DESCRIPTION [Title of Invention] BATTERY I>ACK AND METHOD OF INSPECTING STORAGE STATE OF SECONDARY BATTERY IN BATTERY RACK TECHNICAL FIELD [0001] The present invention relates to a battery pack, and to a method of i i inspecting a storage state of a secondary battery in a battery pack. BACKGROUND ART [0002] A battery pack has been heretofore used for various portable apparatuses such as a mobile phone, a digital still camera, a portable game machine, a notebook personal computer, and an electric power tool. Currently, applications thereof are not limited thereto, and the battery pack has been increasingly used in the fields necessitating a higher output and a higher capacity such as an electric assist bicycle, an electric vehicle, and further, a home electric storage device. [0003] A lithium ion secondary battery is one of the most-mainly-used secondary batteries as secondary batteries buih into a battery pack. The lithium ion secondary battery has muhiple characteristics as follows. That is, the lithium ion secondary battery is repeatedly usable by charging, has a high voltage output, has high energy density, has little self-discharge, and has a long life. Therefore, the lithium ion secondary battery is used in an extremely-broad range. However, since the lithium ion secondary battery contains a combustible material, adequate care is necessary in I handling thereof Further, for addressing needs of apparatuses such as a higher output 1 i j SP262502 f and a higher capacity, the number of cases in which secondary batteries (single cells) are multiply-series-connected or multiply-parallel-connected, and are used in a state of a battery pack (assembled battery) is increased, and therefore, more proper handling thereof is desired. Furthermore, in order to determine whether or not a battery pack mounted on an apparatus is safely usable for the apparatus, many battery certification systems for acting certification between an apparatus and a battery pack have been introduced. Accordingly, usage of an inappropriate battery pack is allowed to be restricted by various certification methods including whether or not an appropriate I i battery pack is used and whether or not an appropriate protection circuit is included. | I [0004] There is concern that what we call an altered battery pack is manufactured i I and distributed by disassembling a spent battery pack, to take out a secondary battery, '• and to build the secondary battery into another battery pack. In such an altered battery pack, undesired over-charge, undesired over-discharge, and/or the like may occur by inappropriately combining secondary batteries, and therefore, a safety issue easily occurs. Therefore, it is strongly desired to appropriately suppress manufacture and distribution of the altered battery pack, for example, by disqualifying such an altered battery pack or substantially disabling a function of the altered battery pack. [0005] A battery pack with an approval function is known from, for example, Japanese Unexamined Patent Application Publication No. 2009-151953. A battery pack (1) disclosed in the foregoing unexamined patent publication is a battery pack having a battery (14) capable of being charged and discharged, and being built into an electronic apparatus (2). The battery pack is characterized in that the battery pack has a certification means (6) that communicates with the electronic apparatus (2) and that implements certification according to a cryptographic algorithm using a code key (8) shared with the electronic apparatus (2). The battery pack is further characterized in 2 i SP262502 « that in the case where a remaining battery level detection circuit (10) capable of detecting a remaining level of the battery (14) is included in the battery pack (1), the certification means (6) is mounted in the remaining battery level detection circuit (10) as software or hardware. [Citation List] [Patent Literature] [0006] [PLT 1]: Japanese Unexamined Patent Application Publication No. 2009-151953 SUMMARY OF INVENTION [0007] However, in PLT 1, the code key (8) is included in the certification means (6). Therefore, in the case where the code key (8) is revealed in some way, it may not be possible to prevent taking out a battery from a battery pack and manufacturing an altered battery pack. In other words, there is an issue that, in the case where a kind of i fixed (that is, previously determined) information on a battery pack is stored in the I battery pack, if such information is read out, it may not be possible to prevent manufacture of an altered battery pack. [0008] Therefore, it is an object of the present invention to provide a battery pack capable of preventing manufacture of an altered battery pack by a simple configuration and a simple structure, and to provide a method of inspecting a storage state of a secondary battery in such a battery pack. [0009] A battery pack of the present invention to achieve the foregoing object includes: a plurality of secondary batteries; and an inspection circuit. Each of the secondary batteries is previously given an identification mark. When the plurality of 3 i I SP262502 secondary batteries are classified into a first secondary battery group and a second secondary battery group, the first secondary battery group being configured of secondary batteries selected from the plurality of secondary batteries, and the second secondary battery group being configured of remaining secondary batteries not belonging to the first secondary battery group, the inspection circuit creates a first data string of the secondary batteries configuring the second secondary battery group, based i on a predetermined arithmetic rule, fi-om the identification marks of the secondary 1 batteries configuring the first secondary battery group, obtains a second data string by I i examining the identification marks of the secondary batteries configuring the second | secondary battery group, subsequently compares the first data string with the second data string, and stops a function of the battery pack when the first data string and the second data string do not match. [0010] A method of inspecting a storage state of a secondary battery according to a first embodiment of the present invention to achieve the foregoing object (hereinafter abbreviated to "inspecting method according to the first example of the present invention" in some cases) is a method of inspecting a storage state of a secondary battery in a battery pack, the battery pack with a plurality of secondary batteries and an inspection circuit, the method including, when the plurality of secondary batteries are classified into a first secondary battery group and a second secondary battery group, the first secondary battery group being configured of secondary batteries selected from the plurality of secondary batteries, the second secondary battery group being configured of remaining secondary batteries not belonging to the first secondary battery group, and the secondary batteries each being given an identification mark previously, allowing the inspection circuit to create a first data string of the secondary batteries configuring the second secondary battery group, based on a predetermined arithmetic rule, from the 4 SP262502 f identification marks of the secondary batteries configuring the first secondary battery group, to obtain a second data string by examining the identification marks of the secondary batteries configuring the second secondary battery group, subsequently to compare the first data string with the second data string, and to stop a function of the battery pack when the first data string and the second data string do not match. [0011] A method of inspecting a storage state of a secondary battery according to a second embodiment of the present invention to achieve the foregoing object (hereinafter abbreviated to "inspecting method according to the second embodiment of the present invention" in some cases) is a method of inspecting a storage state of a secondary battery in a battery pack, the battery pack with a plurality of secondary batteries and an inspection circuit, the method including, when the plurality of secondary batteries are classified into a first secondary battery group and a second secondary battery group, the first secondary battery group being configured of secondary batteries selected from the plurality of secondary batteries, and the second secondary battery group being configured of remaining secondary batteries not belonging to the first secondary battery group, in charging the secondary batteries, allowing the inspection circuit to form a charge current change in the secondary batteries configuring the first secondary battery group into data to create a first data string of the secondary batteries configuring the second secondary battery group based on a predetermined arithmetic rule, to form a charge current change in the secondary batteries configuring the second secondary battery group into data to obtain a second data string, subsequently to compare the first data string with the second data string, and to stop a fiinction of the battery pack when the first data string and the second data string do not match. [0012] In the battery pack of the present invention or the inspecting method according to the first embodiment of the present invention, the first data string of the I i 5 SP262502 secondary batteries configuring the second secondary battery group is created, based on the predetermined arithmetic rule, from the identification marks (identification mark information or indexes) of the secondary batteries configuring the first secondary battery group, and the second data string is obtained by examining the identification marks of the secondary batteries configuring the second secondary battery group. Further, in the inspecting method according to the second embodiment of the present invention, the charge current change in the secondary batteries configuring the first secondary battery group is formed into data to create the first data string of the secondary batteries configuring the second secondary battery group based on the predetermined arithmetic rule, and the charge current change in the secondary batteries configuring the second secondary battery group is formed into data to create the second data string. That is, it is not necessary to store the first data string in the inspection circuit and to store an arrangement state of the secondary batteries in the inspection circuit, and it is enough that only a predetermined operation rule is stored in the inspection circuit. In other words, it is not necessary to store kind of fixed (that is, previously-determined) information of the battery pack in the battery pack. Therefore, it is possible to easily, appropriately, and highly safely detect alteration of a battery pack that is an attempt to improperly replace a secondary battery, and to securely prevent manufacture of an altered battery pack. Further, in the case where a secondary battery, a printed board including an inspection circuit, and/or the like is replaced by a manufacturer and/or the like, it is not necessary to rewrite various information. BRIEF DESCRIPTION OF THE DRAWINGS [0013] [FIG 1] Parts (A) to (D) of FIG 1 are diagrams illustrating an arrangement and the like of secondary batteries configuring a first secondary battery 6 I SP262502 f group and a second secondary battery group for explaining a mettiod of inspecting a storage state of a secondary battery in a battery pack according to Example 1. [FIG 2] Parts (A) to (E) of FIG 2 are diagrams for explaining change of a first data string and a second data string in the case where a secondary battery is taken out from a storage section and a/the secondary battery is stored in the storage section again in the method of inspecting a storage state of a secondary battery in the battery pack according to Example 1. [FIG 3] Parts (A) to (J) of FIG 3 are diagrams for explaining change of the first data string and the second data string in the case where a secondary battery is taken out from a storage section and a/the secondary battery is stored in the storage section again in a modification of the method of inspecting a storage state of a secondary battery in the battery pack according to Example 1. [FIG 4] Parts (A) to (C) of FIG 4 are a schematic cross-sectional view of a housing section configuring the battery pack according to Example 1 and schematic perspective views of a cylindrical-type secondary battery. [FIG. 5] Parts (A) and (B) of FIG 5 are a schematic perspective view of a battery pack and a schematic view in a state that a cover of the battery pack is removed, respectively. [FIG 6] Parts (A) to (F) of FIG 6 are diagrams schematically illustrating arrangement states of a secondary battery in the battery pack according to Example 1 and states of contact between detection sections and a conductive member. [FIG 7] Parts (A) and (B) of FIG 7 are a conceptual diagram of an inspection circuit and the like in the battery pack according to Example 1 and a diagram illustrating an output of an inspection signal and the like. [FIG. 8] Parts (A) and (B) of FIG 8 are schematic and partial cross-sectional 7 SP262502 t views of a main body section, a closing member, and the like. [FIG. 9] Parts (A) to (D) of FIG 9 are schematic perspective views of a rectangular cylindrical secondary battery. MODES FOR CARRYING OUT THE INVENTION [0014] The present invention will be hereinafter described based on examples with reference to the drawings. However, the present invention is not limited to the examples, and various numerical values and various materials in the examples are exemplifications. It is to be noted that the description will be given in the following order. 1. General Description of Battery Pack of Present Invention and Inspecting methods according to First Embodiment and Second Embodiment of Present Invention 2. Example 1 (Battery Pack of Present Invention and Inspecting method according to | First Embodiment of Present Invention) 3. Example 2 (Battery Pack of Present Invention and Inspecting method according to Second Embodiment of Present Invention) and Others [0015] [General Description of Battery Pack of Present Invention and Inspecting methods according to First Embodiment and Second Embodiment of Present Invention] In the battery pack of the present invention and the battery pack in the inspecting method according to the first embodiment or the second embodiment of the present invention, when the number of the plurality of secondary batteries is No and the number of the secondary batteries configuring the first secondary battery group is Ni, a configuration may be employed in which 2