JP4984456B2 - battery - Google Patents

Description

  The present invention relates to a battery including an electrode body formed by laminating a positive electrode plate and a negative electrode plate with a separator interposed therebetween.

  Conventionally, a battery including an electrode body in which a positive electrode plate and a negative electrode plate are laminated via a separator is known. In such a battery, for example, when overcharged or when heat is applied from the outside, the battery temperature rises abnormally, and depending on the use conditions, the active material of the electrode plate is thermally decomposed due to the temperature rise and gas May occur, causing a thermal runaway reaction of the battery.

  In order to solve such a problem, Patent Document 1 and Patent Document 2 propose a solution. In the battery disclosed in Patent Document 1, a low-temperature molten resin layer that melts at a temperature lower than the melting temperature of the separator in a facing surface between the outermost electrode plate of the wound electrode body and the outer case having the opposite polarity thereto. Is interposed. Alternatively, a low-temperature molten resin layer that melts at a temperature lower than the melting temperature of the separator is interposed in the facing surface between the innermost electrode plate of the wound electrode body and the member connected to the outer case of the opposite polarity. (Refer to the claim etc. of patent document 1). With such a configuration, when the battery is abnormally heated, the low-temperature molten resin layer melts, and the outermost (or innermost) electrode plate of the electrode body and the outer case (or outer case) of the opposite polarity to the electrode plate Contacted short circuit with the connected member). Then, since the short circuit current flows, the chemical reaction between the electrolytic solution and the active material is blocked, so that the battery can be prevented from causing a thermal runaway reaction.

  In addition, in the battery disclosed in Patent Document 2, the second electrode pair that is stacked via the second separator having a melting temperature lower than that of the separator and electrically connected to the positive electrode plate and the negative electrode plate is wound. It is provided on the outside of the mold electrode body (see the claims of Patent Document 2). With such a configuration, when the battery is abnormally heated, the second separator is melted and the second electrode pair is short-circuited. Then, since the short circuit current flows, the chemical reaction between the electrolytic solution and the active material is blocked, so that the battery can be prevented from causing a thermal runaway reaction.

  Alternatively, in the battery disclosed in Patent Document 2, a second electrode pair that is laminated via a second separator having a thermal contraction rate larger than that of the separator and is electrically connected to the positive electrode plate and the negative electrode plate, respectively, It is provided outside the rotary electrode body (see the claims of Patent Document 2). With such a configuration, when the battery is abnormally heated, the second separator moves due to thermal contraction, and the second electrode pair is short-circuited. Then, since the short circuit current flows, the chemical reaction between the electrolytic solution and the active material is blocked, so that the battery can be prevented from causing a thermal runaway reaction.

JP 2003-338315 A JP 2003-243037 A

  Both the battery disclosed in Patent Document 1 and the battery disclosed in Patent Document 2 are provided with a contact short-circuit mechanism separately from the electrode body for short-circuiting when the battery is abnormally heated. For this reason, the cost of a battery is caused. In addition, it is not preferable in production because it takes time to manufacture the battery.

  The present invention has been made in view of the present situation, and is a battery that can prevent thermal runaway of the battery by causing a contact short circuit when the battery is abnormally heated, while suppressing cost increase and easy manufacture. An object is to provide a battery.

The solution is a battery comprising an electrode body in which a positive electrode plate and a negative electrode plate are laminated via a separator, wherein the positive electrode plate includes a positive electrode active material presence portion having a positive electrode active material layer, and the positive electrode active material. A positive electrode active material absent portion having no material layer, and the negative electrode plate has a negative electrode active material layer, and is disposed to face the positive electrode active material present portion via the separator An active material-existing part; and a negative-electrode active material-existing part that does not have the negative-electrode active-material layer and is disposed to face the positive-electrode active-material-existing part and the separator. Is a short-circuit scheduled portion interposed between the positive electrode active material absent portion and the negative electrode active material absent portion, and melts, breaks, or moves due to heat during abnormal heat generation of the battery, Enables contact short circuit between the non-existing part and the negative active material non-existing part It has a short-circuit portion to be for revealing the shorting path that, the electrode body is wound formed by winding and laminating the elongated positive electrode plate and the elongated negative electrode plate via an elongated separator The positive electrode active material absent portion extends in the longitudinal direction of the positive electrode plate or is distributed in the form of scattered dots in the longitudinal direction, and the negative electrode active material absent portion is also in the longitudinal direction of the negative electrode plate. Or the short-circuit-scheduled portion also extends in the longitudinal direction of the separator or is distributed in the form of dots in the longitudinal direction .

  According to the present invention, at the time of abnormal heat generation of the battery, the short-circuit scheduled portion of the separator is melted, broken or moved by heat, thereby enabling contact short circuit between the positive electrode active material absent portion and the negative electrode active material absent portion. Make the short-circuit path appear. The positive electrode active material absent portion and the negative electrode active material absent portion are short-circuited due to the expansion and gasification of the electrolyte solution due to the heat generated during the abnormal heat generation and the increase in the pressure inside the battery container due to the expansion of the electrode body itself. Then, since the short circuit current flows, the chemical reaction between the electrolytic solution and the active material is blocked, so that the battery can be prevented from causing a thermal runaway reaction.

In particular, a short circuit between the positive electrode active material absent portion and the negative electrode active material absent portion has a larger resistance than a case where the positive electrode active material layer and the negative electrode active material layer are short-circuited, and thus the short circuit current is reduced. For this reason, heat generation due to the short circuit current can be suppressed, and thermal runaway of the battery caused by the heat generation can be reliably prevented. Moreover, in the present invention, so that the contact shorting during the abnormal heat generation occurs in the electrode body, the electrode body itself (positive electrode plate, negative electrode plate and a separator) so constitutes a, described in Patent Documents 1 and 2 Unlike the conventional battery, it is not necessary to provide a contact short-circuit mechanism separately from the electrode body. Therefore, the cost of the battery can be suppressed. Also, the battery is relatively easy to manufacture.
Further, in the conventional batteries described in Patent Documents 1 and 2, the contact short-circuit mechanism is provided only on the outside or part of the inside of the electrode body. For this reason, at the time of abnormal heat generation of the battery, the contact short-circuit mechanism does not function as planned, so that the contact short-circuit does not occur and the battery may run out of heat.
In contrast, in the battery of the present invention, the electrode body is a wound electrode body, and the positive electrode active material absent portion, the negative electrode active material absent portion, and the short-circuit scheduled portion each extend in the longitudinal direction or are scattered in the longitudinal direction. Distributed in dots. For this reason, since the positive electrode active material absent portion and the negative electrode active material absent portion can cause a contact short circuit in any part in the longitudinal direction, the contact short circuit between these active material absent portions is reliably performed. Therefore, it is possible to reliably prevent thermal runaway of the battery.
Another solution is a battery comprising an electrode body formed by laminating a positive electrode plate and a negative electrode plate with a separator interposed between the positive electrode plate and the positive electrode active material layer having a positive electrode active material layer, A positive electrode active material absence portion that does not have the positive electrode active material layer, and the negative electrode plate has a negative electrode active material layer and is disposed to face the positive electrode active material presence portion with the separator interposed therebetween. A negative electrode active material present part, and a negative electrode active material absent part, which does not have the negative electrode active material layer, and is disposed so as to face the positive electrode active material absent part and the separator. The separator is a short-circuit scheduled portion interposed between the positive electrode active material absent portion and the negative electrode active material absent portion, and is melted, broken, or moved by heat during abnormal heat generation of the battery, Contact short circuit between the positive electrode active material absent part and the negative electrode active material absent part A short-circuit scheduled portion that causes a short-circuit path to appear, and the short-circuit scheduled portion moves due to heat generated during abnormal heat generation of the battery, reveals the short-circuit path, and does not exist in the positive electrode active material The negative electrode active material absent portion and the short-circuit scheduled portion are batteries formed along one end side of the electrode body.
According to the present invention, at the time of abnormal heat generation of the battery, the short-circuit scheduled portion of the separator is melted, broken or moved by heat, thereby enabling contact short circuit between the positive electrode active material absent portion and the negative electrode active material absent portion. Make the short-circuit path appear. The positive electrode active material absent portion and the negative electrode active material absent portion are short-circuited due to the expansion and gasification of the electrolyte solution due to the heat generated during the abnormal heat generation and the increase in the pressure inside the battery container due to the expansion of the electrode body itself. Then, since the short circuit current flows, the chemical reaction between the electrolytic solution and the active material is blocked, so that the battery can be prevented from causing a thermal runaway reaction.
In particular, a short circuit between the positive electrode active material absent portion and the negative electrode active material absent portion has a larger resistance than a case where the positive electrode active material layer and the negative electrode active material layer are short-circuited, and thus the short circuit current is reduced. For this reason, heat generation due to the short circuit current can be suppressed, and thermal runaway of the battery caused by the heat generation can be reliably prevented. Moreover, in the present invention, the electrode body itself (positive electrode plate, negative electrode plate and separator) is configured so that a contact short circuit during abnormal heat generation occurs in the electrode body. Unlike the conventional battery, it is not necessary to provide a contact short-circuit mechanism separately from the electrode body. Therefore, the cost of the battery can be suppressed. Also, the battery is relatively easy to manufacture.
Furthermore, according to the present invention, the positive electrode active material absent portion, the negative electrode active material absent portion, and the short-circuit scheduled portion are formed along one end side of the electrode body. For this reason, when the positive electrode active material absent portion and the negative electrode active material absent portion are contact-short-circuited, heat generated by the short-circuit current is easily radiated to the outside of the electrode body. Therefore, it is possible to reliably prevent the battery from causing thermal runaway due to heat generation due to the short-circuit current.
Another solution is a battery comprising an electrode body formed by laminating a positive electrode plate and a negative electrode plate with a separator interposed between the positive electrode plate and the positive electrode active material layer having a positive electrode active material layer, A positive electrode active material absence portion that does not have the positive electrode active material layer, and the negative electrode plate has a negative electrode active material layer and is disposed to face the positive electrode active material presence portion with the separator interposed therebetween. A negative electrode active material present part, and a negative electrode active material absent part, which does not have the negative electrode active material layer, and is disposed so as to face the positive electrode active material absent part and the separator. The separator is a short-circuit scheduled portion interposed between the positive electrode active material absent portion and the negative electrode active material absent portion, and is melted, broken, or moved by heat during abnormal heat generation of the battery, Contact short circuit between the positive electrode active material absent part and the negative electrode active material absent part The electrode body is formed by laminating a long positive electrode plate and a long negative electrode plate with a long separator interposed therebetween, and winding the electrode body. The short-circuited portion is melted or broken by heat at the time of abnormal heat generation of the battery to reveal the short-circuit passage, and the positive electrode active material absent portion, the negative electrode active material The absent portion and the short-circuit scheduled portion are batteries formed in the center in the axial direction of the electrode body.
According to the present invention, at the time of abnormal heat generation of the battery, the short-circuit scheduled portion of the separator is melted, broken or moved by heat, thereby enabling contact short circuit between the positive electrode active material absent portion and the negative electrode active material absent portion. Make the short-circuit path appear. The positive electrode active material absent portion and the negative electrode active material absent portion are short-circuited due to the expansion and gasification of the electrolyte solution due to the heat generated during the abnormal heat generation and the increase in the pressure inside the battery container due to the expansion of the electrode body itself. Then, since the short circuit current flows, the chemical reaction between the electrolytic solution and the active material is blocked, so that the battery can be prevented from causing a thermal runaway reaction.
In particular, a short circuit between the positive electrode active material absent portion and the negative electrode active material absent portion has a larger resistance than a case where the positive electrode active material layer and the negative electrode active material layer are short-circuited, and thus the short circuit current is reduced. For this reason, heat generation due to the short circuit current can be suppressed, and thermal runaway of the battery caused by the heat generation can be reliably prevented. Moreover, in the present invention, the electrode body itself (positive electrode plate, negative electrode plate and separator) is configured so that a contact short circuit during abnormal heat generation occurs in the electrode body. Unlike the conventional battery, it is not necessary to provide a contact short-circuit mechanism separately from the electrode body. Therefore, the cost of the battery can be suppressed. Also, the battery is relatively easy to manufacture.
Further, when the electrode body is a wound electrode body, the temperature in the center when viewed in the axial direction is highest during overcharge. For this reason, the separator of this part melt | dissolves or heat-shrinks earliest, and a positive electrode plate and a negative electrode plate are easy to contact-short-circuit. Therefore, if the positive electrode active material existence part and the negative electrode active material existence part are located in this part, both will contact short-circuit, a big short circuit current will flow, and it will become easy to generate | occur | produce thermal runaway by the heat_generation | fever accompanying this.
On the other hand, in this invention, the positive electrode active material absence part, the negative electrode active material absence part, and the short circuit scheduled part are formed in the center of the axial direction of a wound electrode body. For this reason, during abnormal heat generation due to overcharging, the positive electrode active material absent part and the negative electrode active material absent part are present before the separator interposed between the positive electrode active material present part and the negative electrode active material present part is melted or thermally contracted. Cause a contact short circuit, so that it is possible to prevent a contact short circuit between active material existing portions. Therefore, it is possible to reliably prevent thermal runaway of the battery.
Another solution is a battery comprising an electrode body formed by laminating a positive electrode plate and a negative electrode plate with a separator interposed between the positive electrode plate and the positive electrode active material layer having a positive electrode active material layer, A positive electrode active material absence portion that does not have the positive electrode active material layer, and the negative electrode plate has a negative electrode active material layer and is disposed to face the positive electrode active material presence portion with the separator interposed therebetween. A negative electrode active material present part, and a negative electrode active material absent part, which does not have the negative electrode active material layer, and is disposed so as to face the positive electrode active material absent part and the separator. The separator is a short-circuit scheduled portion interposed between the positive electrode active material absent portion and the negative electrode active material absent portion, and is melted, broken, or moved by heat during abnormal heat generation of the battery, Contact short circuit between the positive electrode active material absent part and the negative electrode active material absent part The electrode body is a stacked electrode body in which a plurality of positive electrode plates and a plurality of negative electrode plates are alternately stacked via a separator, The short-circuit scheduled portion is melted or broken by heat at the time of abnormal heat generation of the battery to reveal the short-circuit passage, and the positive electrode active material absent portion, the negative electrode active material absent portion, and the short-circuit scheduled portion are The battery is formed in the center of a plane orthogonal to the stacking direction of the electrode bodies.
According to the present invention, at the time of abnormal heat generation of the battery, the short-circuit scheduled portion of the separator is melted, broken or moved by heat, thereby enabling contact short circuit between the positive electrode active material absent portion and the negative electrode active material absent portion. Make the short-circuit path appear. The positive electrode active material absent portion and the negative electrode active material absent portion are short-circuited due to the expansion and gasification of the electrolyte solution due to the heat generated during the abnormal heat generation and the increase in the pressure inside the battery container due to the expansion of the electrode body itself. Then, since the short circuit current flows, the chemical reaction between the electrolytic solution and the active material is blocked, so that the battery can be prevented from causing a thermal runaway reaction.
In particular, a short circuit between the positive electrode active material absent portion and the negative electrode active material absent portion has a larger resistance than a case where the positive electrode active material layer and the negative electrode active material layer are short-circuited, and thus the short circuit current is reduced. For this reason, heat generation due to the short circuit current can be suppressed, and thermal runaway of the battery caused by the heat generation can be reliably prevented. Moreover, in the present invention, the electrode body itself (positive electrode plate, negative electrode plate and separator) is configured so that a contact short circuit during abnormal heat generation occurs in the electrode body. Unlike the conventional battery, it is not necessary to provide a contact short-circuit mechanism separately from the electrode body. Therefore, the cost of the battery can be suppressed. Also, the battery is relatively easy to manufacture.
Further, when the electrode body is a multilayer electrode body, the center of the plane orthogonal to the stacking direction has the highest temperature during overcharge. For this reason, the separator of this part melt | dissolves or heat-shrinks earliest, and a positive electrode plate and a negative electrode plate are easy to contact-short-circuit. Therefore, if the positive electrode active material existence part and the negative electrode active material existence part are located in this part, both will contact short-circuit, a big short circuit current will flow, and it will become easy to generate | occur | produce thermal runaway by the heat_generation | fever accompanying this.
On the other hand, in this invention, the positive electrode active material absence part, the negative electrode active material absence part, and the short circuit scheduled part are formed in the center of the plane orthogonal to the lamination direction of a laminated electrode body. For this reason, during abnormal heat generation due to overcharging, the positive electrode active material absent part and the negative electrode active material absent part are present before the separator interposed between the positive electrode active material present part and the negative electrode active material present part is melted or thermally contracted. Cause a contact short circuit, so that it is possible to prevent a contact short circuit between active material existing portions. Therefore, it is possible to reliably prevent thermal runaway of the battery.

  Furthermore, in the battery described above, the electrode body is a wound electrode body in which a long positive electrode plate and a long negative electrode plate are stacked with a long separator interposed therebetween and wound. The positive electrode active material absent portion extends in the longitudinal direction of the positive electrode plate or is distributed in the form of dots in the longitudinal direction, and the negative electrode active material absent portion also extends in the longitudinal direction of the negative electrode plate or in the longitudinal direction. It is preferable that the battery is distributed in the form of dots and the short-circuit scheduled portion extends in the longitudinal direction of the separator or is distributed in the form of dots in the longitudinal direction.

In the conventional batteries described in Patent Documents 1 and 2, the contact short-circuit mechanism is provided only on the outside or a part of the inside of the electrode body. For this reason, at the time of abnormal heat generation of the battery, the contact short-circuit mechanism does not function as planned, so that the contact short-circuit does not occur and the battery may run out of heat.
In contrast, in the battery of the present invention, the electrode body is a wound electrode body, and the positive electrode active material absent portion, the negative electrode active material absent portion, and the short-circuit scheduled portion each extend in the longitudinal direction or are scattered in the longitudinal direction. Distributed in dots. For this reason, since the positive electrode active material absent portion and the negative electrode active material absent portion can cause a contact short circuit in any part in the longitudinal direction, the contact short circuit between these active material absent portions is reliably performed. Therefore, it is possible to reliably prevent thermal runaway of the battery.

  Furthermore, in the battery according to any one of the above, the separator has one or more first separator layers and one or more second separator layers, and the short-circuit scheduled portion is the first separator. And at least the second separator layer is interposed between the positive electrode active material existence part and the negative electrode active material existence part, and the first separator layer is formed in the short circuit scheduled part at the positive electrode active part. The second separator layer is made of a material that melts or heat shrinks at a temperature lower than a short-circuit generation temperature at which a contact short circuit occurs between the substance-free portion and the negative electrode active material-free portion, and the second separator layer has a temperature higher than the short-circuit generation temperature. Thus, it is preferable that the battery be made of a material that does not melt or heat shrink to such an extent that a contact short circuit occurs between the positive electrode active material presence portion and the negative electrode active material presence portion.

  In configuring the battery, it is sufficient to interpose one separator between the positive electrode plate and the negative electrode plate. And the part should just be made into the above-mentioned short circuit planned part. However, if the melting temperature of the separator is low or the thermal shrinkage rate is large, when the battery abnormally generates heat, before the short-circuit scheduled portion, the positive electrode active material absent portion and the negative electrode active material absent portion cause a contact short circuit. In addition, the separator interposed between the positive electrode active material existing part and the negative electrode active material existing part melts or heat shrinks, and a contact short circuit occurs between these active material existing parts, which may cause a thermal runaway. is there.

  On the other hand, in the battery of the present invention, the separator has a first separator layer that constitutes a short-circuit scheduled portion, and a second separator layer that is interposed between the positive electrode active material presence portion and the negative electrode active material presence portion. Among these, the first separator layer is made of a material that melts or heat shrinks at a temperature lower than a short-circuiting temperature at which a contact short circuit between the positive electrode active material absent portion and the negative electrode active material absent portion occurs in the short circuit scheduled portion. On the other hand, the second separator layer is made of a material that does not melt or heat shrink to such a degree that a contact short circuit between the positive electrode active material existence part and the negative electrode active material existence part occurs up to a temperature higher than the short circuit occurrence temperature. That is, the second separator layer is made of a material that does not melt or heat shrink at the temperature at which the short circuit occurs. Alternatively, it melts or heat shrinks at the expected short circuit temperature, but the degree of viscosity is such that a contact short circuit occurs between the positive electrode active material existence part and the negative electrode active material existence part due to melting or heat shrinkage of the second separator layer. It is made of a material that does not cause melting or significant heat shrinkage.

  For this reason, at the time of abnormal heat generation of the battery, the second separator layer interposed between the positive electrode active material existence part and the negative electrode active material existence part is melted or thermally contracted to cause a contact short circuit between the active material existence parts. First, the first separator layer constituting the short circuit scheduled portion is melted or thermally contracted, and the positive electrode active material absent portion and the negative electrode active material absent portion cause a contact short circuit in the short circuit planned portion. Therefore, it is possible to reliably prevent a contact short circuit between the positive electrode active material presence portion and the negative electrode active material presence portion, and it is possible to reliably prevent thermal runaway of the battery.

In the present invention, the separator only needs to have the first separator layer and the second separator layer satisfying the above requirements. For example, even if the first separator layer and the second separator layer are partially laminated, What connected the 1st separator layer and the 2nd separator layer may be used.
The first separator layer is a material that melts at a temperature lower than the short-circuiting temperature but does not shrink, or a material that heat-shrinks at a temperature lower than the short-circuiting temperature but does not melt, and is lower than the short-circuiting temperature. A material that melts and contracts at a temperature can be used. On the other hand, as described above, as the second separator layer, a material that does not substantially melt or heat shrink to a temperature higher than the short circuit occurrence temperature, that is, a material that does not melt or heat shrink, It is possible to use a material that does not melt or heat shrink to such an extent that a contact short circuit with the negative electrode active material existing portion does not occur.

  Further, in the battery according to any one of the above, the short-circuit scheduled portion is moved by heat at the time of abnormal heat generation of the battery, and the short-circuit path is exposed, and the positive electrode active material absent portion, The negative electrode active material absent portion and the short circuit scheduled portion may be a battery formed along one end side of the electrode body.

  According to the present invention, the positive electrode active material absent portion, the negative electrode active material absent portion, and the short-circuit scheduled portion are formed along one end side of the electrode body. For this reason, when the positive electrode active material absent portion and the negative electrode active material absent portion are contact-short-circuited, heat generated by the short-circuit current is easily radiated to the outside of the electrode body. Therefore, it is possible to reliably prevent the battery from causing thermal runaway due to heat generation due to the short-circuit current.

  Furthermore, in the battery according to any one of the above, the short-circuit scheduled portion is melted or broken by heat at the time of abnormal heat generation of the battery to reveal the short-circuit passage, and the positive electrode active material absent portion The negative electrode active material absent portion and the short circuit scheduled portion may be a battery formed at least in a portion of the electrode body where the temperature is highest during overcharge.

  Of the electrode body, the portion where the temperature is highest during overcharging is likely to cause contact and short circuit between the positive electrode plate and the negative electrode plate due to the separator melting and heat shrinking earlier during overcharge. However, when the positive electrode active material existence part and the negative electrode active material existence part are located at this part, both of them are contact-short-circuited, a large short-circuit current flows, and thermal runaway is likely to occur due to the heat generated thereby.

  On the other hand, in the present invention, the positive electrode active material absent portion, the negative electrode active material absent portion, and the short-circuit scheduled portion are formed at least in a portion of the electrode body where the temperature is highest during overcharge. For this reason, during abnormal heat generation due to overcharging, the positive electrode active material absent part and the negative electrode active material absent part are present before the separator interposed between the positive electrode active material present part and the negative electrode active material present part is melted or thermally contracted. Causes a contact short circuit, so that it is possible to prevent a contact short circuit between the active material existing portions. Therefore, it is possible to reliably prevent thermal runaway of the battery.

  Furthermore, in the battery according to any one of the above, the electrode body is a winding obtained by laminating a long positive electrode plate and a long negative electrode plate with a long separator interposed therebetween and winding. The short-circuit scheduled portion is melted or broken by heat at the time of abnormal heat generation of the battery to expose the short-circuit passage, and the positive electrode active material absent portion, the negative electrode active material absent portion And the said short circuit scheduled part is good to use the battery formed in the center of an axial direction among the said electrode bodies.

  When the electrode body is a wound electrode body, the temperature at the center when viewed in the axial direction is highest during overcharge. For this reason, the separator of this part melt | dissolves or heat-shrinks earliest, and a positive electrode plate and a negative electrode plate are easy to contact-short-circuit. Therefore, if the positive electrode active material existence part and the negative electrode active material existence part are located in this part, both will contact short-circuit, a big short circuit current will flow, and it will become easy to generate | occur | produce thermal runaway by the heat_generation | fever accompanying this.

  On the other hand, in this invention, the positive electrode active material absence part, the negative electrode active material absence part, and the short circuit scheduled part are formed in the center of the axial direction of a wound electrode body. For this reason, during abnormal heat generation due to overcharging, the positive electrode active material absent part and the negative electrode active material absent part are present before the separator interposed between the positive electrode active material present part and the negative electrode active material present part is melted or thermally contracted. Cause a contact short circuit, so that it is possible to prevent a contact short circuit between active material existing portions. Therefore, it is possible to reliably prevent thermal runaway of the battery.

(Embodiment 1)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a lithium secondary battery (battery) 100 according to this embodiment. The lithium secondary battery 100 is a sealed non-aqueous secondary battery used as a power source for a hybrid car or an electric vehicle. In such a lithium secondary battery 100, for example, when overcharged or when heat is applied from the outside, the battery temperature rises abnormally, and depending on the use conditions, the active material of the electrode plate is heated by the temperature rise. It decomposes and generates gas, which may cause thermal runaway reaction of the battery. Therefore, it is necessary to configure the battery so that it is possible to prevent the battery from running out of control when the battery is abnormally heated.

  The lithium secondary battery 100 is a rectangular battery having a substantially rectangular parallelepiped shape. The lithium secondary battery 100 includes a battery container 110, a safety valve 120 provided in the battery container 110, a wound electrode body 130 accommodated in the battery container 110, a positive electrode terminal 161 and a negative electrode fixed to the battery container 110, respectively. A non-aqueous electrolyte is injected into the battery case 110 and sealed.

  Specifically, the battery container 110 includes a container main body 111 that houses the wound electrode body 130 and a lid body 113 that seals the container main body 111. Both the container body 111 and the lid body 113 are made of metal. The container main body 111 has a rectangular parallelepiped shape, and has a flat plate-like rectangular bottom portion 111a and a flat plate-like rectangular shape, and four side wall portions 111b extending perpendicularly to the bottom portion 111a from the periphery of the bottom portion 111a, respectively. 111b,... On the other hand, the lid body 113 has a substantially plate shape. The container body 111 and the lid body 113 are welded over the entire circumference of the lid body 113 with the lid body 113 in contact with the side wall portions 111b, 111b,.

A safety valve 120 is provided in the approximate center of the lid 113 of the battery container 110. The safety valve 120 operates when the pressure in the battery container 110 reaches a certain level or more, and discharges the gas in the battery container 110 to the outside of the battery.
Further, a positive terminal 161 and a negative terminal 163 are fixedly provided at predetermined positions of the lid 113. The positive electrode terminal 161 is electrically connected to a positive electrode plate 131 of a wound electrode body 130, which will be described later, via a positive electrode lead 162 and the like inside the battery, while being exposed to the outside of the battery and used for electrical connection with the outside. Used. In addition, the negative electrode terminal 163 is electrically connected to a negative electrode plate 141 of a wound electrode body 130, which will be described later, via a negative electrode lead 164 or the like inside the battery, while being exposed to the outside of the battery and electrically connected to the outside. Used for connection.

  Next, the wound electrode body 130 will be described in detail (see FIGS. 2 to 4 in addition to FIG. 1). FIG. 2 shows a schematic form of the wound electrode body 130. However, the outermost part of the separator 151 is omitted. FIG. 3 shows the positional relationship in the thickness direction for each part of the positive electrode plate 131, the negative electrode plate 141, and the separator 151 constituting the wound electrode body 130. In FIG. 3, the vertical direction is the longitudinal direction of the positive electrode plate 131, the negative electrode plate 141, and the separator 151. FIG. 4 shows a part of a cross section of the wound electrode body 130.

  The wound electrode body 130 is formed by laminating a long positive electrode plate 131 and a long negative electrode plate 141 through a long separator 151 having air permeability, and this is laminated a plurality of times around an axis AX. It is comprised by winding to flat shape (refer FIG.2, FIG.4 etc.). One end (left end in FIGS. 1 to 4) of the wound electrode body 130 in the axis AX direction (left and right direction in FIGS. 2 and 4) has a positive electrode A part of the plate 131 protrudes. In addition, a part of the negative electrode plate 141 protrudes from the other end portion of the wound electrode body 130 in the axis AX direction (the right end portion in FIGS. 1 to 4) so as to be electrically connected to the negative electrode lead portion 164. ing.

  The positive electrode plate 131 has a metal foil positive electrode current collector 132 made of an aluminum foil having a thickness of 15 μm, a width of 100 mm, and a length of 8884 mm as a core material (see FIGS. 3 and 4). On the surface (both sides) of the metal foil positive electrode current collector 132 is formed a positive electrode active material layer 133 in which a positive electrode material containing a lithium cobalt composite oxide is applied along the longitudinal direction. Part 134 is configured.

  In addition, along with this, one end of the metal foil positive electrode current collector 132 in the width direction (the left end in FIGS. 3 and 4) does not have the positive electrode active material layer 133 and does not have the first positive electrode active material having a width of 15 mm. The existence part 135 is formed in a band shape in the longitudinal direction. Similarly, the second positive electrode active material having a width of 2.55 mm without the positive electrode active material layer 133 at the other end portion in the width direction of the metal foil positive electrode current collector 132 (the right end portion in FIGS. 3 and 4). The non-existing portion 136 is formed in a strip shape in the longitudinal direction.

  The negative electrode plate 141 includes, as a core material, a metal foil negative electrode current collector 142 made of a copper foil having a thickness of 10 μm, a width of 100 mm, and a length of 9102 mm (see FIGS. 3 and 4). On the surface (both sides) of the metal foil negative electrode current collector 142, a negative electrode active material layer 143 is formed by applying a negative electrode material containing carbon or the like along the longitudinal direction. It is composed. The negative electrode active material existence portion 144 is disposed to face the positive electrode active material existence portion 134 with the separator 151 interposed therebetween (see FIGS. 3 and 4).

  In addition, in accordance with this, one end portion in the width direction of the metal foil negative electrode current collector 142 (the right end portion in FIGS. 3 and 4) does not have the negative electrode active material layer 143 and has a 13 mm wide negative electrode active material absence portion. 145 is formed in a band shape in the longitudinal direction. A part of the negative electrode active material absent portion 145 is disposed so as to face the second positive electrode active material absent portion 136 via the separator 151 (see FIGS. 3 and 4).

  The separator 151 has a three-layer structure. That is, the separator 151 is made of polypropylene, and is formed of a polyethylene between the two second separator layers 153 that are porous and have air permeability. The first separator layer 152 that is porous and has air permeability. Is formed by laminating. The first separator layer 152 has a thickness of 8 μm, a width of 91 mm, and a length of 9272 mm. The second separator layer 153 has a thickness of 8 μm, a width of 87.95 mm, and a length of 9272 mm. Further, the melting temperature of the first separator layer 152 is 135 ° C., whereas the melting temperature of the second separator layer 153 is 175 ° C., which is high in heat resistance. The first separator layer 152 has a thermal contraction rate larger than that of the second separator layer 153.

  In this separator 151, a single layer portion (short-circuit planned portion) 155 located at one end portion in the width direction (right end portion in FIGS. 3 and 4) is composed of only the first separator layer 152, and has a width of 3.05 mm. It extends in the longitudinal direction. Further, in the portion of the separator 151 excluding the single layer portion 155, a multi-layer portion 156 made of the first separator layer 152 and the two second separator layers 153 and having a width of 87.95 mm and extending in the longitudinal direction is located. is doing.

  The short-circuit scheduled portion 155 of the separator 151 is interposed between the second positive electrode active material absent portion 136 and the negative electrode active material absent portion 145 (see FIGS. 3 and 4). Therefore, the second positive electrode active material absent portion 136, the negative electrode active material absent portion 145, and the short-circuit scheduled portion 155 are positioned along one end side of the wound electrode body 130. The multilayer portion 156 of the separator 151 is interposed between the positive electrode active material existence portion 134 and the negative electrode active material existence portion 144 (see FIGS. 3 and 4).

  Next, in the lithium secondary battery 100, for example, a case where the battery is overcharged or heat is applied from the outside and the battery abnormally generates heat will be described with reference to FIG. In FIG. 5, the upper diagram shows a normal state. When the battery abnormally generates heat, the heat causes thermal contraction at a temperature lower than that of the second separator layer 153, the first separator layer 152 having a large thermal contraction rate contracts, and the short-circuit scheduled portion 155 becomes the separator 151. Move toward the center in the width direction. On the other hand, the second separator layer 153 hardly moves because it hardly heat shrinks.

  Then, as shown in the center diagram in FIG. 5, a short-circuit passage 158 that enables a short-circuit between the second positive electrode active material absence portion 136 and the negative electrode active material absence portion 145 is made to appear. Further, due to the expansion and gasification of the electrolyte due to the heat during the abnormal heat generation and the increase in the pressure in the battery container 110 due to the expansion of the wound electrode body 130 itself, as shown in the lower diagram in FIG. The two positive electrode active material absence part 136 and the negative electrode active material absence part 145 are short-circuited. Then, since a short-circuit current flows here, a chemical reaction between the electrolytic solution and the active material is blocked, so that it is possible to prevent the lithium secondary battery 100 from causing a thermal runaway reaction.

  In particular, the short circuit between the second positive electrode active material absence part 136 and the negative electrode active material absence part 145 having no active material has a larger resistance than the case where the positive electrode active material layer 133 and the negative electrode active material layer 143 are short-circuited. Therefore, the short circuit current is reduced. For this reason, the heat_generation | fever by a short circuit current can be suppressed and the thermal runaway of the battery resulting from the heat_generation | fever can be prevented. In addition, in the first embodiment, the wound electrode body 130 itself is configured so that a contact short circuit in the event of abnormal heat generation occurs in the wound electrode body 130. Therefore, the electrode body as in a conventional battery is used. There is no need to provide a contact short circuit mechanism. Therefore, the cost of the lithium secondary battery 100 can be suppressed.

  Further, in the first embodiment, the electrode body is a wound electrode body 130, and the second positive electrode active material absence portion 136, the negative electrode active material absence portion 145, and the short-circuit scheduled portion 155 extend in the longitudinal direction. Yes. For this reason, since the second positive electrode active material absence part 136 and the negative electrode active material absence part 145 can cause a contact short circuit in any part in the longitudinal direction, a contact short circuit between the active material absence parts 136 and 145 is present. Is surely done. Therefore, thermal runaway of the lithium secondary battery 100 can be reliably prevented.

  In the first embodiment, the second separator layer 153 has a temperature higher than the short circuit occurrence temperature at which the contact short circuit between the second positive electrode active material absent portion 136 and the negative electrode active material absent portion 145 occurs in the short circuit planned portion 155. Until substantially no melting or heat shrinking. For this reason, when the battery is abnormally heated, the second positive electrode active material absence portion 136 and the negative electrode active material absence portion 145 are present before the positive electrode active material presence portion 134 and the negative electrode active material presence portion 144 cause a contact short circuit. Cause a contact short circuit. Therefore, it is possible to reliably prevent a contact short circuit between the positive electrode active material existence part 134 and the negative electrode active material existence part 144, and to reliably prevent thermal runaway of the lithium secondary battery 100.

  In the first embodiment, as described above, the second positive electrode active material absence portion 136, the negative electrode active material absence portion 145, and the short-circuit scheduled portion 155 are formed along one end side of the wound electrode body 130. Has been. For this reason, when the second positive electrode active material absent portion 136 and the negative electrode active material absent portion 145 are contact-short-circuited, heat generated by the short-circuit current is easily radiated to the outside of the wound electrode body 130. Therefore, it is possible to reliably prevent the lithium secondary battery 100 from causing thermal runaway due to heat generation due to the short-circuit current.

  Next, a method for manufacturing the lithium secondary battery 100 will be described. First, the positive electrode plate 131 is produced. Specifically, after applying a positive electrode paste containing a positive electrode material to a predetermined position on the surface of a metal foil positive electrode current collector 132 made of an aluminum foil, roll compression or heat treatment is performed by a known method. The positive electrode active material existence part 134 and the first and second positive electrode active material absence parts 135 and 136 described above are formed.

Further, the negative electrode plate 141 is also produced in the same manner as the positive electrode plate 131. Specifically, after applying a negative electrode paste containing a negative electrode material to a predetermined position on the surface of a metal foil negative electrode current collector 142 made of copper foil, roll compression or heat treatment is performed by a known method. The negative electrode active material existence part 144 and the negative electrode active material absence part 145 described above are formed.
In addition, the first separator layer 152 and the second separator layer 153 are aligned and laminated to produce the separator 151.

Next, the positive electrode plate 131 and the negative electrode plate 141 are aligned and stacked via the separator 151. Thereafter, these are wound into a flat shape a predetermined number of times by a known method to produce a wound electrode body 130.
On the other hand, other parts that constitute the lithium secondary battery 100 manufactured by a known method are prepared. Then, the lithium secondary battery 100 is assembled by a known method using the wound electrode body 130 and other components. Thus, the lithium secondary battery 100 is completed. As described above, in the first embodiment, since there is no contact short-circuit mechanism formed separately from the conventional electrode body, it is relatively easy to manufacture the lithium secondary battery 100.

(Example)
In order to verify the effect of the present invention, the lithium secondary battery 100 according to Embodiment 1 was prepared as an example. In addition, as a comparative example, a lithium secondary battery having a conventional wound electrode body configured with a positive electrode plate, a negative electrode plate, and a separator was also prepared so as not to cause a contact short circuit between the active material absent portions during abnormal heat generation. . And the electric current was sent through these samples, it was set as the overcharge state, and the state of the lithium secondary battery 100 grade | etc., Was observed. The results are shown in Table 1.

  In Table 1, “open valve” means that the safety valve 120 provided in the battery container 110 is opened. “Mist” means that the electrolyte gasified and was blown out from the safety valve 120. In addition, “smoke” means that the lithium secondary battery caused a thermal runaway and smoke was seen in the lithium secondary battery.

  As is clear from Table 1, in the example, no thermal runaway reaction occurred even in a large current region where heat generation was larger, such as 26 A or 50 A, and no smoke was observed in the lithium secondary battery 100. On the other hand, in the comparative example, when a large current of 13 A or more was passed, a thermal runaway reaction occurred, and smoke was seen in the lithium secondary battery 100. Moreover, the temperature of the battery surface also became abnormally high. From this, it can be said that the lithium secondary battery 100 of the first embodiment can prevent the battery from being runaway by causing a contact short circuit when abnormal heat is generated.

(Embodiment 2)
Next, a second embodiment will be described. Note that the description of the same parts as those in the first embodiment is omitted or simplified. The lithium secondary battery 200 of the second embodiment is different from the wound electrode body 130 of the first embodiment in the structure of the wound electrode body 230. The other configuration is the same (see FIG. 1). 6 to 8 show a wound electrode body 230 according to the second embodiment. FIG. 6 shows a schematic form of the wound electrode body 230. However, the outermost part of the separator 251 is omitted. FIG. 7 shows the positional relationship in the thickness direction for each part of the positive electrode plate 231, the negative electrode plate 241 and the separator 251 constituting the wound electrode body 230. FIG. 8 shows a part of a cross section of the wound electrode body 230.

  In the wound electrode body 230 according to the second embodiment, a long positive electrode plate 231 and a long negative electrode plate 241 are stacked via a long separator 251 having air permeability, and a plurality of these are stacked. It is constituted by winding around the axis AX in a flat shape (see FIGS. 6 and 8). A part of the positive electrode plate 231 protrudes at one end of the wound electrode body 230 in the axis AX direction (left and right direction in FIGS. 6, 8, etc.) in order to be electrically connected to the positive electrode lead 162 ( (See FIGS. 1, 6 and 8). In addition, a part of the negative electrode plate 241 protrudes from the other end portion in the axial direction of the wound electrode body 230 in order to be electrically connected to the negative electrode lead portion 164 (FIGS. 1, 6, and 8). Etc.).

  The positive electrode plate 231 has an aluminum metal foil positive electrode current collector 232 having a thickness of 15 μm, a width of 100 mm, and a length of 8884 mm as a core material (see FIGS. 7 and 8). On the surface (both sides) of the metal foil positive electrode current collector 232, a positive electrode active material layer 233 is formed by coating the positive electrode material along the longitudinal direction, and a positive electrode active material existence portion 234 that forms two strips is formed. is doing.

  Accordingly, one end of the metal foil positive electrode current collector 232 in the width direction (the left end in FIGS. 7 and 8) does not have the positive electrode active material layer 233 and does not have the first positive electrode active material having a width of 15 mm. The existence part 235 is formed in a band shape in the longitudinal direction. Similarly, in the metal foil positive electrode current collector 232, the second positive electrode active material absence portion having a width of 10 mm that does not include the positive electrode active material layer 233 between the two positive electrode active material existence portions 234 having a band shape. 236 is formed in a band shape in the longitudinal direction.

  The negative electrode plate 241 has a metal foil negative electrode current collector 242 having a thickness of 10 μm, a width of 100 mm, and a length of 9102 mm as a core material (see FIGS. 7 and 8). On the surface (both sides) of the metal foil negative electrode current collector 242, a negative electrode active material layer 243 obtained by coating the negative electrode material along the longitudinal direction is formed, and a negative electrode active material existence portion 244 having two strips is formed. is doing. These negative electrode active material existence portions 244 are arranged to face the positive electrode active material existence portion 234 with the separator 251 therebetween (see FIG. 8 and the like).

  In addition, along with this, one end portion in the width direction of the metal foil negative electrode current collector 242 (the right end portion in FIGS. 7 and 8) does not have the negative electrode active material layer 243 and does not have the first negative electrode active material having a width of 13 mm. The existence portion 245 is formed in a strip shape in the longitudinal direction. Similarly, in the metal foil negative electrode current collector 242, a second negative electrode active material absence portion having a width of 10 mm that does not include the negative electrode active material layer 243 between the two negative electrode active material existence portions 244 having a strip shape. 246 is formed in a band shape in the longitudinal direction. The second negative electrode active material absent portion 246 is disposed to face the second positive electrode active material absent portion 236 with the separator 251 interposed therebetween (see FIG. 8 and the like).

  The separator 251 has a three-layer structure. That is, one first separator layer 252 made of polyethylene, porous, and air permeable is laminated between two second separator layers 253 made of polypropylene and having air permeability. It is constituted by. The first separator layer 252 has a thickness of 8 μm, a width of 91 mm, and a length of 9272 mm. The second separator layer 253 is divided into two along the longitudinal direction, and each dimension is 8 μm in thickness, 91 mm in width, and 9272 mm in length. Further, the melting temperature of the first separator layer 252 is 135 ° C., whereas the melting temperature of the second separator layer 253 is 175 ° C., which is high in heat resistance. The first separator layer 252 has a thermal contraction rate larger than that of the second separator layer 253.

  In this separator 251, a single layer portion (short-circuit scheduled portion) 255 located at the center in the width direction is composed of only the first separator layer 252 and extends in the longitudinal direction with a width of 6 mm. Of the separator 251, two multilayer portions 256 located on both sides of the single layer portion 255 are composed of a first separator layer 252 and two second separator layers 253, each having a width of 42.5 mm and a longitudinal direction. It extends to.

  The short-circuit scheduled portion 255 of the separator 251 is interposed between the second positive electrode active material absent portion 236 and the second negative electrode active material absent portion 246 (see FIGS. 7 and 8). Therefore, the second positive electrode active material absent portion 236, the second negative electrode active material absent portion 246, and the short circuit scheduled portion 255 are located at the center of the wound electrode body 230 in the axis AX direction. Moreover, the multilayer part 256 of the separator 251 is interposed between the positive electrode active material existence part 234 and the negative electrode active material existence part 244, respectively (see FIGS. 7 and 8).

  Next, in the lithium secondary battery 200, a case where the battery abnormally generates heat will be described with reference to FIG. In FIG. 9, the upper diagram shows a normal state. When the battery abnormally generates heat, the heat causes the first separator layer 252 having a large thermal contraction rate and low heat resistance to shrink, and to melt at the short-circuit scheduled portion 255. On the other hand, at this temperature, the second separator layer 253 hardly melts or heat shrinks, so that the second separator layer 253 does not melt or move greatly.

  Then, as shown in the center diagram in FIG. 9, a short-circuit passage 258 that enables a short-circuit between the second positive electrode active material absent portion 236 and the second negative electrode active material absent portion 246 is made to appear. Furthermore, due to the expansion and gasification of the electrolyte due to the heat during the abnormal heat generation and the increase in the pressure in the battery container 110 due to the expansion of the wound electrode body 230 itself, as shown in the lower diagram in FIG. The two positive electrode active material absence part 236 and the second negative electrode active material absence part 246 are short-circuited. Then, since the short circuit current flows, the chemical reaction between the electrolytic solution and the active material is blocked, so that it is possible to prevent the lithium secondary battery 200 from causing a thermal runaway reaction.

  Also in the second embodiment, the wound electrode body 230 itself is configured so that a contact short circuit in the event of abnormal heat generation occurs in the wound electrode body 230, so that it is separate from the electrode body as in a conventional battery. There is no need to provide a contact short-circuit mechanism. Therefore, the cost of the lithium secondary battery 200 can be suppressed. Moreover, the manufacture of the lithium secondary battery 200 is relatively easy.

  Furthermore, in the second embodiment, the second positive electrode active material absence part 236, the second negative electrode active material are provided at the center in the axis AX direction of the wound electrode body 230, which is the part where the temperature becomes highest during overcharge. A non-existing portion 246 and a short-circuit scheduled portion 255 are formed. For this reason, at the time of abnormal heat generation due to overcharge, the second portion before the separator 251 (multi-layer portion 256) is melted or thermally contracted at the portion interposed between the positive electrode active material presence portion 234 and the negative electrode active material presence portion 244. Since the positive electrode active material absence part 236 and the second negative electrode active material absence part 246 cause a contact short circuit, it is possible to reliably prevent a contact short circuit between the active material existence parts 234 and 244. Therefore, thermal runaway of the lithium secondary battery 200 can be reliably prevented. In addition, the same parts as those of the first embodiment have the same effects. Note that the lithium secondary battery 200 according to the second embodiment may be manufactured basically in the same manner as the lithium secondary battery 100 according to the first embodiment.

(Embodiment 3)
Next, a third embodiment will be described. Note that description of the same parts as those in the first or second embodiment is omitted or simplified. The lithium secondary battery 300 according to the third embodiment is greatly different from the first and second embodiments in which the electrode body is a laminated electrode body 330 and the electrode bodies are wound electrode bodies 130 and 230. Other configurations are substantially the same (see FIG. 1). 10 to 12 show a stacked electrode body 330 according to the third embodiment. FIG. 10 shows a schematic form of the laminated electrode body 330. However, the separator 351 located on the outermost surface is omitted. FIG. 11 shows the positional relationship in the thickness direction for each part of the positive electrode plate 331, the negative electrode plate 341, and the separator 351 constituting the laminated electrode body 330. FIG. 12 shows a part of a cross section of the laminated electrode body 330.

  The laminated electrode body 330 according to the third embodiment is obtained by alternately laminating a plurality of rectangular positive plates 331 and a plurality of rectangular negative plates 341 via a rectangular separator 351 having air permeability. It is configured (see FIG. 10, FIG. 12, etc.). A part of the positive electrode plate 331 is connected to one end portion (the left end portion in FIGS. 10, 12, etc.) of the stacked electrode body 330 in order to be electrically connected to the positive electrode lead 162 through a positive electrode current collector plate (not shown). Protrudes (see FIGS. 1, 10, 12, etc.). In addition, in order to be electrically connected to the negative electrode lead portion 164 through a negative electrode current collector plate (not shown) at one end (the right end in FIGS. 10 and 12) on the opposite side of the multilayer electrode body 330, A part of the negative electrode plate 341 protrudes (see FIGS. 1, 10, 12, etc.).

  The positive electrode plate 331 has a metal foil positive electrode current collector 332 having a thickness of 15 μm, a width of 100 mm, and a length of 80 mm as a core material (see FIGS. 11 and 12, etc.). On the surface (both sides) of the metal foil positive electrode current collector 332, a positive electrode active material layer 333 coated with a positive electrode material is formed to constitute a positive electrode active material existence portion 334 that forms two strips.

  Accordingly, one end of the metal foil positive electrode current collector 332 (the left end in FIGS. 11 and 12) does not have the positive electrode active material layer 333, and the first positive electrode active material absent portion 335 having a width of 15 mm. Is formed in a band shape. Similarly, in the metal foil positive electrode current collector 332, the second positive electrode active material absence portion having a width of 10 mm that does not include the positive electrode active material layer 333 between the two positive electrode active material existence portions 334 formed in a strip shape. 336 is formed in a strip shape.

  The negative electrode plate 341 includes a metal foil negative electrode current collector 342 having a thickness of 10 μm, a width of 100 mm, and a length of 80 mm as a core material (see FIGS. 11 and 12, etc.). On the surface (both sides) of the metal foil negative electrode current collector 342, a negative electrode active material layer 343 coated with a negative electrode material is formed to constitute a negative electrode active material existence portion 344 having two strips. These negative electrode active material existence portions 344 are arranged to face the positive electrode active material existence portion 334 with the separator 351 therebetween (see FIG. 12 and the like).

  Accordingly, one end of the metal foil negative electrode current collector 342 (the right end in FIGS. 11 and 12) does not have the negative electrode active material layer 343, and the first negative electrode active material absent portion 345 having a width of 13 mm. Is formed in a band shape. Similarly, in the metal foil negative electrode current collector 342, the second negative electrode active material absence portion having a width of 10 mm that does not include the negative electrode active material layer 343 between the two negative electrode active material existence portions 344 having a strip shape. 346 is formed in a strip shape. The second negative electrode active material absence portion 346 is disposed to face the second positive electrode active material absence portion 336 with the separator 351 therebetween (see FIG. 12 and the like).

  The separator 351 has a three-layer structure. That is, one first separator layer 352 made of polyethylene, porous and air permeable is laminated between two second separator layers 353 made of polypropylene and having air permeability. It is constituted by. The first separator layer 352 has a thickness of 8 μm, a width of 91 mm, and a length of 86 mm. The second separator layer 353 is divided into two parts, each having a thickness of 8 μm, a width of 91 mm, and a length of 86 mm. Further, the melting temperature of the first separator layer 352 is 135 ° C., whereas the melting temperature of the second separator layer 353 is 175 ° C., which is high in heat resistance. The first separator layer 352 has a thermal contraction rate larger than that of the second separator layer 353.

  In this separator 351, a single layer portion (short-circuit scheduled portion) 355 located at the center in the width direction (lateral direction in the figure) is composed of only the first separator layer 352, and extends in the vertical direction with a width of 6 mm. Of the separator 351, two multilayer portions 356 located on both sides of the single layer portion 355 are composed of a first separator layer 352 and two second separator layers 353, each having a width of 42.5 mm and a longitudinal direction. It extends to.

  The short circuit scheduled portion 355 of the separator 351 is interposed between the second positive electrode active material absent portion 336 and the second negative electrode active material absent portion 346 (see FIGS. 11 and 12). Accordingly, the second positive electrode active material absent portion 336, the second negative electrode active material absent portion 346, and the short circuit scheduled portion 355 include a center of a plane perpendicular to the stacking direction of the wound electrode body 330. It is formed in a band shape. Moreover, the multilayer part 356 of the separator 351 is interposed between the positive electrode active material existence part 334 and the negative electrode active material existence part 344, respectively (see FIGS. 11 and 12).

  Next, in the lithium secondary battery 300, the case where the battery abnormally generates heat will be described with reference to FIG. In FIG. 13, the upper diagram shows the normal time. When the battery abnormally generates heat, the heat causes the first separator layer 352 having a large heat shrinkage ratio and low heat resistance to shrink, and at the short-circuit scheduled portion 355, the battery is blown out. On the other hand, at this temperature, the second separator layer 353 hardly melts or heat shrinks, so the second separator layer 353 does not melt or move significantly.

  Then, as shown in the center diagram in FIG. 13, a short-circuit passage 358 that enables a short-circuit between the second positive electrode active material absence portion 336 and the second negative electrode active material absence portion 346 is made to appear. Further, due to the expansion and gasification of the electrolyte solution due to the heat during the abnormal heat generation, and the increase in the pressure inside the battery container 110 due to the expansion of the multilayer electrode body 330 itself, as shown in the lower diagram in FIG. The positive electrode active material absent portion 336 and the second negative electrode active material absent portion 346 are short-circuited. Then, since the short-circuit current flows, the chemical reaction between the electrolytic solution and the active material is blocked, so that the lithium secondary battery 300 can be prevented from causing a thermal runaway reaction.

  Also in the third embodiment, since the stacked electrode body 330 itself is configured so that a contact short circuit during abnormal heat generation occurs in the stacked electrode body 330, a contact short circuit separate from the electrode body as in the conventional battery. There is no need to provide a mechanism. Therefore, the cost of the lithium secondary battery 300 can be suppressed. Moreover, the manufacture of the lithium secondary battery 300 is relatively easy.

  Furthermore, in the third embodiment, the second positive electrode active material absent portion 336 includes a center of a plane orthogonal to the stacking direction of the stacked electrode body 330, which is a portion where the temperature becomes highest during overcharge. A second negative electrode active material absent portion 346 and a short-circuit scheduled portion 355 are formed. For this reason, during abnormal heat generation due to overcharging, the second positive electrode active portion 334 (multilayer portion 356) interposed between the positive electrode active material presence portion 334 and the negative electrode active material presence portion 344 is blown out or thermally contracted. Since the material absent portion 336 and the second negative electrode active material absent portion 346 cause a contact short circuit, it is possible to prevent a contact short circuit between the active material presence portions 334 and 344. Therefore, thermal runaway of the lithium secondary battery 300 can be reliably prevented. In addition, the same parts as in the first or second embodiment have the same effects. Note that the lithium secondary battery 300 according to the third embodiment may be manufactured basically in the same manner as the lithium secondary battery 100 according to the first embodiment.

In the above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to the above-described first to third embodiments, and can be appropriately modified and applied without departing from the gist thereof. Not too long.
For example, in the first embodiment, the case where the short-circuit scheduled portion 155 of the separator 151 is moved by heat and the short-circuit passage 158 appears is shown. Moreover, in the said Embodiment 2, 3, the short circuit scheduled part 255,355 of the separators 251 and 351 showed the case where it melt | dissolves with heat and moves, and the short circuit paths 258 and 358 appear. However, the method of appearing the short circuit passage is not limited to these. For example, a perforation may be provided in the short-circuit scheduled portion of the separator, and it may be broken by heat so that the short-circuit path appears.

In the first and second embodiments, the short circuit planned portions 155 and 255 are formed extending in the longitudinal direction. However, the short circuit planned portions and the like may be distributed in the form of dots in the longitudinal direction. .
In the first to third embodiments, the second separator layers 153, 253, and 353 of the separators 151, 251 and 351 are made of polypropylene having high heat resistance and low heat shrinkage. Alternatively, it may be made of a material that does not melt even at high temperatures and does not heat shrink.

  In the first to third embodiments, the thermal contraction rate of the first separator layers 152, 252, and 352 is increased, while the thermal contraction rate of the second separator layers 153, 253, and 353 is decreased. However, if the temperature causing the thermal contraction of the first separator layer 152 or the like is lowered while the temperature causing the thermal contraction of the second separator layer 153 or the like is increased, the second separator layer 153 or the like is made of a material having a large thermal contraction rate. Can also be used.

1 is an explanatory diagram showing a schematic form of a lithium secondary battery according to Embodiment 1. FIG. 3 is an explanatory diagram showing a schematic form of a wound electrode body of a lithium secondary battery according to Embodiment 1. FIG. FIG. 3 is an explanatory diagram showing a positional relationship in a thickness direction of each part of a positive electrode plate, a negative electrode plate, and a separator in a wound electrode body of a lithium secondary battery according to Embodiment 1. FIG. 3 is an explanatory diagram showing a partial cross section of a wound electrode body in the lithium secondary battery according to Embodiment 1. It is explanatory drawing which shows the effect | action which a contact short circuit produces about the lithium secondary battery which concerns on Embodiment 1. FIG. 6 is an explanatory view showing a schematic form of a wound electrode body of a lithium secondary battery according to Embodiment 2. FIG. It is explanatory drawing which shows the positional relationship of the thickness direction of each part of a positive electrode plate, a negative electrode plate, and a separator among the winding type electrode bodies of the lithium secondary battery which concerns on Embodiment 2. FIG. FIG. 6 is an explanatory diagram showing a partial cross section of a wound electrode body in a lithium secondary battery according to Embodiment 2. It is explanatory drawing which shows the effect | action which a contact short circuit produces about the lithium secondary battery which concerns on Embodiment 2. FIG. 6 is an explanatory view showing a schematic form of a wound electrode body of a lithium secondary battery according to Embodiment 3. FIG. It is explanatory drawing which shows the positional relationship of the thickness direction of each part of a positive electrode plate, a negative electrode plate, and a separator among the winding type electrode bodies of the lithium secondary battery which concerns on Embodiment 3. FIG. FIG. 4 is an explanatory diagram showing a partial cross section of a wound electrode body in a lithium secondary battery according to Embodiment 3. It is explanatory drawing which shows the effect | action which a contact short circuit produces about the lithium secondary battery which concerns on Embodiment 3. FIG.

100, 200, 300 Lithium secondary battery (battery)
130,230 Winding type electrode body (electrode body)
330 Stacked electrode body (electrode body)
131, 231, 331 Cathode plates 133, 233, 333 Cathode active material layer 134, 234, 334 Cathode active material present part 135, 235 First cathode active material absent part 136, 236 Second cathode active material absent part 141, 241, 341 Negative electrode plate 143, 243, 343 Negative electrode active material layer 144, 244, 344 Negative electrode active material existence part 145 Negative electrode active material absence part 245, 345 First negative electrode active material absence part 246, 346 Second negative electrode active material Absent portions 151, 251, 351 Separator 152, 252, 352 First separator layer 153, 253, 353 Second separator layer 155, 255, 355 Single layer portion (scheduled short-circuit portion)
156, 256, 356 Multi-layer part

Claims (10)

A battery comprising an electrode body formed by laminating a positive electrode plate and a negative electrode plate via a separator,
The positive electrode plate is
A positive electrode active material presence part having a positive electrode active material layer;
A positive electrode active material absent portion not having the positive electrode active material layer,
The negative electrode plate is
A negative electrode active material layer, having a negative electrode active material layer, the negative electrode active material layer being disposed opposite to the positive electrode active material layer;
Having no negative electrode active material layer, having a negative electrode active material absence portion formed by facing the positive electrode active material absence portion and the separator,
The separator is
A short-circuit scheduled portion interposed between the positive electrode active material non-existing portion and the negative electrode active material non-existing portion, which melts, breaks, or moves due to heat during abnormal heat generation of the battery, thereby revealing the shorting path to allow the a missing portion contacting short-circuit between the negative electrode active material missing portion have a short portion to be,
The electrode body is a wound electrode body formed by laminating and winding a long positive electrode plate and a long negative electrode plate through a long separator,
The positive electrode active material absent portion extends in the longitudinal direction of the positive electrode plate or is distributed in the form of dots in the longitudinal direction,
The negative electrode active material absent portion also extends in the longitudinal direction of the negative electrode plate or is distributed in the form of dots in the longitudinal direction,
The battery is also provided with the short-circuited portions extending in the longitudinal direction of the separator or distributed in the form of dots in the longitudinal direction . A battery comprising an electrode body formed by laminating a positive electrode plate and a negative electrode plate via a separator,
The positive electrode plate is
A positive electrode active material presence part having a positive electrode active material layer;
A positive electrode active material absent portion not having the positive electrode active material layer,
The negative electrode plate is
A negative electrode active material layer, having a negative electrode active material layer, the negative electrode active material layer being disposed opposite to the positive electrode active material layer;
Having no negative electrode active material layer, having a negative electrode active material absence portion formed by facing the positive electrode active material absence portion and the separator,
The separator is
A short-circuit scheduled portion interposed between the positive electrode active material non-existing portion and the negative electrode active material non-existing portion, which melts, breaks, or moves due to heat during abnormal heat generation of the battery, thereby revealing the shorting path to allow the a missing portion contacting short-circuit between the negative electrode active material missing portion have a short portion to be,
The short-circuit scheduled portion is moved by heat at the time of abnormal heat generation of the battery, and the short-circuit path is exposed,
The battery, wherein the positive electrode active material absent portion, the negative electrode active material absent portion, and the short-circuit scheduled portion are formed along one end side of the electrode body . A battery comprising an electrode body formed by laminating a positive electrode plate and a negative electrode plate via a separator,
The positive electrode plate is
A positive electrode active material presence part having a positive electrode active material layer;
A positive electrode active material absent portion not having the positive electrode active material layer,
The negative electrode plate is
A negative electrode active material layer, having a negative electrode active material layer, the negative electrode active material layer being disposed opposite to the positive electrode active material layer;
Having no negative electrode active material layer, having a negative electrode active material absence portion formed by facing the positive electrode active material absence portion and the separator,
The separator is
A short-circuit scheduled portion interposed between the positive electrode active material non-existing portion and the negative electrode active material non-existing portion, which melts, breaks, or moves due to heat during abnormal heat generation of the battery, thereby revealing the shorting path to allow the a missing portion contacting short-circuit between the negative electrode active material missing portion have a short portion to be,
The electrode body is a wound electrode body formed by laminating and winding a long positive electrode plate and a long negative electrode plate through a long separator,
The short-circuit scheduled portion is melted or broken by heat at the time of abnormal heat generation of the battery, and the short-circuit path is exposed,
The battery, wherein the positive electrode active material absent portion, the negative electrode active material absent portion, and the short-circuit scheduled portion are formed at the center in the axial direction of the electrode body . A battery comprising an electrode body formed by laminating a positive electrode plate and a negative electrode plate via a separator,
The positive electrode plate is
A positive electrode active material presence part having a positive electrode active material layer;
A positive electrode active material absence portion that does not have the positive electrode active material layer,
The negative electrode plate is
A negative electrode active material layer, having a negative electrode active material layer, the negative electrode active material layer being disposed opposite to the positive electrode active material layer;
Having no negative electrode active material layer, having a negative electrode active material absence portion formed by facing the positive electrode active material absence portion and the separator,
The separator is
A short-circuit scheduled portion interposed between the positive electrode active material non-existing portion and the negative electrode active material non-existing portion, which melts, breaks, or moves due to heat during abnormal heat generation of the battery, thereby revealing the shorting path to allow the a missing portion contacting short-circuit between the negative electrode active material missing portion have a short portion to be,
The electrode body is a laminated electrode body in which a plurality of positive electrode plates and a plurality of negative electrode plates are alternately laminated via separators,
The short-circuit scheduled portion is melted or broken by heat at the time of abnormal heat generation of the battery, and the short-circuit path is exposed,
The battery, wherein the positive electrode active material absent portion, the negative electrode active material absent portion, and the short-circuit scheduled portion are formed in the center of a plane perpendicular to the stacking direction of the electrode body . The battery according to claim 2 or claim 3 ,
The electrode body is a wound electrode body formed by laminating and winding a long positive electrode plate and a long negative electrode plate through a long separator,
The positive electrode active material absent portion extends in the longitudinal direction of the positive electrode plate or is distributed in the form of dots in the longitudinal direction,
The negative electrode active material absent portion also extends in the longitudinal direction of the negative electrode plate or is distributed in the form of dots in the longitudinal direction,
The battery in which the short-circuit-scheduled portions also extend in the longitudinal direction of the separator or are distributed in the longitudinal direction. A battery according to any one of claims 2 to 5 ,
The separator has one or more first separator layers and one or more second separator layers,
The short-circuit scheduled portion is composed of the first separator layer,
At least the second separator layer is interposed between the positive electrode active material existence part and the negative electrode active material existence part,
The first separator layer is made of a material that melts or heat shrinks at a temperature lower than a short circuit generation temperature at which a contact short circuit occurs between the positive electrode active material absence part and the negative electrode active material absence part in the short circuit scheduled part,
The second separator layer is a battery made of a material that does not melt or heat shrink to such a degree that a contact short circuit between the positive electrode active material existence part and the negative electrode active material existence part occurs up to a temperature higher than the short circuit occurrence temperature. The battery according to claim 1 ,
The separator has one or more first separator layers and one or more second separator layers,
The short-circuit scheduled portion is composed of the first separator layer,
At least the second separator layer is interposed between the positive electrode active material existence part and the negative electrode active material existence part,
The first separator layer is made of a material that melts or heat shrinks at a temperature lower than a short circuit generation temperature at which a contact short circuit occurs between the positive electrode active material absence part and the negative electrode active material absence part in the short circuit scheduled part,
The second separator layer is a battery made of a material that does not melt or heat shrink to such a degree that a contact short circuit between the positive electrode active material existence part and the negative electrode active material existence part occurs up to a temperature higher than the short circuit occurrence temperature. The battery according to claim 1 or 7 ,
The short-circuit scheduled portion is moved by heat at the time of abnormal heat generation of the battery, and the short-circuit path is exposed,
The positive electrode active material absent portion, the negative electrode active material absent portion, and the short circuit scheduled portion are formed along one end side of the electrode body. The battery according to claim 1 or 7 ,
The short-circuit scheduled portion is melted or broken by heat at the time of abnormal heat generation of the battery, and the short-circuit path is exposed,
The positive electrode active material absent portion, the negative electrode active material absent portion, and the short-circuit scheduled portion are formed in a portion of the electrode body that has the highest temperature during at least overcharge. The battery according to claim 1 or 7 ,
Before Symbol short scheduled portion is blown or broken by heat during abnormal heat generation of the battery, to appear the shorting path,
The positive electrode active material absent portion, the negative electrode active material absent portion, and the short-circuit scheduled portion are formed in the center of the electrode body in the axial direction.

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