JP2008021569A - Secondary battery system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary battery system capable of improving the output characteristics of a secondary battery by efficiently heating the secondary battery. <P>SOLUTION: This secondary battery system 200 includes: the secondary battery 100; a first heating element 210 for heating a first adjacent part 110b of the secondary battery 100; a second heating element 220 for heating a second adjacent part 110c; a first temperature detection element 230 for outputting a first proximity part temperature signal according to the temperature of the first proximity part 110b; a second temperature detection element 240 for outputting a second proximity part temperature signal according to the temperature of the second proximity part 110c; and a control device 250 for controlling the heating of the first heating element 210 and the second heating element 220 based on the first proximity part temperature signal and the second proximity part temperature signal to reduce the difference between the temperature of the first proximity part 110b and that of the second proximity part 110c. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a secondary battery system.

Secondary batteries such as lithium ion secondary batteries are attracting attention as power sources for portable devices and portable devices, and as power sources for electric vehicles and hybrid vehicles.
However, a secondary battery such as a lithium ion secondary battery has a problem that the discharge capacity is reduced at a low temperature, and good output characteristics cannot be obtained. For this reason, when the secondary battery is used as a power source of, for example, an electric vehicle or a hybrid vehicle, there is a problem that an output cannot be sufficiently obtained in an environment where the temperature is below freezing point such as a cold district.
In order to solve this problem, in recent years, many techniques for heating a secondary battery by providing a heating element in the secondary battery have been proposed (for example, see Patent Document 1).

JP 2002-260745 A

  Patent Document 1 discloses a battery in which a heating element is attached to a terminal block of an electrode terminal protruding outside the battery case. In this battery, since the terminal block and the like are heated by the heat generated by the heating element, this heat is used to generate a power generation element (a positive electrode plate, a negative electrode plate, and an electrode body formed by winding a separator through a current collector connection body). ) Can be smoothly transmitted to the electrode, and the inside of the power generation element can be quickly warmed. Thus, it is described that the output characteristics of the battery can be promptly improved even when the temperature is low.

  By the way, in the secondary battery, a temperature difference may occur between the end on the positive electrode terminal side and the end on the negative electrode terminal side of the electrode body during charging and discharging. For example, in a lithium ion secondary battery, the temperature of the end portion on the negative electrode terminal side of the electrode body tends to be lower during charging than the end portion on the positive electrode terminal side. In such a case, as in Patent Document 1, even if the positive electrode terminal side and the negative electrode terminal side of the electrode body are heated equally, the end part on the positive electrode terminal side and the end part on the negative electrode terminal side of the electrode body are still The temperature difference remains.

  On the other hand, when the present inventors examined, for example, for a lithium ion secondary battery, when the amount of power supplied to the heating element is equal, the end on the positive electrode current collector member side and the negative electrode current collector member side Compared to the case where both ends are heated equally despite the difference in temperature between the ends (Patent Document 1), the end on the positive electrode current collector member side and the end on the negative electrode current collector member side of the electrode body It has been found that controlling and heating so that the temperature difference between the parts becomes smaller (for example, the temperatures at both ends become equal) can improve the discharge capacity of the secondary battery and improve the output characteristics. .

  This invention is made | formed in view of this present condition, Comprising: It aims at providing the secondary battery system which can improve the output characteristic of a secondary battery with sufficient heating efficiency.

  The solution includes an electrode body having a first end and a second end, and a battery case that houses the electrode body, and at least one of charging and discharging at the time of the first of the electrode bodies. A secondary battery in which a temperature at two ends is lower than a temperature at the first end, and at least the second end of the first end and the second end of the electrode body, Alternatively, a heating means for indirectly heating, a temperature detection means for outputting a first signal corresponding to the temperature of the first end, and a second signal corresponding to the temperature of the second end, and the first signal And a control means for controlling heating by the heating means based on the second signal and reducing a temperature difference between the first end portion and the second end portion.

  Among the secondary batteries, there is a secondary battery in which the temperature of the second end of the electrode body is lower than the temperature of the first end at least during charging and discharging. In such a secondary battery, there is a possibility that good output characteristics may not be obtained, for example, the discharge capacity becomes small particularly during low temperature operation. The reason is considered to be that the battery reaction is difficult to proceed in the vicinity of the second end portion where the temperature is low in the electrode body.

  On the other hand, the secondary battery system of the present invention includes a heating unit that directly or indirectly heats at least the second end of the first end and the second end of the electrode body. Temperature detection means is provided for outputting a first signal corresponding to the temperature and a second signal corresponding to the temperature of the second end. In addition, control means for controlling the heating by the heating means based on the first signal and the second signal and reducing the temperature difference between the first end and the second end is provided. Thereby, in the battery system of this invention, the temperature of the 2nd edge part of an electrode body can be closely approached to the temperature of a 1st edge part, and the temperature difference of a 1st edge part and a 2nd edge part can be made small.

  Therefore, according to the secondary battery system of the present invention, when the heating amount (for example, power supply amount) by the heating means (for example, a heating element) is made equal, the first end portion and the second end of the electrode body are the same. Compared to a secondary battery system in which the first end and the second end are heated equally (or the entire secondary battery is heated equally) despite the temperature difference between the two The discharge capacity of the secondary battery can be improved and the output characteristics can be improved. That is, the secondary battery system of the present invention can improve the output characteristics of the secondary battery with higher heating efficiency than the conventional secondary battery system.

  In addition, as an electrode body, for example, a first electrode plate (for example, a positive electrode plate) and a second electrode plate (for example, a negative electrode plate) having a different potential are laminated via a separator. An electrode body can be mentioned. Specifically, a wound electrode body formed by laminating a belt-shaped first electrode plate and a second electrode plate with a separator interposed therebetween, and a plurality of first electrode plates, For example, a laminated electrode body in which a plurality of second electrode plates are alternately laminated one by one with a separator interposed therebetween.

Moreover, as a temperature detection means, temperature detection elements, such as a thermistor and a thermocouple, can be used, for example.
In addition, only the second end portion may be heated by a heating means (for example, a heating element), but the output of the secondary battery is more when both the first end portion and the second end portion are heated. It is preferable because the characteristics can be further improved. It is because the temperature of the whole electrode body can be raised rather than the case where only the 2nd edge part is heated.

Furthermore, in the above secondary battery system, the control means is configured to make the temperature of the first end and the second end equal based on the first signal and the second signal. A secondary battery system that controls heating by the heating means is preferable.
If the control means controls the temperature of the first end and the second end to be equal, the temperature of the second end of the electrode body can be appropriately made substantially equal to the temperature of the first end. Become. Thereby, the output characteristic of a secondary battery can be improved much more efficiently.

  Furthermore, in any one of the above secondary battery systems, the heating means includes a first proximity portion, a second proximity portion of the outer wall portion of the battery case that is close to the first end portion of the electrode body, and the second proximity portion. When the part close to the end is the second proximity part, it is a heating means for heating at least the second proximity part among the first proximity part and the second proximity part, and the temperature detection means is Temperature detecting means for outputting a first proximity part temperature signal corresponding to the temperature of the first proximity part and a second proximity part temperature signal corresponding to the temperature of the second proximity part, wherein the control means A secondary control unit that controls heating by the heating unit based on the first proximity unit temperature signal and the second proximity unit temperature signal and reduces a temperature difference between the first proximity unit and the second proximity unit. A battery system is recommended.

  In the secondary battery system of the present invention, the heating means heats at least the second proximity portion of the first proximity portion and the second proximity portion of the outer wall portion of the battery case. Accordingly, at least the second end portion of the first end portion and the second end portion of the electrode body can be appropriately heated through the second proximity portion. Further, the temperature detecting means outputs a first proximity portion temperature signal corresponding to the temperature of the first proximity portion and a second proximity portion temperature signal corresponding to the temperature of the second proximity portion, and the control means outputs the first proximity portion temperature signal. Based on the 1 proximity part temperature signal and the 2nd proximity part temperature signal, the heating by a heating means is controlled and the temperature difference of a 1st proximity part and a 2nd proximity part is made small. Thereby, the temperature of the 2nd edge part of an electrode body can be closely approached to the temperature of a 1st edge part appropriately.

Furthermore, in the above secondary battery system, the control unit is configured to control the temperature of the first proximity part and the second proximity part based on the first proximity part temperature signal and the second proximity part temperature signal. It is preferable that the secondary battery system controls heating by the heating means so as to be equal.
By controlling the temperature of the first proximity portion and the second proximity portion to be equal by the control means, the temperature of the second end portion of the electrode body can be appropriately made substantially equal to the temperature of the first end portion. Become. Thereby, the output characteristic of a secondary battery can be improved much more efficiently.

  Furthermore, in any one of the secondary battery systems, as the heating means, first heating means for directly or indirectly heating the first end portion of the electrode body, and the second end of the electrode body. The unit may be a secondary battery system including a second heating unit that directly or indirectly heats the unit.

In the secondary battery system of the present invention, the first end of the electrode body is directly or indirectly heated by the first heating means, and the second end of the electrode body is directly or indirectly heated by the second heating means. For this reason, compared with the case where only the 2nd edge part of an electrode body is heated, the output characteristic of a secondary battery can be improved further. It is because the temperature of the whole electrode body can be raised rather than the case where only a 2nd edge part is heated.
The case where the first end portion of the electrode body is indirectly heated by the first heating means is, for example, a case where the first proximity portion of the battery case is heated. The case where the second end portion of the electrode body is indirectly heated by the second heating means is, for example, a case where the second proximity portion of the battery case is heated.

  Another solution includes a first electrode plate having a first electrode substrate and a second electrode substrate having a lower electrical resistance than the first electrode substrate, and a potential different from that of the first electrode plate. A second electrode plate and a separator, and an electrode body formed by laminating the first electrode plate and the second electrode plate with the separator interposed therebetween, and collects electric charges of the first electrode plate A first current collecting member, a second current collecting member for collecting electric charges of the second electrode plate, and a battery case that accommodates the electrode body, the first current collecting member, and the second current collecting member therein The electrode body comprises a laminated portion formed by laminating the first electrode plate, the second electrode plate, and the separator, and the first electrode plate from the laminated portion, Of the second electrode plate and the separator, only a part of the first electrode plate protrudes from the first end. Only a part of the second electrode plate out of the first electrode plate, the second electrode plate, and the separator protrudes from the first end portion joined to the first current collecting member and the stacked portion. A secondary battery having a second end portion joined to the second current collecting member, and an outer wall portion of the battery case, wherein the first end of the electrode body is included in the second end portion. When the part close to the end is the first proximity part and the part close to the second end is the second proximity part, at least the second proximity part of the first proximity part and the second proximity part A heating element fixed to the first proximity detecting element, a first temperature sensing element that outputs a first proximity part temperature signal corresponding to the temperature of the first proximity part, and a second proximity part temperature corresponding to the temperature of the second proximity part. A second temperature detecting element that outputs a signal, the first proximity part temperature signal, and the second proximity part temperature signal; Zui and to control the power supply to the heating element, and a control means for reducing the temperature difference between the second proximate portion and the first proximity unit is a rechargeable battery system comprising a.

  The secondary battery system of the present invention includes a first electrode plate having a first electrode substrate, a second electrode plate having a second electrode substrate having a lower electrical resistance than the first electrode substrate, and a separator. And a secondary battery including an electrode body laminated. Further, the secondary battery includes a first end portion in which only a part of the first electrode plate protrudes from the laminated portion, a first end portion joined to the first current collecting member, and the laminated portion. It has a second end formed by projecting only a part of the second electrode plate, and a second end joined by the second current collecting member. In such a secondary battery, the temperature of the second end portion of the electrode body tends to be lower than the temperature of the first end portion at least during charging and discharging. Therefore, the temperature of the portion located near the second end portion of the stacked portion of the electrode body tends to be lower than the temperature of the portion located near the first end portion. For this reason, there is a possibility that good output characteristics cannot be obtained, for example, the discharge capacity becomes small, especially during low-temperature operation.

  On the other hand, in the secondary battery system of the present invention, a heating element is provided in at least the second proximity portion among the first proximity portion and the second proximity portion of the outer wall portion of the battery case, and the temperature is in accordance with the temperature of the first proximity portion. A first temperature detection element that outputs a first proximity part temperature signal; and a second temperature detection element that outputs a second proximity part temperature signal corresponding to the temperature of the second proximity part. In addition, control means is provided for controlling energization to the heating element based on the first proximity part temperature signal and the second proximity part temperature signal and reducing the temperature difference between the first proximity part and the second proximity part. Thereby, in the battery system of the present invention, the temperature of the second end of the electrode body is brought close to the temperature of the first end, and the temperature difference between the first end and its vicinity and the second end and its vicinity is reduced. be able to.

  Therefore, according to the secondary battery system of the present invention, when the amount of power supplied to the heating element is made equal, a temperature difference is generated between the first end and the second end of the electrode body. Compared to a secondary battery system in which the first end and the second end are heated equally (or the entire secondary battery is heated equally), the discharge capacity of the secondary battery is improved and the output characteristics are improved. Can be improved. That is, the secondary battery system of the present invention can improve the output characteristics of the secondary battery with higher heating efficiency than the conventional secondary battery system.

In addition, as an electrode body formed by laminating the first electrode plate and the second electrode plate via a separator, for example, a strip-shaped first electrode plate and a second electrode plate are interposed with a separator interposed therebetween. A wound electrode body obtained by laminating and winding can be given. Alternatively, a plurality of first electrode plates and a plurality of second electrode plates may be stacked one by one with a separator interposed therebetween, and may also be a stacked electrode body. Any element may be used as long as it outputs a first proximity part temperature signal corresponding to the temperature of the first proximity part. For example, a thermistor or a thermocouple can be used. The second temperature detection element is the same as the first temperature detection element.

Furthermore, in the above secondary battery system, the control unit is configured to control the temperature of the first proximity part and the second proximity part based on the first proximity part temperature signal and the second proximity part temperature signal. It is preferable that the secondary battery system controls the energization of the heating element so as to be equal.
By controlling the temperature of the first proximity portion and the second proximity portion to be equal by the control means, the temperature of the second end portion of the electrode body can be appropriately made substantially equal to the temperature of the first end portion. Become. Thereby, the output characteristic of a secondary battery can be improved much more efficiently.

  Furthermore, in any one of the secondary battery systems, the secondary battery includes the first electrode plate, the second electrode plate, and the separator, each having a belt shape, and the electrode body, The strip-shaped first electrode plate, the second electrode plate, and the separator are laminated and wound, and at the first end, only a part of the first electrode plate overlaps in a spiral shape, and the second At the end, a secondary battery system that is a secondary battery in which only a part of the second electrode plate overlaps in a spiral shape may be used.

  In the secondary battery system of the present invention, the secondary battery has an electrode body formed by laminating and winding a strip-shaped first electrode plate, a second electrode plate, and a separator as an electrode body. In the secondary battery system of the present invention, the output characteristics of the secondary battery can be improved with good heating efficiency even for the secondary battery having a wound electrode body.

  Further, in any one of the secondary battery systems, the heating element is fixed to the first heating element fixed to the first proximity part of the battery case and to the second proximity part of the battery case. In addition, the secondary battery system may include a second heating element.

  In the secondary battery system of the present invention, the first heating element heats the first end of the electrode body through the first proximity part of the battery case, and the second heating element causes the electrode to pass through the second proximity part of the battery case. The second end of the body can be heated. For this reason, compared with the case where only the 2nd edge part of an electrode body is heated through the 2nd proximity | contact part of a battery case, the output characteristic of a secondary battery can be improved further. This is because the temperature of the entire electrode body can be increased more quickly than when only the second end is heated.

  Furthermore, in any one of the secondary battery systems, the secondary battery is a lithium ion secondary battery in which the first electrode base material is made of aluminum and the second electrode base material is made of copper. A secondary battery system is preferable.

  The secondary battery system of the present invention includes a lithium ion secondary battery having a first electrode base made of aluminum and a second electrode base made of copper as a secondary battery. In this lithium ion secondary battery, the temperature of the second end tends to be lower than that of the first end of the electrode body during charging. In contrast, in the secondary battery system of the present invention, as described above, the temperature of the second end of the electrode body is brought close to the temperature of the first end, and the temperature difference between the first end and the second end is set. Can be small. Therefore, according to the secondary battery system of the present invention, the output characteristics of the lithium ion secondary battery can be improved with good heating efficiency.

(Example 1)
Next, Example 1 of the present invention will be described with reference to the drawings.
First, the secondary battery 100 according to the first embodiment will be described. As shown in FIG. 1, the secondary battery 100 of the first embodiment includes a rectangular sealed battery case 110 including a rectangular battery case 110, a safety valve 140, a positive electrode terminal 120, a negative electrode terminal 130, and an electrode body 150. It is a lithium ion secondary battery.

The battery case 110 is made of metal, and includes a rectangular housing portion 111 that forms a rectangular parallelepiped housing space, and a metal lid portion 112. The battery case 110 contains an electrode body 150, a positive current collector 122, a negative current collector 132, an electrolyte solution (not shown), and the like. The positive electrode current collecting member 122 and the negative electrode current collecting member 132 are elongated plate-shaped metal members, and are connected to the positive electrode terminal 120 and the negative electrode terminal 130, respectively. As the electrolytic solution, for example, an organic electrolytic solution obtained by adding LiPF ₆ as a solute to a mixed organic solvent of EC (ethylene carbonate) and DEC (diethyl carbonate) can be used.

  A through hole 112 b is formed in the lid portion 112. The through-hole 112b is sealed from the outside of the battery case 110 by a disc-shaped metal safety valve 140. Specifically, the safety valve 140 is welded onto the outer surface 112f of the lid portion 112 so as to seal the through hole 112b. As a result, when the internal pressure of the battery case 110 exceeds a predetermined valve opening pressure, the safety valve 140 is cleaved to open the seal of the battery case 110, and the gas in the battery case 110 can be discharged to the outside.

  The electrode body 150 is an oblong cross section, and is a flat wound body formed by winding a belt-like positive electrode plate 155, a negative electrode plate 156, and a separator 157. Specifically, the electrode body 150 is formed by winding a strip-shaped laminated body in which a positive electrode plate 155 and a negative electrode plate 156 are laminated via a separator 157 into a flat cross section. The electrode body 150 is positioned on the laminated portion 151 in which the positive electrode plate 155, the negative electrode plate 156, and the separator 157 overlap each other in a spiral shape and on one end side (right side in FIG. 1) in the axial direction (left-right direction in FIG. 1). The positive electrode winding part 155b in which only a part of the positive electrode plate 155 overlaps in a spiral shape and the negative electrode winding part 156b in the other end side (left side in FIG. 1) and only a part of the negative electrode plate 156 overlaps in a spiral shape. And have.

Among these, the positive electrode plate 155 has the positive electrode base material 155c which consists of aluminum foil, and the positive electrode compound material apply | coated to the site | part except the positive electrode winding part 155b among the surfaces of this positive electrode base material 155c. The positive electrode mixture includes a positive electrode active material (for example, LiCoO ₂ ), a conductive material (for example, acetylene black), and a binder resin (for example, PVDF). As shown in FIG. 1, the positive electrode current collector 122 is welded to the positive electrode winding portion 155b of the positive electrode plate 155 where the positive electrode mixture is not applied.

The negative electrode plate 156 includes a negative electrode base material 156c made of copper foil, and a negative electrode mixture applied to a portion of the surface of the negative electrode base material 156c excluding the negative electrode winding portion 156b. The negative electrode mixture includes a negative electrode active material (for example, graphite) and a binder resin (for example, PVDF). As shown in FIG. 1, the negative electrode current collecting member 132 is welded to the negative electrode winding part 156 b of the negative electrode plate 156 to which the negative electrode mixture is not applied.
As the separator 157, for example, a resin film made of PE (polyethylene) and PP (polypropylene) can be used.

  In such a secondary battery 100, since the electrical resistance of the negative electrode base material 156c made of copper foil is smaller than that of the positive electrode base material 155c made of aluminum foil, the negative electrode winding portion 156b of the electrode body 150 is charged during charging. Tends to be lower than the temperature of the positive electrode winding portion 155b. Therefore, in the stacked portion 151 of the electrode body 150, the temperature of the second stacked end portion 151c located near the negative electrode wound portion 156b is equal to the temperature of the first stacked end portion 151b located near the positive electrode wound portion 155b. It tends to be lower than

In Example 1, the positive electrode plate 155 is the first electrode plate, the negative electrode plate 156 is the second electrode plate, the positive electrode substrate 155c is the first electrode substrate, and the negative electrode substrate 156c is the second electrode substrate. Further, the positive electrode winding portion 155b corresponds to the first end portion, and the negative electrode winding portion 156b corresponds to the second end portion.
Further, in the outer wall portion 110d of the battery case 110 (the square housing portion 111 and the lid portion 112), a portion close to the positive electrode winding portion 155b (first end) of the electrode body 150 is defined as the first proximity portion 110b and the negative electrode winding. A part close to the part 156b (second end) is defined as a second proximity part 110c. Specifically, in FIG. 1, in the outer wall part 110d of the battery case 110, a part located on the right side of the first boundary line L1 is a part located on the left side of the first proximity part 110b and the second boundary line L2. It corresponds to the second proximity portion 110c.

  Next, the secondary battery system 200 according to the first embodiment will be described. As shown in FIG. 2, the secondary battery system 200 of the first embodiment includes a secondary battery 100, a first heating element 210, a second heating element 220, a first temperature detection element 230, and a second temperature. A detection element 240, a control device 250, and a power supply device 260 are provided. The first heating element 210, the second heating element 220, the first temperature detection element 230, and the second temperature detection element 240 are respectively the first terminal 251, the second terminal 252, and the second temperature detection element 240 of the control device 250. The third terminal 253 and the fourth terminal 254 are electrically connected.

  Among these, the first heating element 210 is a known heating element, and is fixed to the outer surface of the first proximity portion 110 b of the battery case 110. Therefore, by heating the first proximity part 110b of the battery case 110 by the first heating element 210, the positive electrode winding part 155b of the electrode body 150 can be heated through the first proximity part 110b. Thereby, the temperature of the 1st lamination | stacking edge part 151b located in the vicinity of the positive electrode winding part 155b among the lamination | stacking parts 151 of the electrode body 150 can be raised.

  The second heating element 220 is a heating element equivalent to the first heating element 210, and is fixed to the outer surface of the second proximity portion 110 c of the battery case 110. Therefore, by heating the second proximity part 110c of the battery case 110 by the second heating element 220, the negative electrode winding part 156b of the electrode body 150 can be heated through the second proximity part 110c. Thereby, the temperature of the 2nd lamination | stacking edge part 151c located in the vicinity of the negative electrode winding part 156b among the lamination | stacking parts 151 of the electrode body 150 can be raised.

The first temperature detection element 230 is a known thermocouple, and is fixed to the outer surface of the first proximity portion 110 b of the battery case 110. Therefore, the first temperature detection element 230 can output a first proximity portion temperature signal corresponding to the temperature of the first proximity portion 110b of the battery case 110.
The second temperature detection element 240 is a thermocouple equivalent to the first temperature detection element 230, and is fixed to the outer surface of the second proximity portion 110 c of the battery case 110. Accordingly, the second temperature detection element 240 can output a second proximity portion temperature signal corresponding to the temperature of the second proximity portion 110c of the battery case 110.

  The power supply device 260 is electrically connected to the positive terminal 120 and the negative terminal 130 of the secondary battery 100, and charges the secondary battery 100. Further, the power supply device 260 is also electrically connected to the control device 260, operates the control device 260, and supplies power to the first heating element 210 and the second heating element 220 through the control device 160.

  The control device 250 includes a ROM, a RAM, a CPU, and the like (not shown), a first proximity part temperature signal output from the first temperature detection element 230, and a second proximity part temperature output from the second temperature detection element 240. Based on the signal, the energization to the first heating element 210 and the second heating element 220 is controlled so that the temperature T1 of the first proximity part 110b of the battery case 110 is equal to the temperature T2 of the second proximity part 110c. To do. Further, the control device 250 can detect the battery voltage of the secondary battery 100 and detect the state of charge of the secondary battery 100.

  Here, the heating control of the secondary battery system 200 (control device 250) of the first embodiment will be described with reference to FIG. When charging of the secondary battery 100 is started, as shown in FIG. 3, the first proximity temperature signal output from the first temperature detection element 230 and the output from the second temperature detection element 240 are output in step S <b> 1. The second proximity portion temperature signal to be detected is detected. Subsequently, it progresses to step S2 and it is determined whether the temperature T1 of the 1st proximity part 110b of the battery case 110 is higher than the temperature T2 of the 2nd proximity part 110c (T1> T2?). If it is determined in step S2 that T1> T2 (YES), the process proceeds to step S3, the energization of the second heating element 220 is turned on, and the second proximity portion 110c is heated. On the other hand, when it is determined NO (T1 ≦ T2) in step S2, the process proceeds to step S4, the energization to the first heating element 210 is turned on, and the first proximity portion 110b is heated.

  Subsequently, it progresses to step S5 and it is confirmed whether charge to the secondary battery 100 was complete | finished. Specifically, the battery voltage of the secondary battery 100 is detected, and when the battery voltage reaches a predetermined value (a preset value of the battery voltage at the end of charging), it is determined that charging has ended. When it determines with charging (NO), it returns to step S2 and repeats the process of the above-mentioned step S2-S5. Thereafter, if it is determined in step S5 that charging is complete (YES), the process proceeds to step S6, the energization of the first heating element 210 and the second heating element 220 is turned off, and the energization control is terminated. In this way, in the secondary battery system 200 of the first embodiment, the first heating element 210 and the second proximity part 110c and the second proximity part 110c are equalized during charging of the secondary battery 100. The energization to the second heating element 220 is controlled.

  By the way, as described above, in the secondary battery 100 of Example 1, the temperature of the negative electrode winding part 156b in the electrode body 150 tends to be lower than the temperature of the positive electrode winding part 155b during charging. . For this reason, the temperature of the 2nd lamination | stacking edge part 151c located in the vicinity of the negative electrode winding part 156b among the lamination | stacking parts 151 of the electrode body 150 is the temperature of the 1st lamination | stacking edge part 151b located in the vicinity of the positive electrode winding part 155b. It tends to be lower than the temperature. In such a secondary battery, there is a possibility that good output characteristics may not be obtained, for example, the discharge capacity becomes small particularly during low temperature operation.

  On the other hand, in the secondary battery system 200 of the first embodiment, as described above, the first proximity unit 110b and the second proximity unit 110c are equal in temperature while the secondary battery 100 is being charged. Energization of the heating element 210 and the second heating element 220 is performed. Thereby, the temperature of the positive electrode winding part 155b and the negative electrode winding part 156b can be made substantially equal, while raising the temperature of the negative electrode winding part 156b and the positive electrode winding part 155b of the electrode body 150.

(Discharge capacity measurement test)
Next, for the secondary battery system 200 of Example 1, the discharge capacity of the secondary battery 100 in a low temperature environment of −25 ° C. was measured.
Specifically, first, the secondary battery system 200 of the first embodiment is placed in a thermostatic bath at −25 ° C. Subsequently, the secondary battery 100 was charged with a constant current-constant voltage for 1.5 hours by the power supply device 260 until the battery voltage became 4.1V. While the secondary battery 100 is being charged, as described above, the first heating element 210 and the second heating element are set so that the temperatures of the first proximity part 110b and the second proximity part 110c become equal by the processing of steps S1 to S6. The energization control to 220 was performed.

  During charging of the secondary battery 100, the amount of power supplied to the first heating element 220 and the second heating element 220 was 45.0 Wh in total. Moreover, when the temperature of the 1st proximity part 110b and the 2nd proximity part 110c was detected about the secondary battery 100 after charge, it became -3.5 degreeC and -3.4 degreeC, respectively, and has become the substantially equal temperature. It was. Thereafter, the secondary battery 100 was discharged at a current value of 1 C until the battery voltage reached 3V. When the discharge capacity at this time was measured, it was 10.23 Ah. The results are shown in Table 1.

(Example 2)
Next, the secondary battery system 300 according to Example 2 will be described. As shown in FIG. 4, the secondary battery system 300 of the second embodiment is different from the secondary battery system 200 of the first embodiment in that the first heating element 210 is not provided and the control device 250 is replaced. The control device 350 is provided, and the other parts are the same. In the second embodiment, unlike the first embodiment, the control device 350 supplies power only to the second heating element 220 while the secondary battery 100 is being charged, and the temperature of the first proximity portion 110b of the battery case 110 is determined. It controls so that the temperature of the 2nd proximity part 110c may become equal.

  Specifically, when charging of the secondary battery 100 is started, as shown in FIG. 5, in step U1, the first proximity portion temperature signal output from the first temperature detecting element 230 and the second temperature are displayed. The second proximity portion temperature signal output from the sensing element 240 is detected. Next, the process proceeds to step U2, and it is determined whether the temperature T1 of the first proximity portion 110b of the battery case 110 is higher than the temperature T2 of the second proximity portion 110c (T1> T2?). If it is determined in step U2 that T1> T2 (YES), the process proceeds to step U3, the energization of the second heating element 220 is turned on, and the second proximity portion 110c is heated.

  Subsequently, it progresses to step U5 and it is confirmed whether the charge to the secondary battery 100 was complete | finished. If it is determined that charging is in progress (NO), the process returns to step U2, and again whether or not the temperature T1 of the first proximity part 110b of the battery case 110 is higher than the temperature T2 of the second proximity part 110c (T1> T2?) Is determined. If it is determined in step U2 that T1> T2 (YES), the process proceeds to step U3, and energization of the second heating element 220 is maintained in an ON state. On the other hand, when it is determined NO (T1 ≦ T2) in step U2, the process proceeds to step U4, and the energization to the second heating element 220 is turned off.

  Thereafter, the processes in steps S1 to S6 described above are repeated. If it is determined in step U5 that the charging is completed (YES), the process proceeds to step U6, the energization to the second heating element 220 is turned off, and the energization control is performed. finish. In this way, in the secondary battery system 200 of the second embodiment, during charging of the secondary battery 100, the second heating element 220 is supplied so that the temperatures of the first proximity portion 110b and the second proximity portion 110c become equal. Control energization.

  For the secondary battery system 300 of Example 2, the discharge capacity measurement of the secondary battery 100 in a low temperature environment of −25 ° C. was performed in the same manner as Example 1. In the present Example 2, the discharge capacity of the secondary battery 100 was 10.23 Ah. In Example 2, during the charging of the secondary battery 100, the amount of power supplied to the second heating element 220 was 12.0 Wh. Moreover, when the temperature of the 1st proximity part 110b and the 2nd proximity part 110c was detected about the secondary battery 100 after charge, it became -16.5 degreeC and -16.3 degreeC, respectively, and has become the substantially equal temperature. It was. The results are shown in Table 1.

(Comparative Example 1)
As Comparative Example 1, during the charging of the secondary battery 100, the secondary battery 100 was not heated by the first heating element 210 and the second heating element 220 in the same manner as in Examples 1 and 2, at −25 ° C. A measurement test of the discharge capacity of the secondary battery 100 in a low temperature environment was performed. In Comparative Example 1, the discharge capacity of the secondary battery 100 was 7.64 Ah. In Comparative Example 1, when the temperatures of the first proximity part 110b and the second proximity part 110c were detected for the charged secondary battery 100, they were -16.4 ° C and -20.0 ° C, respectively. A temperature difference of 3.6 ° C. occurred. The results are shown in Table 1.

(Comparative Example 2)
In the comparative example 2, during the charging of the secondary battery 100, the first heating element 210 and the second heating element 220 are equal to each other without controlling the temperature T1 of the first proximity part 110b and the temperature T2 of the second proximity part 110c. By supplying electric power, the 1st proximity part 110b and the 2nd proximity part 110c were heated equally. Also in this comparative example 2, when the measurement test of the discharge capacity of the secondary battery 100 in a low temperature environment of −25 ° C. was performed in the same manner as in Examples 1 and 2, the discharge capacity of the secondary battery 100 was 7. It was 91 Ah. In the first comparative example, during the charging of the secondary battery 100, the total amount of power supplied to the first heating element 210 and the second heating element 220 is set to 12.0 Wh as in the second embodiment. Moreover, when the temperature of the 1st proximity part 110b and the 2nd proximity part 110c was detected about the secondary battery 100 after charge, it became -14.1 degreeC and -17.9 degreeC, respectively, and the temperature of 3.8 degreeC There was a difference. The results are shown in Table 1.

Here, the results of Examples 1 and 2 and Comparative Examples 1 and 2 will be examined with reference to Table 1.
From the result of Comparative Example 1, when the secondary battery 100 according to Examples 1 and 2 is charged, the temperature T2 of the second proximity part 110c is lower than the temperature T1 of the first proximity part 110b. Recognize. Therefore, in the secondary battery 100, during charging, the temperature of the second stacked end portion 151c located in the vicinity of the negative electrode winding portion 156b in the stacked portion 151 of the electrode body 150 is in the vicinity of the positive electrode winding portion 155b. It is considered that the temperature is lower than the temperature of the first laminated end portion 151b located at the position. For this reason, in Comparative Example 1, the discharge capacity was as small as 7.91 Ah, and good output characteristics could not be obtained.

  In the comparative example 2, unlike the comparative example 1, the first proximity after charging is compared with the comparative example 1 by heating the first proximity part 110b and the second proximity part 110c of the secondary battery 100 during charging. Both the temperature T1 of the part 110b and the temperature T2 of the second proximity part 110c could be increased. However, in the comparative example 2, during the charging of the secondary battery 100, the first proximity portion 110b and the second proximity portion are not controlled without controlling the temperature T1 of the first proximity portion 110b and the temperature T2 of the second proximity portion 110c. Since 110c was heated equally, T2 was 3.8 ° C. lower than T1 after charging. Moreover, in Comparative Example 2, the temperature difference between T1 and T2 after charging was extended by 0.2 ° C. compared with Comparative Example 1. In Comparative Example 2, the discharge capacity was 7.64 Ah, which was higher than that of Comparative Example 1 by 0.27 Ah.

  On the other hand, in Example 2, during the charging of the secondary battery 100, the discharge capacity was 8.38 Ah even though the same amount of electric power as that in Comparative Example 2 was supplied to the heating element, and compared with Comparative Example 1. The capacity could be increased by 0.74 Ah. That is, in Example 2 and Comparative Example 2, although the same amount of electric power was supplied to the heating element during charging of the secondary battery 100, in Comparative Example 2, the discharge capacity was 0.27 Ah compared to Comparative Example 1. However, in Example 2, the discharge capacity could be increased by 0.74 Ah compared to Comparative Example 1.

  From this result, when the heating amount (power supply amount) by the heating means (second heating element 220 or the like) is made equal, the temperature T1 of the first proximity portion 110b and the temperature T2 of the second proximity portion 110c of the secondary battery 100 are equal. However, the temperature difference between T1 and T2 is made smaller than in the case where the first proximity portion 110b and the second proximity portion 110c are heated equally (in the second embodiment, T1 It can be said that the discharge capacity of the secondary battery can be improved by heating the second proximity portion 110c so that T2 is equal to T2. That is, it can be said that the secondary battery system 300 according to Example 2 can improve the output characteristics of the secondary battery 100 with higher heating efficiency than the comparative example 2.

  Further, in Example 1, as in Example 2, heating control is performed so that the temperature T1 of the first proximity part 110b of the secondary battery 100 and the temperature T2 of the second proximity part 110c are equal. Unlike Example 1, not only the 2nd proximity part 110c but the 1st proximity part 110b is heated. As a result, T1 and T2 can be greatly increased, and the discharge capacity can be improved to 10.23 Ah. Compared with the discharge capacity of Comparative Example 1, it could be increased by 2.59 Ah. From this result, the temperature difference between the temperature T1 of the first proximity portion 110b and the temperature T2 of the second proximity portion 110c of the secondary battery 100 is reduced (in Example 1, T1 and T2 are made equal). It can be said that the discharge capacity of the secondary battery can be further improved by heating the first proximity portion 110b and the second proximity portion 110c.

  Furthermore, the increase rate X (Ah / Wh) of the discharge capacity per unit supply electric power with respect to Comparative Example 1 is compared between Example 1 and Comparative Example 2. In Comparative Example 2, by supplying a power amount of 12.0 Wh to the first heating element 210 and the second heating element 220, the discharge capacity could be increased by 0.27 Ah compared to Comparative Example 1. Therefore, the increase rate X of Comparative Example 2 is about 0.023 (Ah / Wh).

  On the other hand, in Example 1, it was possible to increase the discharge capacity by 2.59 Ah compared to Comparative Example 1 by supplying the power amount of 45.0 Wh to the first heating element 210 and the second heating element 220. . Therefore, the rate of increase X in Example 1 was about 0.058 (Ah / Wh), which was about 2.6 times that of Comparative Example 2. From this result, it can be said that the secondary battery system 200 according to Example 1 can improve the output characteristics of the secondary battery 100 with higher heating efficiency than the comparative example 2.

  In the above, the present invention has been described with reference to the first and second embodiments. However, the present invention is not limited to the above-described embodiments, and it can be applied as appropriate without departing from the scope of the present invention. Nor.

  For example, in the secondary batteries 100 of Examples 1 and 2, a wound electrode body 150 in which a belt-like positive electrode plate 155, a negative electrode plate 156, and a separator 157 are stacked and wound is used as the electrode body. However, the form of the electrode body may be any form, for example, a stacked electrode body in which a plurality of positive plates 155 and a plurality of negative plates 156 are alternately stacked via separators 157 one by one.

  In the first and second embodiments, the secondary battery system 200 using the lithium ion secondary battery as the secondary battery 100 is illustrated. However, the present invention is not limited to any secondary battery as long as it is a secondary battery in which the temperature of the second end of the electrode body is lower than the temperature of the first end at least during charging and discharging. The present invention can also be applied to a battery. For a secondary battery in which the temperature of the second end is lower than the temperature of the first end during discharge, it is preferable to heat at least the second end (second proximity portion) during discharge.

  In the secondary battery systems 200 and 300 of the first and second embodiments, the first heating element 210 is configured such that the temperature T1 of the first proximity portion 110b of the battery case 110 is equal to the temperature T2 of the second proximity portion 110c. In addition, energization of at least the second heating element 220 among the second heating elements 220 was controlled. However, the temperature T1 of the first proximity part 110b and the temperature T2 of the second proximity part 110c are not controlled so that the temperature T1 of the first proximity part 110b is equal to the temperature T2 of the second proximity part 110c. The energization control may be performed so that the difference becomes small. As the temperature difference between T1 and T2 is reduced, the discharge capacity of the secondary battery can be improved.

1 is a cross-sectional view of a secondary battery 100 according to Examples 1 and 2. FIG. 1 is a diagram showing a configuration of a secondary battery system 200 according to Example 1. FIG. 3 is a flowchart illustrating a flow of heating control according to the first embodiment. 6 is a diagram showing a configuration of a secondary battery system 300 according to Example 2. FIG. 6 is a flowchart illustrating a flow of heating control according to the second embodiment.

Explanation of symbols

100 Secondary Battery 110 Battery Case 110b First Proximity Part 110c Second Proximity Part 110d Outer Wall Part 122 Positive Current Collector (First Current Collector)
132 Negative electrode current collector (second current collector)
150 Electrode body 151 Lamination | stacking part 155 Positive electrode plate (1st electrode plate)
155b Positive electrode winding part (first end)
155c Positive electrode base material (first electrode base material)
156 Negative electrode plate (second electrode plate)
156b Negative electrode winding part (second end part)
156c Negative electrode substrate (second electrode substrate)
157 Separator 200 Secondary battery system 210 First heating element (first heating means)
220 Second heating element (second heating means)
230 1st temperature detection element (temperature detection means)
240 Second temperature detection element (temperature detection means)
250 Control device (control means)

Claims (7)

An electrode body having a first end portion and a second end portion, and a battery case that houses the electrode body, and at least one of charging and discharging, the temperature of the second end portion of the electrode body. A secondary battery that is lower than the temperature of the first end,
Heating means for directly or indirectly heating at least the second end portion of the first end portion and the second end portion of the electrode body;
A temperature detection means for outputting a first signal corresponding to the temperature of the first end and a second signal corresponding to the temperature of the second end;
A secondary battery system comprising: control means for controlling heating by the heating means based on the first signal and the second signal and reducing a temperature difference between the first end portion and the second end portion. . The secondary battery system according to claim 1,
The heating means includes
Of the outer wall portion of the battery case, when the portion close to the first end of the electrode body is the first proximity portion and the portion close to the second end is the second proximity portion, the first proximity A heating means for heating at least the second proximity portion of the first proximity portion and the second proximity portion,
The temperature detecting means includes
Temperature detecting means for outputting a first proximity portion temperature signal corresponding to the temperature of the first proximity portion and a second proximity portion temperature signal corresponding to the temperature of the second proximity portion;
The control means includes
Control means for controlling heating by the heating means on the basis of the first proximity part temperature signal and the second proximity part temperature signal to reduce a temperature difference between the first proximity part and the second proximity part. Secondary battery system. The secondary battery system according to claim 1 or 2,
As the heating means,
First heating means for directly or indirectly heating the first end of the electrode body;
A secondary battery system comprising: a second heating unit that directly or indirectly heats the second end of the electrode body. A second electrode having a first electrode plate having a first electrode substrate and a second electrode substrate having a lower electrical resistance than the first electrode substrate, and having a potential different from that of the first electrode plate. An electrode body comprising a plate and a separator, wherein the first electrode plate and the second electrode plate are laminated via the separator,
A first current collecting member for collecting electric charges of the first electrode plate;
A secondary battery comprising: a second current collecting member that collects charges of the second electrode plate; and a battery case that accommodates the electrode body, the first current collecting member, and the second current collecting member therein. There,
The electrode body is
A laminated portion formed by laminating the first electrode plate, the second electrode plate, and the separator;
A first end portion of the first electrode plate, the second electrode plate, and the separator that protrudes from a part of the first electrode plate, the first current collecting member being A first end joined,
A second end part of the first electrode plate, the second electrode plate, and the separator that protrudes from a part of the first electrode plate, the second electrode plate, and the separator. A secondary battery having a second end joined together;
Of the outer wall portion of the battery case, when the portion close to the first end of the electrode body is the first proximity portion and the portion close to the second end is the second proximity portion, the first proximity A heating element that is fixed to at least the second proximity portion among the first proximity portion and the second proximity portion;
A first temperature sensing element that outputs a first proximity portion temperature signal corresponding to the temperature of the first proximity portion;
A second temperature sensing element that outputs a second proximity portion temperature signal corresponding to the temperature of the second proximity portion;
Control means for controlling energization to the heating element based on the first proximity part temperature signal and the second proximity part temperature signal and reducing a temperature difference between the first proximity part and the second proximity part; A secondary battery system. The secondary battery system according to claim 4,
The secondary battery is
The first electrode plate, the second electrode plate, and the separator each have a strip shape,
The electrode body is wound by laminating the strip-shaped first electrode plate, second electrode plate, and separator,
At the first end, only a part of the first electrode plate overlaps in a spiral shape,
A secondary battery system which is a secondary battery in which only a part of the second electrode plate overlaps in a spiral shape at the second end. The secondary battery system according to claim 4 or 5, wherein
As the heating element,
A first heating element fixed to the first proximity portion of the battery case;
A secondary battery system comprising: a second heating element fixed to the second proximity portion of the battery case. The secondary battery system according to any one of claims 1 to 6,
The secondary battery is
The first electrode substrate is made of aluminum;
A secondary battery system, wherein the second electrode base material is a lithium ion secondary battery made of copper.

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