battery pack 16 of L1 which is B1+PCM1=L1. L1 is the approximate length of compartment 17 in electronic device 11 as shown and described in FIG. 4 below.

The power control module 23 shown in FIG. 3 is included for safety reasons as described above. That is, in certain battery types, such as lithium-ion batteries, it is important to control the charge and discharge rate of the lithium-ion battery to prevent inadvertent failure of the battery portion 19 which could damage electronic device 11 and/or its electronic circuitry 22. In addition, as discussed above, power control module 23 may monitor the temperature of battery portion 19 in order to prevent inadvertent overheating of battery portion 19 which could result in failure of battery portion 19.

Referring to FIG. 4, a cutaway side view of electronic device 11 includes a housing 18. Housing 18 includes a compartment 17 which contains battery pack 16 described above with respect to FIG. 3. Battery pack 16 includes a battery 19 which is connected through electrode connection 20 to electrode 21. Electrode 21 connects battery pack 16 to a main logic or circuit board 22. In this conventional battery pack, a power control module 23 is included in battery pack 16 and is positioned adjacent to electrode attachment portion 20, electrode 21 and battery portion 19 above the main logic board 22 and other electronic components. Battery portion 19 may be a lithium-ion battery or other battery type. Compartment 17 in housing 18 is defined by a width (measured from above and not shown), depth (D1) and length (L1) which is sized to allow insertion and removal of battery pack 16 as will be discussed in more detail below. That is, a cover portion 24 in underside 15 of electronic device 11 may be opened to allow access to battery pack 16. Battery pack 16 may be removed by a user and replaced or recharged as needed.

Referring to FIG. 5, a side view of an embodiment of a battery pack 24 is shown which includes power control module 23 mounted below electrode 21. By locating power control module 23 below electrode 21, battery portion 19 may be made larger with a length of B2 as shown in FIG. 5 while still maintain an overall length for battery pack 24 of L1. By making battery portion 19 larger, an increase in power may be achieved. That is more space may be provided for the three primary functional components of a lithium-ion battery: the positive and negative electrodes; and the electrolyte. The overall length L1 of battery pack 24 remains the same as with battery pack 16 described above such that battery pack 24 may fit into compartment 17 in electronic device 11 as described above but the increased power increases the usefulness of electronic device 11 by enabling more capabilities.

Referring to FIG. 6, the battery pack 16 of FIG. 5 is shown in a cutaway view of compartment 17 of electronic device 11. The overall length of battery pack 16 is L1 as was the case with the conventional battery pack 16 shown in FIG. 4. Power control module 23 is shown mounted below electrode attachment portion 21 as described above with respect to FIG. 5. Thus, in this embodiment, battery portion 19 may be made larger resulting in more power to electronic device 11 and/or longer battery life between recharging of battery portion 19. That is, battery portion 19 has a length B2 as described above with respect to FIG. 5. Thus, while the overall length L1 of battery pack 24 is the same as that of conventional battery pack 16 in FIG. 4, the larger battery portion length B2 results in additional amount of battery power which may be delivered to electronic device 11 which can result in improved performance and enabling additional capabilities.

Referring to FIG. 7, another embodiment of a battery pack is shown. In this embodiment, a battery pack 25 includes a battery portion 19 which includes a length B1 as was shown in the embodiment described in FIGS. 3 and. 4. However, because power control module 23 is located on the underside of electrode attachment portion 21, the overall length of battery pack 25 is L2 which is less than length L1 of the battery packs described in FIGS. 3 and 4. Thus battery pack 25 has the same battery power level as battery pack 16 shown in FIGS. 3 and 4 because it has the same sized battery portion 19. However, battery pack 25 has a length L2 that is less than length L1 of battery pack 16 and thus may allow a reduction in the size of electronic device 11. As the size of electronic devices continues to decrease, reducing the size of a battery pack while maintaining the same power capabilities may be significant.

Referring to FIG. 8, the battery pack 25 of FIG. 7 is shown in a compartment 26 of electronic device 11. The overall length of battery pack 25 is L2 as shown in FIG. 7 which is less than the length L1 of the battery pack shown in FIG. 3. Power control module 23 is shown mounted below electrode 21 as described above with respect to FIG. 7. In this embodiment, battery portion 19 has a length B1 as described above in FIG. 7 and FIG. 3. This means that battery pack 25 may provide the same power performance as battery pack 19 shown in FIG. 3. However, because the length L2 of battery pack 25 is less than the length L1 of battery pack 16, the length of compartment 26 may be smaller than the length of compartment 17 in FIGS. 4 and 6. Thus, the same battery power level can be provided to electronic device 11 as with the battery pack 16 of FIGS. 3 and 4 but, because the length L2 of compartment 26 in FIG. 7 is less than length L1 of compartment 17 in FIG. 4, the size of electronic device may either be reduced or, if the size of electronic device is maintained, additional components may be added resulting in increased performance or convenience to a user.

Referring to FIG. 9, a perspective view of a housing for conventional battery pack 16 is shown. Housing 27 is a tray like structure that contains the battery portion (not shown) adjacent upper surface 28. The length B1 of tray in housing 27 is sufficient to contain the battery portion of a size having a particular power capability. In this conventional battery pack, housing 27 has power control module 23 located adjacent to electrode portion 21 and upper surface 28. A main logic board or other circuitry may connect to electrode portion 21 at flexible attachment point 31 on lower surface 29. Battery pack 16 has an overall length of L1 as shown.

Referring to FIG. 10, a perspective view of an embodiment is shown including housing 27 as described in FIG. 9 above. That is, a power source, which may be a battery portion is contained on the upper surface 28 of housing 27 and an electrode 21 is connected to the power source. In this embodiment, power control module 23 is moved adjacent to electrode portion 21 and lower surface 29. Flexible attachment point 31 may be extended as necessary or desirable to provide sufficient connection to main logic board or other circuitry (not shown). By moving power control module 23 to this location adjacent lower surface 29, the amount of space to contain battery portion (not shown) is increased from that shown in FIG. 9. That is, the length B2 of the space to contain battery portion 19 is increased from length B1 shown in FIG. 9. Thus, a larger battery portion 19 having higher power capability may be included in housing 27 without increasing the overall length L1 of the battery pack which remains the same as L1 in FIG. 9.

Referring to FIG. 11, an alternate embodiment of a battery pack is shown. In this embodiment, power control module 23 is moved adjacent to flexible attachment point 31 on electrode portion 21 as is described above with respect to FIG. 10. As with the embodiment shown in FIG. 10 attachment point 31 may be extended as necessary or desirable to provide sufficient connection to main logic board or other circuitry (not shown). In the embodiment shown in FIG. 11, however, housing 27 has been shortened such that the overall length L2 of the battery pack is less than length L1 of the battery pack described in FIGS. 9 and 10. The length B1 of the tray portion in housing 27 is maintained as in FIG. 9 such that the same sized battery portion as is used in FIG. 9 may be included in this embodiment. Thus a more compact battery pack having a shorter overall length L2 may be used to provide power to electronic device 11 without reducing the amount of such provided power. With this embodiment, either the overall size of electronic device could be reduced, or additional components could be added to electronic device 11 without increasing the overall size of electronic device 11. That is, the size of battery compartment 17 in FIG. 2 could be reduced without sacrificing power capabilities or device performance. By adding additional components to the freed space, improved performance and/or increased convenience to a user of electronic device 11 may be accomplished. Similarly, reducing the size of electronic device 11 would also result in increased convenience to a user of the device.

As discussed above, (for example with respect to FIG. 4) both conventional battery packs and embodiments of battery packs disclosed herein may be inserted into and removed from electronic devices such as laptop computers. The battery packs may then be replaced, recharged or repaired as needed. The embodiments disclosed herein do not add any complexity to this removal process but do allow for increased efficiency or reduction in size of the device as discussed above. The absolute amount of reduction in size from, for example, L1 to L2, is provided for illustrative purposes only. It is the relocation of power control module 23 to a bottom surface of the battery pack that permits the increased efficiency or reduced size. The electrodes 21 on the battery packs may interface with electrical connections such as the main logic boards and other electronic circuitry. While lithium-ion batteries have been discussed as the power source in battery portions 19 and 25, it can be appreciated that embodiments described herein could be employed with battery portions employing other battery chemistries which utilize power control modules to control battery pack functionality for safety and efficiency improvements.

Referring to FIG. 12, a flow chart for a method of making a battery pack is shown. In step 32, a housing having an upper and a lower surface is provided. In step 33, a power source is contained adjacent to the upper surface in the housing. An electrode is connected to the power source in step 34. A power control module is attached adjacent to the lower surface of the housing in step 35. The power source may be a lithium-ion battery and the power control module is attached adjacent the lower surface such that it is contained with a battery pack length defined by the battery portion and the attached electrode.

It can be appreciated from the above description that moving power control module 23 on a lithium-ion or other battery type, may result in improved efficiencies to battery packs and to the electronic or other devices that utilize them. By improving such efficiencies, greater performance and convenience may be provided to a user of electronic devices. However, embodiments disclosed herein could be used in other than electronic devices. For example, electric powered automobiles or other electric powered forms of transportation such as utility vehicles utilize battery packs and may benefit from implementation of the embodiments disclosed herein. In addition, electric tools, medical equipment and other uses may benefit from these embodiments.

The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not target to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Claims

1. A battery pack, comprising:

a housing including an upper surface and a lower surface;

a battery portion adjacent said upper surface;

an electrode portion connected to said battery portion, said electrode portion extending adjacent said lower surface; and

a power control module adjacent said lower surface.

2. The battery pack of claim 1 wherein said battery portion is a lithium-ion battery.

3. The battery pack of claim 1 wherein said battery portion and said electrode portion define a first length of said battery pack.

4. The battery pack of claim 3 wherein said power control module is included within said first length.

5. The battery pack of claim 3 wherein said battery portion has a battery power level.

6. The battery pack of claim 5 wherein said battery power level remains the same and the battery portion and the electrode portion define a second length which is less than the first length.

7. The battery pack of claim 3 wherein said first length is less than a third length defined by said power control module mounted adjacent said upper surface.

8. The battery pack of claim 7 wherein said battery portion and said electrode portion define said first length and said battery portion includes a battery power level more than said battery power level of said battery portion in said third length and wherein said first length and said third length are approximately equal.

9. An electronic device comprising:

a main logic board;

a battery pack electromagnetically connected to said main logic board, said battery pack including: a housing having an upper and a lower surface; a power source contained adjacent said upper surface; and a power control module adjacent to said lower surface.

10. The electronic device of claim 9 wherein said electronic device includes a laptop computer.

11. The electronic device of claim 9 wherein said electronic device includes a portable media player.

12. The battery pack of claim 9 wherein said power source is a lithium-ion battery.

13. The battery pack of claim 9 wherein said power source and an electrode portion define a first length of said battery pack.

14. The battery pack of claim 13 wherein said power control module is included within said first length.

15. The battery pack of claim 13 wherein said power source has a battery power level.

16. The battery pack of claim 15 wherein said battery power level remains the same and the power source and the electrode portion define a second length which is less than the first length.

17. The battery pack of claim 13 wherein said first length is less than a third length defined by said power control module mounted adjacent said upper surface.

18. The battery pack of claim 17 wherein said power source and said electrode portion define said first length and said power source includes a battery power level more than said battery power level of said power source in said third length and wherein said first length and said third length are approximately equal.

19. A method for making a battery pack comprising the steps of:

providing a housing having an upper and a lower surface;

containing a power source adjacent said upper surface;

connecting an electrode to said power source; and

providing a power control module adjacent to said lower surface.

20. The method of claim 19 wherein said power source includes a lithium-ion battery.