JP2012174458A - Secondary battery and battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery that can detect a rise of temperature even when the temperature of the secondary battery has risen to an abnormal temperature causing battery performance to locally decline, and a battery pack.SOLUTION: A secondary battery 1 includes a temperature detection layer 5 that irreversibly changes in color over an entire outside surface of a battery body 4 except for electrode terminals 2 and 3. The temperature detection layer 5 is made of a temperature indication material constituted by thermo paint, thermo seal or the like and changes in color when reaching an abnormal temperature causing battery performance to decline.

Description

  The present invention relates to a secondary battery capable of easily discriminating a heat history during use, and an assembled battery in which a plurality of secondary batteries are combined.

  Secondary batteries such as lithium ion batteries and nickel metal hydride batteries can be used repeatedly by charging a discharged battery, and are widely used as power sources for mobile devices such as notebook computers and video cameras. ing. In recent years, large secondary batteries mounted on electric vehicles, hybrid cars, and the like have also appeared. In order to take out the voltage and power required for the device, a plurality of such secondary batteries are often used in combination as a combined battery in series or in parallel.

  By the way, the secondary battery is charged / discharged within a range of a predetermined voltage specific to the battery. While charging / discharging is repeated, internal factors such as trouble of the battery itself, troubles of the charge / discharge control circuit, etc. Due to external factors, the temperature of the battery may rise to a temperature that causes a decrease in performance (abnormal temperature). Once the secondary battery has risen to an abnormal temperature, it is difficult to restore the battery performance to the original state even if the battery temperature subsequently drops to a temperature at which there is no problem. Therefore, an abnormal battery whose performance has deteriorated needs to be replaced with a normal secondary battery.

  As a technique for increasing the temperature to such an abnormal temperature and making it possible to distinguish the battery, there is a technique for leaving the battery itself as a thermal history that the battery has reached an abnormal temperature. For example, Patent Document 1 discloses a configuration in which a 3 mm square thermolabel (detector) that is irreversibly discolored by heating is provided at a position where a dry battery or a storage battery (secondary battery) is visible from the outside of the battery. Yes. Further, the cited document 2 discloses a configuration in which an irreversible thermo tape that changes color at a certain temperature or more is disposed in a part of a rechargeable battery in which a plurality of single cells are connected in series.

  According to the above technology, when the battery reaches an abnormal temperature, the thermolabel and the thermotape change color and the discoloration is retained even after returning to the normal temperature. It is possible to determine whether the battery is a correct one.

JP 63-66865 A (published March 25, 1988) Japanese Utility Model Publication No. 60-112074 (released July 29, 1985)

  However, the conventional technology as described above has a problem that a battery in which a local temperature rise such that only a part of the battery rises to an abnormal temperature cannot be determined as an abnormal battery.

  In other words, in the conventional technology as described above, a thermo label or a thermo tape (hereinafter collectively referred to as a thermo label) is arranged only on a part of the outer surface of the battery. When the temperature rises to an abnormal temperature that changes color, it can be determined that the battery is abnormal. However, when only a part of the battery rises to an abnormal temperature, the thermo label does not change color except when the rising part is the position where the thermo label is placed, and thus an abnormality cannot be detected.

  As described above, in recent years, large-sized secondary batteries are mounted on electric vehicles, hybrid cars, and the like, and the size of secondary batteries is increasing. In such a large-sized secondary battery, it is possible that the temperature of only a part of the battery, not the entire battery, rises locally.

  And even if the temperature rises locally, a secondary battery with such an abnormality not only promotes performance degradation, but if it continues to be used as it is, the entire battery will rise to an abnormal temperature. There is a danger of causing serious trouble to the charge / discharge circuit of the secondary battery. In addition, in the case of an assembled battery, an abnormal battery is the starting point, which not only promotes a decrease in the performance of the entire assembled battery, but also causes a thermal runaway and damages other normal secondary batteries that make up the assembled battery. There is also a danger of spreading. Therefore, even if the temperature rises locally, it is necessary to determine that the battery is abnormal and to avoid serious troubles.

  The same applies to not only large secondary batteries, but also small secondary batteries mounted on mobile devices such as laptop computers. It is necessary to determine that the battery is a battery and to avoid serious troubles.

  The present invention has been made in view of the above problems, and provides a secondary battery and an assembled battery having a configuration capable of detecting this even when the temperature rises to an abnormal temperature that partially promotes performance degradation rather than the entire battery. It is aimed.

  In order to solve the above-described problems, the secondary battery according to the present invention is provided with a temperature detection layer that is irreversibly discolored by heating over at least one surface of the battery body excluding the electrode terminals. It is characterized by having.

  According to the above configuration, the entire battery has been raised to an abnormal temperature by the temperature detection layer that is irreversibly discolored by heating on the entire surface of the battery body excluding the electrode terminals. Not only an abnormality but also an abnormality in which only a part of the battery locally rises to an abnormal temperature can be detected.

  In this case, more preferably, the temperature detection layer is provided on the peripheral surface of the battery body over the entire surface, and more preferably, the temperature detection layer is provided on all surfaces of the battery body. It is the structure provided over the whole. By adopting such a configuration, even if any part of the battery body rises to an abnormal temperature, this can be reliably detected.

  However, the battery case of the secondary battery is often made of a metal having excellent thermal conductivity, and in this case, heat is easily transmitted on the outer surface of the battery. Therefore, even if the temperature detection layer is provided only on one surface of the battery body, the temperature detection layer is provided not over a part of the surface but over the entire surface. A temperature abnormality occurring on a surface different from the provided surface can be detected if the temperature rise portion is close.

  In addition, when a location that is likely to cause an abnormal temperature increase is known in advance inside or outside the battery, a temperature detection layer is provided on the entire surface by providing a temperature detection layer at least on the surface where the location enters. Even if it is not provided, a local temperature rise can be detected.

  Here, the temperature detection layer is provided over the entire surface as well as a form in which the temperature detection layer completely covers the entire surface without gaps, and the temperature detection layer is a stripe, mesh, dot, or the like. The pattern includes a form that covers the entire surface while having a gap, and a form that the temperature detection layer covers the entire surface, although there are parts that are partially cut by the temperature detection layer. Means.

  Moreover, it is not necessary to use a special inspection device or carefully observe the secondary battery, and the temperature detection layer can be detected simply by visual observation.

  In addition, since the position where the trouble has occurred can be identified from the discolored portion of the temperature detection layer, it helps to clarify the cause of the trouble. That is, in the case of a trouble inside the battery, it can be inferred in which part of the battery an abnormality has occurred. If the trouble is outside the battery, it can also be estimated in which part of the charge / discharge circuit, etc., outside the secondary battery an abnormality has occurred. The occurrence of trouble outside the battery can be detected and dealt with while the phenomenon is small, so that more serious trouble can be prevented.

  In the secondary battery according to the present invention, the battery body is further provided with a heat conducting wire made of a material having a higher thermal conductivity than the material constituting the outer surface of the battery so as to be in contact with the temperature detection layer. The heat conducting wire may be configured to transmit locally generated heat of the temperature rising portion to other regions other than the temperature rising portion.

  If the battery case has excellent thermal conductivity such as metal, it is considered possible to transfer abnormal heat generated on the surface other than the surface provided with the temperature detection layer to the surface provided with the temperature detection layer. . However, if the thermal conductivity of the battery case is low, or even if it is a metal battery case, the size of the battery is increased and the surface on which the temperature detection layer is provided is far from the temperature rise portion, the temperature detection layer is reached. It is assumed that the heat is not transmitted.

  Further, in the secondary battery attached to the fixing jig for fixing the secondary battery, when the temperature rises in the portion hidden by the fixing jig, the secondary battery is provided at a position where it can be visually observed. This heat can be detected by being transmitted to the temperature detection layer. However, if this heat is not transmitted, this abnormality cannot be detected unless the secondary battery is removed from the fixing jig. The same applies to the case where the secondary battery constitutes an assembled battery and the outer surfaces are hidden between adjacent batteries.

  On the other hand, according to the above configuration, since the heat conducting wire is provided, even if the temperature rises in the portion hidden by the fixing jig or the adjacent battery, the heat is transmitted through the heat conducting wire to improve efficiency. It is often transmitted to the temperature sensing layer. As a result, as long as the temperature detection layer is provided at a visible position, it is possible to detect an abnormality of a portion that cannot be easily viewed without removing the secondary battery.

  In this case, the heat conducting wire is preferably in the form of a ribbon having a thin thickness with respect to the line width.

  By forming the heat conducting wire into a ribbon shape that is thin with respect to the line width, when constituting an assembled battery, it is possible to prevent the batteries from coming into contact with each other or preventing them from being placed close to each other. Discoloration of the temperature detection layer due to heat can be easily recognized.

  As such a secondary battery, a combination with a lithium ion battery is suitable.

  Lithium ion batteries tend to cause side reactions when the electrolyte filled therein is heated, and the effects of heat, such as battery performance degradation, are greater than other secondary batteries. Therefore, the safety | security can be effectively improved by combining with a lithium ion battery.

  In addition, the fixing jig for fixing the secondary battery preferably has a configuration made of a transparent member. By making the fixing jig a transparent configuration, abnormality detection by the temperature detection layer can be used more effectively. .

  The present invention also includes an assembled battery in which a plurality of the secondary batteries of the present invention are connected in parallel, in series, or both.

  In particular, in this case, the fixing jig for fixing a plurality of secondary batteries is preferably made of a transparent member. By making the fixing jig transparent, abnormality detection by the temperature detection layer is more effective. Can be used.

  The secondary battery of the present invention is provided with a temperature detection layer that is irreversibly discolored by heating over at least one surface of the battery body excluding the electrode terminals. As a result, not only an abnormality that has risen up to a point, but also an abnormality in which only a part of the battery has risen locally to an abnormal temperature can be detected.

It is a perspective view which shows the external appearance of the square-shaped secondary battery provided with the temperature detection layer based on the 1st Embodiment of this invention. It is a perspective view which shows the general view of the conventional square-shaped secondary battery shown for a comparison. (A)-(f) is a perspective view which shows the modification of the said square-shaped secondary battery of this embodiment. FIG. 4 is an explanatory diagram showing a state in which the temperature of the outer surface of the battery body rises and the temperature detection layer is irreversibly discolored due to trouble inside the battery of the prismatic secondary battery of the present embodiment or trouble outside the battery. is there. 1 is a perspective view illustrating an overview of a cylindrical secondary battery according to a first embodiment of the present invention. FIG. 4 is an explanatory diagram showing a state in which the temperature of the outer surface of the battery body rises and the temperature detection layer is irreversibly discolored due to trouble inside the battery of the cylindrical secondary battery of the present embodiment or trouble outside the battery. is there. (A) is a perspective view which shows the external appearance of the square-shaped secondary battery which provided the heat conducting wire in addition to the temperature detection layer based on the 2nd Embodiment of this invention, (b) is a heat conducting wire. It is explanatory drawing which extracts and shows only. In the prismatic secondary battery according to the second embodiment, due to trouble inside the battery or trouble outside the battery, the temperature of the outer surface of the battery body rises in a portion hidden by the fixing jig, and the heat is transferred to the heat conducting wire. It is explanatory drawing which shows the state which transmitted to, and the temperature detection layer discolored irreversibly along the heat conducting wire. It is a perspective view which shows the modification of the square-shaped secondary battery of 2nd Embodiment. (A) is a perspective view which shows the general view of the cylindrical secondary battery which provided the heat conducting wire in addition to the temperature detection layer based on the 2nd Embodiment of this invention, (b) is a heat conducting wire. It is explanatory drawing which extracts and shows only. In the cylindrical secondary battery of the second embodiment, due to trouble inside the battery or trouble outside the battery, the temperature of the outer surface of the battery body rises in a portion hidden by the fixing jig, and the heat is transferred to the heat conducting wire. It is explanatory drawing which shows the state which transmitted to, and the temperature detection layer discolored irreversibly along the heat conducting wire. It is a perspective view which shows the modification of the cylindrical secondary battery of 2nd Embodiment. It is explanatory drawing which shows the example of arrangement | positioning of the battery of the assembled battery using the square-shaped secondary battery of 1st Embodiment. It is explanatory drawing which shows the connection structure between the electrode terminals in the assembled battery which has battery arrangement | positioning as shown in FIG. It is explanatory drawing which shows the connection structure between the electrode terminals in the assembled battery using the square-shaped secondary battery of 2nd Embodiment. It is explanatory drawing which shows the example of arrangement | positioning of the battery of the assembled battery using the cylindrical secondary battery of 1st Embodiment. It is explanatory drawing which shows the connection structure between the electrode terminals in the assembled battery which has a battery arrangement | positioning as shown in FIG. It is explanatory drawing which shows the connection structure between the electrode terminals in the assembled battery using the cylindrical secondary battery of 2nd Embodiment. It is explanatory drawing which shows a structure of the assembled battery of the modification which made the fixing jig transparent in the assembled battery shown in FIG. It is explanatory drawing which shows a structure of the assembled battery of the modification which made the fixing jig transparent in the assembled battery shown in FIG.

[First Embodiment]
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing an overview of a secondary battery 1 according to an embodiment of the present invention. On the other hand, FIG. 2 is a perspective view showing an overview of a conventional secondary battery 100 for comparison.

  As shown in FIGS. 1 and 2, each of the secondary batteries 1 and 100 is a square battery in which the battery body 4 forms a square shape, and the plus electrode terminal 2 and the minus electrode terminal 3 are the battery body 4. Are formed side by side on the same surface. The battery body 4 is a rectangular parallelepiped of vertical (depth) 44 × horizontal 170 × height 115 (unit mm), and electrode terminals 2 and 3 are formed on a vertical 44 × horizontal 170 surface. Note that the size is not limited to this.

  Further, the secondary batteries 1 and 100 are both lithium ion batteries, but the battery configuration may be other configurations such as a nickel metal hydride battery. However, the influence of heat, such as battery performance degradation, is more problematic in lithium ion batteries where the side-reaction is likely to occur because the electrolyte filled inside is heated. A combination is preferred.

  The difference between the secondary battery 1 of the present embodiment and the conventional secondary battery 100 is that, as shown in FIG. 1, in the secondary battery 1, the entire surface of the battery body 4 excluding the electrode terminals 2 and 3 is disposed. The temperature detection layer 5 (indicated by hatching in the figure) is provided which changes irreversibly when heated.

  The temperature detection layer 5 is a temperature indicating layer that is made of a temperature indicating material such as an irreversible thermo paint or an irreversible thermo seal and is in close contact with the outer surface of the battery body 4 of the secondary battery 1. The temperature detection layer 5 is irreversible when the temperature of the outer surface of the battery body 4 rises and reaches a predetermined temperature due to trouble inside the secondary battery 1 or trouble outside the secondary battery 1 such as a charge / discharge circuit. Discolored.

  As a specific example of the irreversible thermo paint, for example, WAX temperature ink series manufactured by Asei Kogyo Co., Ltd. can be mentioned. The series includes 40 ° C: WL-40, 45 ° C: WL-45, 50 ° C: WL-50, 55 ° C: WL-55, 60 ° C: WL-60, 65 ° C: WL-65, 70 ° C: WL-70, 75 ℃: WL-75, 80 ℃: WL-80, 85 ℃: WL-85, 90 ℃: WL-90, 95 ℃: WL-95, 100 ℃: WL-100, 105 ℃: WL -105, 110 ° C .: WL-110, 115 ° C .: WL-115, 120 ° C .: WL-120, and the temperature at which the color changes irreversibly in increments of 5 ° C. from 60 ° C. to 120 ° C. is set.

  In the secondary battery 1 of the present embodiment, WAX temperature ink WL-60 (manufactured by Asei Industrial Co., Ltd.) that changes color irreversibly at 60 ° C. is used as the temperature indicating material. The temperature detection layer 5 was obtained by applying the WAX temperature ink WL-60 to the entire outer surface of the battery body 4 excluding the electrode terminals 2 and 3 and then drying.

  The temperature indicating material that changes temperature at 60 ° C. at 60 ° C. is used in the conventional secondary battery 100 made of a lithium ion battery shown in FIG. This is because it has been experimentally confirmed that the battery performance does not recover even if the battery temperature returns to normal after that, when the battery temperature rises.

  In addition, since the temperature at which the performance of the battery is lowered varies depending on the battery configuration of the secondary battery, the members used, etc., the temperature at which the temperature detection layer 5 is irreversibly discolored is a local temperature rise, A temperature indicating material that degrades the performance of the secondary battery is selected, and a temperature indicating material that changes color at that temperature may be selected.

  The temperature detection layer 5 is most preferably provided on the entire outer surface of the battery body 4 excluding the electrode terminals 2 and 3 as shown in FIG. With such a configuration, even if any part of the battery body 4 rises to an abnormal temperature, this can be reliably detected.

  However, the configuration of FIG. 1 is the best mode, and the temperature detection layer 5 may be configured to be provided over the entire surface on at least one surface of the battery body 4 excluding the electrode terminals 2 and 3. .

  The battery case in the battery body 4 is often made of a metal having excellent thermal conductivity, and heat is easily transmitted on the outer surface of the battery. Therefore, even if the temperature detection layer 5 is provided only on one surface of the battery body 4, the temperature detection layer 5 is provided not over a part of the surface but over the entire surface. Even if a temperature abnormality occurs on a surface different from the formed surface, it can be detected if it is partially close.

  In addition, when a location where abnormal temperature rise is likely to occur inside or outside the battery is known, by providing the temperature detection layer 5 at least on the surface where the location enters, even if it is not provided on the entire surface, A local temperature rise can be detected.

  Here, the temperature detection layer 5 is provided over the entire surface as well as a form in which the temperature detection layer 5 completely covers the entire surface with no gaps, but the temperature detection layer 5 has stripes, meshes, In the pattern of dots or the like, there is a form that covers the entire surface while having a gap, or there is a part that is partially scratched by the temperature detection layer 5, but the temperature detection layer 5 covers the entire surface It is meant to include some forms.

  FIG. 3A to FIG. 3F show variations of the temperature detection layer 5. FIG. 3A shows a configuration in which the temperature detection layer 5 is provided except for the surface on which the electrode terminals 2 and 3 are formed. FIG. 3B shows a configuration in which a part of the temperature detection layer 5 formed on the entire surface of the battery body 4 is cut into a ribbon shape (reference numeral 6). FIG. 3C shows a configuration in which the temperature detection layer 5 is formed in a stripe pattern over the entire circumference of the side surface of the battery body 4. FIG. 3D shows a configuration in which the temperature detection layer 5 is provided only on the surface on which the electrode terminals 2 and 3 are formed. FIG. 3E shows a configuration in which the temperature detection layer 5 is formed in a mesh pattern only on the widest side surface of the battery body 4. FIG. 3F shows a configuration in which the temperature detection layer 5 is formed in a dot pattern over the entire circumference of the side surface of the battery body 4.

  In FIG. 4, the temperature of the outer surface of the battery body 4 rises due to a trouble inside the secondary battery 1 or a trouble outside the secondary battery 1 in the secondary battery 1 of the present embodiment. Indicates the state of irreversibly discolored. The portion indicated by reference numeral 7 is a portion that has reached 60 ° C., which is the color change temperature of the temperature detection layer 5, and the color is clearly different from other regions in the temperature detection layer 5.

  Thus, the secondary battery 1 of the present embodiment detects not only an abnormality in which the entire battery has increased to an abnormal temperature, but also an abnormality in which only a part of the battery has locally increased to an abnormal temperature. Can do. In addition, the entire secondary battery 1 can be detected simply by visual inspection without using a special inspection device or carefully observing.

  In particular, the entire outer surface of the battery body 4 excluding the electrode terminals 2 and 3 is provided over the entire surface, so that any part of the battery body 4 rises to an abnormal temperature. It can be detected.

  In addition, since the position where the trouble has occurred can be identified from the discolored portion of the temperature detection layer 5 in the secondary battery 1, it helps to clarify the cause of the trouble. That is, in the case of a trouble inside the battery, it can be inferred in which part inside the secondary battery 1 an abnormality has occurred. If the trouble is outside the battery, it can also be estimated which part of the charge / discharge circuit or the like outside the secondary battery 1 has an abnormality. The occurrence of trouble outside the battery can be detected and dealt with while the phenomenon is small, so that more serious trouble can be prevented.

  FIG. 5 shows a secondary battery 10 in which the temperature detection layer 5 is applied to a cylindrical battery secondary battery. FIG. 5 is a perspective view showing an overview of the secondary battery 10. The secondary battery 10 is a cylindrical lithium-ion battery in which the battery body 11 forms a cylindrical shape. In this case, as in the secondary battery 1 of the first embodiment, the battery body excluding the electrode terminals 2 and 3 is used. In this configuration, the temperature detection layer 5 is provided on the entire outer surface of 11.

  In the case of a cylindrical battery, the temperature detection layer 5 is provided over the entire surface on at least one of the electrode terminal formation surfaces or one projection surface of the peripheral surface.

  Here, the secondary battery 10 is a 18650 type cylindrical lithium ion battery size, but the size is not limited to this. The battery configuration may be other configurations such as a nickel metal hydride battery, but as described above, a combination with a lithium ion battery is effective.

In FIG. 6, when the secondary battery 10 of the present embodiment has a trouble inside the secondary battery 10 or a trouble outside the secondary battery 10, the temperature of the outer surface of the battery body 11 rises, and the temperature detection layer 5 Shows the state of irreversible discoloration. The portion indicated by reference numeral 8 is a portion that has reached 60 ° C., which is the color change temperature of the temperature detection layer 5.
[Second Embodiment]
Another embodiment of the present invention will be described with reference to FIGS. For convenience of explanation, members having the same functions as those used in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  If the battery case is made of metal or the like and has excellent thermal conductivity, it is possible to transmit abnormal heat generated on the surface other than the surface provided with the temperature detection layer 5 to the surface provided with the temperature detection layer 5. . However, when the thermal conductivity of the battery case is low, or even if the battery case is made of metal, the battery size is increased and the surface on which the temperature detection layer 5 is provided is far from the temperature rise portion, the temperature detection layer 5 It may be assumed that the heat is not transmitted to

  In addition, in the secondary battery 1 attached to a fixing jig for fixing the secondary battery 1, when a temperature rise occurs in a portion hidden by the fixing jig, the secondary battery 1 is provided at a position where it can be visually observed. This heat can be detected by being transmitted to the temperature detecting layer 5 formed. However, if this heat is not transmitted, this abnormality cannot be detected unless the secondary battery 1 is removed from the fixing jig. The same applies to the case where the secondary battery 1 constitutes an assembled battery and the outer surfaces are hidden between adjacent batteries.

  In the present embodiment, a device for effectively transferring the heat of the temperature rising portion to the separated temperature detection layer 5 will be described.

  FIG. 7A is a perspective view showing an overview of the secondary battery 12 of the present embodiment. The secondary battery 12 of the present embodiment has the same configuration as the secondary battery 1 of the first embodiment, and further detects a temperature increase occurring at an invisible position at a position where it can be visually observed. It is the structure in which the heat conducting wire 15 for making it possible was provided. In FIG. 7A, hatching of the temperature detection layer 5 is omitted.

  FIG.7 (b) is the figure which extracted only the heat conducting wire 15 in Fig.7 (a). As shown in FIG.7 (b), in the secondary battery 12 of this embodiment, the heat conducting wire 15 consists of three of the 1st-3rd wires 15a-15c.

  The first line 15a goes around the battery body 4 in the vertical direction (viewed from the front) so as to bisect the front of the battery body 4 vertically between the electrode terminals 2 and 3 of the secondary battery 12. ing. Here, the front surface of the battery body 4 is defined as the widest surface of the battery body 4 (in the above-described size example, the surface is horizontal 170 × height 115).

  The second line 15b goes around the battery main body 4 in the horizontal direction (viewed from the front) so that the front of the battery main body 4 is divided into two in the horizontal direction. The second line 15b and the first line 15a intersect with each other on the front and back surfaces of the battery body 4.

  The third line 15c is configured so that the battery body 4 is circumferentially (viewed from the front) so that the side surface of the battery body 4 (in the above-described size example, the vertical (depth) 44 × height 115 surface) is vertically divided into two. ) 3/4 rounds except for the surface on which the electrode terminals 2 and 3 are formed. The third line 15 c and the second line 15 b cross each other on both sides of the battery body 4.

  Such a heat conducting wire 15 may be provided on either the upper layer or the lower layer of the temperature detection layer 5 as long as it is in contact (preferably in close contact) with the temperature detection layer 5.

  The heat conducting wire 15 is for transferring the heat of the local temperature rising portion generated at an invisible position to a region other than the temperature rising portion, and the local temperature rising generated at an invisible position. This makes it possible to detect the abnormality caused by Therefore, the material of the heat conducting wire 15 needs to be a material having a higher thermal conductivity than the material constituting the outer surface of the battery body 4.

  Usually, a metal such as SUS304 is used as a battery case in a secondary battery. Therefore, for example, copper, silver, gold, aluminum or the like having higher thermal conductivity than SUS304 can be used for the heat conducting wire 15.

  In the secondary battery 12 of the present embodiment, a copper wire having a width of 2 mm and a thickness of 100 μm was used as the heat conducting wire 15 and disposed on the temperature detection layer 5. By forming the heat conducting wire 15 in a ribbon shape with a thin thickness with respect to the line width, the heat conducting wire 15 is prevented without preventing the batteries from being in contact with each other or arranged close to each other. The discoloration of the temperature detection layer 5 due to heat from can be easily recognized.

  The width of the heat conducting wire 15 may be a width that allows the portion where the temperature detection layer 5 is discolored by heat from the heat conducting wire 15 to be visually recognized. Further, it is desirable that the thickness of the heat conducting wire 15 be reduced as long as the strength is maintained.

  In FIG. 8, the secondary battery 12 of this embodiment has a problem in the secondary battery 12 or a trouble in the secondary battery 12, and the temperature of the outer surface of the battery body 4 rises. Shows the state of irreversible discoloration. The portion indicated by reference numeral 9 is a portion that has reached 60 ° C., which is the color change temperature of the temperature detection layer 5. Further, the hatched portion indicated by reference numeral 16 is a portion where the heat of the portion indicated by reference numeral 9 is transmitted to the heat conducting wire 15 and is discolored along the heat conducting wire 15 by the heat (60 ° C. or higher). In FIG. 8, the temperature detection layer 5 is not hatched.

  Even if the temperature detection layer 5 is provided on the entire outer surface of the battery body 4, the battery size is large even when the battery case has a low thermal conductivity or even a battery case made of metal, and the fixing jig 30. When the temperature rises in the portion hidden by the heat, the heat is not transmitted to the temperature detection layer 5 provided at a visible position, and this may not be detected.

  However, as shown in FIG. 8, in the secondary battery 12 of the present embodiment provided with the heat conducting wire 15, a temperature rise occurs in a portion indicated by reference numeral 9 that is hidden by the fixing jig 30 or the like. Even so, the heat is transmitted through the heat conducting wire 15 and discolors the temperature detection layer 5 at a visible position as indicated by reference numeral 16, so that the secondary battery 1 is not removed from the fixing jig 30. , You can easily detect abnormalities.

  As a layout of the heat conducting wire 15, a heat conducting wire 15-1 shown in FIG. 9 may be arranged so as to draw a mesh with a pitch narrower than the layout of FIG. Thereby, the heat conducting wire 15 is not arranged in the portion where the temperature rise has occurred, and it is possible to avoid the problem that the abnormality of the hidden portion cannot be pulled out to a visible position.

  That is, the layout such as the number of wires and the arrangement position in the heat conducting wire 15 is a region size where a local temperature rise assumed in the secondary battery 12 occurs, a position that can be viewed in a fixed state with a fixing jig, and the like. Based on the above, it may be designed so that the temperature rise generated in the invisible portion can be derived to the visible position.

  The heat conducting wire 15 may be configured by winding a metal wire such as a copper wire around the battery body 4 or may be formed by printing. In particular, when the temperature detection layer 5 is composed of a thermo-seal, the heat-conducting wire 15 is previously formed on the thermo-seal by using a method such as printing, so that the heat-conducting wire 15 is simultaneously applied in the step of attaching the thermo-seal. Can be provided. Moreover, since the heat conducting wire 15 formed by printing is in close contact with the temperature detecting layer 5, the reaction of the temperature detecting layer 5 by the heat transmitted to the heat conducting wire 15 is performed sharply.

  FIG. 10A shows a configuration of the secondary battery 21 of the present embodiment in which the heat conductive wire 15-2 is provided in the cylindrical secondary battery 10 shown in the first embodiment. In FIG. 10A, the temperature detection layer 5 is not hatched.

  FIG.10 (b) is the figure which extracted only the heat conducting wire 15-2 in Fig.10 (a). As shown in FIG. 10B, the heat conducting wire 15-2 of the secondary battery 21 of the present embodiment is composed of three wires, a first to a third wire 15-2a to 15-2c.

The first line 15-2a and the second line 15-2b are disposed so as to face the outer surface (excluding the electrode terminal) of the cylindrical battery body 11 of the secondary battery 21 with the center of the cylinder interposed therebetween. ing. The first wire 15-2a and the second wire 15-2b are cylindrical battery bodies 11 extending from the surface on which the positive electrode terminal 2 is provided to the surface on which the negative electrode terminal 3 is provided. Has a length equivalent to that of the shaft in the axial direction.

  The third line 15-2c goes around the battery body 11 in the circumferential direction so as to bisect the cylindrical battery body 11 in a direction orthogonal to the axial direction. The third line 15-2 c, the first line 15-2 a, and the second line 15-2 b intersect with each other on the outer peripheral surface of the battery body 11.

  In FIG. 11, when the secondary battery 21 of the present embodiment is in trouble inside the secondary battery 21 or trouble outside the secondary battery 21, the temperature of the outer surface of the battery body 11 rises and the temperature detection layer 5 is Shows the state of irreversible discoloration. A portion indicated by reference numeral 17 is a portion that has reached 60 ° C., which is the color change temperature of the temperature detection layer 5. Further, the hatched portion indicated by the reference numeral 18 is transferred to the heat conducting wire 15-2 by the heat of the portion indicated by the reference symbol 17, and is discolored along the heat conducting wire 15-2 by the heat (60 ° C. or higher). Part. In FIG. 11, hatching of the temperature detection layer 5 is also omitted.

  Thus, also in the secondary battery 21 of the present embodiment, the abnormality of the portion hidden by the fixing jig 30 or the like is pulled out to a position where it can be visually observed and is transmitted as a discoloration of the temperature detection layer 5. Abnormalities can be easily detected without removing the secondary battery 21 from the fixing jig 30.

  Also in the present embodiment, which is an example of a cylindrical battery, the layout such as the number of heat conducting wires and the arrangement position is determined according to the region size and fixing jig in which a local temperature rise assumed in the secondary battery 21 occurs. What is necessary is just to design so that the temperature rise which generate | occur | produced in the part which cannot be seen can be derived | led-out to the position which can be visually observed based on the position etc. which can be visually observed in the fixed state.

For example, as shown in FIG. 12, by arranging a plurality of meshes at a pitch narrower than that shown in FIG. 10 (a), such as the heat conducting wire 15-3, the heat conducting wire 15 is arranged at the portion where the temperature rise has occurred. Therefore, it is possible to avoid the problem that the abnormality of the hidden part cannot be pulled out to a position where it can be visually observed.
[Third Embodiment]
Another embodiment of the present invention will be described with reference to FIGS. For convenience of explanation, members having the same functions as those used in the first and second embodiments are denoted by the same reference numerals and description thereof is omitted.

  In the present embodiment, the four types of secondary batteries described in the first and second embodiments, that is, the secondary battery (square type) 1, the secondary battery (cylindrical type) 10, and the secondary battery (square type). The assembled battery of each of the type 12 and the secondary battery (cylindrical type) 21 will be described.

  FIG. 13 shows a battery arrangement example of the assembled battery 23 using the prismatic secondary battery 1 of the first embodiment. In the example of FIG. 13, the example of 5 series 2 parallel is shown. As described above, the assembled battery is configured by combining a plurality of secondary batteries in series or in parallel in order to extract the voltage and power necessary for the device, and thus the assembling method is limited to this. is not.

  Here, five secondary batteries 1 constituting five series are composed of an upper fixing jig 31b and a lower fixing jig 31a made of ABS resin or polycarbonate, for example. The serial unit 24 is configured.

  FIG. 14 shows a connection configuration between electrode terminals in an assembled battery 23 in which a plurality of secondary batteries 1 are arranged as shown in FIG. In the figure, reference numeral 32 indicates a terminal connection line. In the terminal connection line 32, the five secondary batteries 1 in the series unit 24 are directly connected, and the two series units 24 are connected in parallel.

  FIG. 15 shows an assembled battery 25 using the secondary battery 12 of the second embodiment provided with a heat conducting wire 15 instead of the secondary battery 1. In the assembled battery 25 composed of the secondary battery 12 provided with the heat conducting wire 15, a temperature rise generated in an invisible portion can be detected by transferring heat to the heat conducting wire 15, so that the secondary battery 12 remains assembled. The presence or absence of abnormality of each secondary battery 12 can be determined.

  FIG. 16 shows a battery arrangement example of the assembled battery 40 using the cylindrical secondary battery 10 of the first embodiment. The example of FIG. 16 also shows an example of 5 series and 2 parallel. In the case of the cylindrical secondary battery 10, in the series unit 41, the five secondary batteries 10 are arranged so that plus and minus are alternated.

  Here again, the five secondary batteries 10 constituting the 5 series are composed of, for example, an ABS resin or polycarbonate, and the upper and lower fixing jigs 35b and 35a are fixed at the upper and lower parts. The serial unit 41 is configured.

  FIG. 17 shows a connection configuration between electrode terminals in the assembled battery 40 in which the secondary battery 10 is arranged as shown in FIG. In the figure, reference numeral 36 indicates a terminal connection line. In the terminal connection line 36, the five secondary batteries 1 in the series unit 41 are directly connected, and the two series units 41 are connected in parallel.

  FIG. 18 shows an assembled battery 42 using the secondary battery 21 of the second embodiment in which the heat conducting wire 15 is provided instead of the secondary battery 10. In the assembled battery 42 including the secondary battery 21 provided with the heat conducting wire 15, it is possible to detect a temperature rise generated at a portion that cannot be visually observed by the heat conducting wire 15, so that each secondary battery remains in the state where the secondary battery 12 is assembled. The presence or absence of 12 abnormalities can be determined.

  Further, as a more preferable configuration, the upper fixing jig 31b and the lower fixing jig 31a, the upper fixing jig 35b and the lower fixing jig 35a in the series unit 24 and the series unit 41 are as shown in FIGS. In addition, a transparent upper fixing jig 51b / lower fixing jig 51a, an upper fixing jig 52b, and a lower fixing jig 52a are used.

  According to this, even in the assembled batteries 23 and 40 including the rectangular secondary battery 1 without the heat conducting wire 15 or the cylindrical secondary battery 10, the portion that cannot be visually recognized by the fixing jig is greatly reduced. be able to. It is effective in the assembled battery of the secondary batteries 1, 10, 12, and 21 having the temperature detection layer 5 to make such a fixing jig transparent.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Secondary battery 2 Positive electrode terminal 3 Negative electrode terminal 4 Battery main body 5 Temperature detection layer 10 Secondary battery 11 Battery main body 12 Secondary battery 15 Heat conducting wire 21 Secondary battery 51a Lower fixing jig (fixing jig)
51b Upper fixing jig (fixing jig)
52a Lower fixing jig (fixing jig)
52b Upper fixing jig (fixing jig)

Claims (9)

  A secondary battery comprising a temperature detection layer that is irreversibly discolored by heating over at least one surface of a battery main body excluding electrode terminals.   The secondary battery according to claim 1, wherein the temperature detection layer is provided over the entire surface of the battery body.   The secondary battery according to claim 1, wherein the temperature detection layer is provided on all surfaces of the battery body over the entire surface. The battery body is provided with a heat conducting wire made of a material having a higher thermal conductivity than the material constituting the outer surface of the battery so as to come into contact with the temperature detection layer,
4. The secondary battery according to claim 1, wherein the heat conducting wire transfers heat of a locally generated temperature rising portion to a region other than the temperature rising portion. 5. .   The secondary battery according to claim 4, wherein the heat conducting wire has a ribbon shape with a thin thickness with respect to a line width.   The secondary battery according to any one of claims 1 to 5, wherein the secondary battery is a lithium ion battery.   The secondary battery according to any one of claims 1 to 6, further comprising a fixing jig for fixing the secondary battery, wherein the fixing jig is made of a transparent member.   A battery pack comprising a plurality of the secondary batteries according to any one of claims 1 to 6 connected in parallel, in series, or in both parallel and series.   The assembled battery according to claim 8, further comprising: a fixing jig that fixes a plurality of secondary batteries, wherein the fixing jig is made of a transparent member.

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