Battery

Abstract

To provide a battery in which ejected matter from inside a casing is prevented from ejecting in an unintended direction. The battery includes an electrode assembly and a housing having a first flat surface and housing the electrode assembly. The first surface of the housing is provided with a first exhaust valve that opens when a first internal pressure acts on the battery, and a second exhaust valve that opens when a second internal pressure higher than the first internal pressure acts on the battery.

Description

[Technical Field]

[0001] The present technology relates to batteries. [Background technology]

[0002] Batteries that are provided with a gas exhaust valve that opens when the internal pressure of the housing that houses the electrode assembly exceeds a predetermined value, thereby discharging gas inside the housing to the outside, are conventionally known.

[0003] Examples of conventional batteries include those described in Japanese Patent Laid-Open No. 2002-033091 (Patent Document 1), Japanese Patent Laid-Open No. 2002-063888 (Patent Document 2), and Japanese Patent Laid-Open No. 2001-307705 (Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-033091 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-063888 [Patent Document 3] Japanese Patent Application Laid-Open No. 2001-307705 Summary of the Invention [Problem to be solved by the invention]

[0005] In a battery pack consisting of multiple batteries, when gas is released from one battery, it is necessary to prevent it from unintentionally affecting adjacent batteries. Therefore, it is necessary to prevent material ejected from inside the casing from being ejected in an unintended direction. From the above perspective, there is still room for improvement in conventional batteries.

[0006] An object of the present technology is to provide a battery that prevents ejection of material from inside the casing in unintended directions. [Means for solving the problem]

[0007] The present technology provides the following batteries:

[0008] [1] A battery comprising an electrode body and a housing having a first surface made of a flat surface and housing the electrode body, wherein a first exhaust valve that opens when a first internal pressure acts on the battery and a second exhaust valve that opens when a second internal pressure higher than the first internal pressure acts on the battery are provided on the first surface of the housing.

[0009] [2] The battery according to [1], wherein the second internal pressure is 1.1 times or more the first internal pressure.

[0010] [3] The battery according to [1] or [2], wherein the second exhaust valve is provided to encompass the first exhaust valve.

[0011] [4] The battery according to [1] or [2], wherein the second exhaust valve is provided so as to be spaced apart from the first exhaust valve.

[0012] [5] The battery according to any one of [1] to [4], wherein the first exhaust valve and the second exhaust valve are formed by grooves or thin-walled portions provided on the first surface of the housing.

[0013] [6] The battery according to any one of [1] to [5], wherein the housing has a rectangular shape. [Effects of the Invention]

[0014] According to the present technology, it is possible to provide a battery in which ejected material from inside the housing is prevented from ejecting in unintended directions. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a perspective view showing a battery pack. [Figure 2] FIG. [Figure 3] FIG. 2 is a perspective view showing a sealing plate and an electrode terminal. [Figure 4]FIG. 10 is a diagram showing a state in which the electrode terminal and the electrode body are electrically connected. [Figure 5] FIG. 1 is a diagram (part 1) showing the arrangement of gas release valves provided on a sealing plate. [Figure 6] FIG. 2 is a diagram (part 2) showing the arrangement of gas release valves provided on the sealing plate. [Figure 7] FIG. 3 is a diagram (part 3) showing the arrangement of gas release valves provided on the sealing plate. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof may not be repeated.

[0017] In the embodiments described below, when numbers, amounts, etc. are mentioned, the scope of the present technology is not necessarily limited to those numbers, amounts, etc., unless otherwise specified. Furthermore, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. Furthermore, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiments.

[0018] In this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a certain feature is included, other features may or may not be included.

[0019] Furthermore, when geometric terms and terms expressing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along," these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in a single state, and the relative positional relationships can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0020] In this specification, the term "battery" is not limited to lithium-ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, the term "electrode" may collectively refer to a positive electrode and a negative electrode.

[0021] In this specification, a "battery" can be installed in a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an electric vehicle (BEV), etc. However, the use of a "battery" is not limited to being installed in a vehicle.

[0022] Fig. 1 is a perspective view showing a battery pack. As shown in Fig. 1, the battery pack 1 includes batteries 100, separators 200, and end plates 300. The batteries 100 and separators 200 are arranged alternately along the Y-axis direction (first direction). The end plates 300 are provided at both ends in the Y-axis direction.

[0023] The batteries 100 are rectangular batteries, and a plurality of batteries 100 are provided along the Y-axis direction. The plurality of batteries 100 are electrically connected to each other via bus bars (not shown).

[0024] Separators 200 are provided between multiple batteries 100. The separators 200 are insulating members that prevent unintended electrical conduction between adjacent batteries 100. The separators 200 ensure electrical insulation between adjacent batteries 100. Separators 200 are also provided between the batteries 100 and the end plates 300.

[0025] The end plates 300 provided at both ends in the Y-axis direction are connected to each other by a restraining member (not shown). At this time, the stack of multiple batteries 100 and separators 200 is held in a compressed state in the Y-axis direction by the end plates 300. As a reaction, a reaction force from the batteries 100 acts on the end plates 300, and a tensile stress in the Y-axis direction is generated in the restraining member.

[0026] 2 is a perspective view showing the battery 100. As shown in Fig. 2, the battery 100 has a rectangular shape. The battery 100 has an electrode terminal 110, a housing 120, a gas release valve 130, and a liquid injection hole 140.

[0027] The electrode terminal 110 is formed on the housing 120. The electrode terminal 110 has a positive electrode terminal 111 and a negative electrode terminal 112 that are aligned along the X-axis direction (second direction) that is perpendicular to the Y-axis direction. The positive electrode terminal 111 and the negative electrode terminal 112 are spaced apart from each other in the X-axis direction.

[0028] The housing 120 has a rectangular parallelepiped shape and forms the external appearance of the battery 100. The housing 120 includes a case body 120A that contains electrode assemblies (for example, the three electrode assemblies 180 illustrated in FIG. 4) and an electrolyte, and a sealing plate 120B that seals the opening of the case body 120A. The sealing plate 120B is joined to the case body 120A by welding.

[0029] The housing 120 has an upper surface 121, a lower surface 122, a first side surface 123, a second side surface 124, and two third side surfaces 125. The upper surface 121, the lower surface 122, the first side surface 123, the second side surface 124, and the third side surface 125 each have a rectangular shape.

[0030] The upper surface 121 is a plane perpendicular to the Z-axis direction (third direction) that is perpendicular to the Y-axis direction and the X-axis direction. The electrode terminals 110 are disposed on the upper surface 121. The lower surface 122 faces the upper surface 121 along the Z-axis direction.

[0031] Each of the first side surface 123 and the second side surface 124 is made of a plane perpendicular to the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has the largest area among the multiple side surfaces of the housing 120. Each of the first side surface 123 and the second side surface 124 has a rectangular shape when viewed in the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has a rectangular shape when viewed in the Y-axis direction, with the X-axis direction being the longitudinal direction and the Z-axis direction being the lateral direction.

[0032] The multiple batteries 100 are stacked such that the first side surfaces 123 and the second side surfaces 124 of the batteries 100 adjacent to each other in the Y-axis direction face each other. As a result, the positive electrode terminals 111 and the negative electrode terminals 112 are arranged alternately in the Y-axis direction in which the multiple batteries 100 are stacked.

[0033] Case body 120A and sealing plate 120B are made of metal, specifically aluminum, aluminum alloy, iron, iron alloy, or the like.

[0034] The case body 120A is formed so that it is longer in the width direction (X-axis direction) of the battery 100 than in the thickness direction (Y-axis direction) and height direction (Z-axis direction) of the battery 100. That is, when the battery 100 is viewed from the Y-axis direction, the housing 120 (case) of the battery 100 has a substantially rectangular shape with the X-axis direction (second direction) as the longitudinal direction and the Z-axis direction (third direction) as the lateral direction.

[0035] Gas release valve 130 is provided on top surface 121. When the temperature of battery 100 rises (thermal runaway) and the internal pressure of housing 120 exceeds a predetermined value due to gas generated inside housing 120, gas release valve 130 releases the gas to the outside of housing 120.

[0036] The liquid inlet 140 is provided on the top surface 121. The electrolyte is injected into the housing 120 through the liquid inlet 140. The liquid inlet 140 is sealed with a sealing member. For example, a blind rivet or other metal member can be used as the sealing member.

[0037] The positions of the gas exhaust valve 130 and the liquid injection hole 140 are not limited to those shown in FIG. 2, and can be changed as appropriate.

[0038] Next, the internal structure of the casing 120 of the battery 100 and the structure on the sealing plate 120B will be described with reference to FIGS.

[0039] 3, an insulating electrode holder 160 is provided on the outer surface of the sealing plate 120B, and the electrode terminal 110 is provided on the electrode holder 160. The positive electrode terminal 111 is provided on the positive electrode holder 161, and the negative electrode terminal 112 is provided on the negative electrode holder 162. This allows the electrode terminal 110 to be electrically insulated from the sealing plate 120B.

[0040] As shown in FIGS. 3 and 4, the positive and negative electrodes of the electrode body 180 are electrically connected to the positive terminal 111 and the negative terminal 112 by a positive current collector 171 and a negative current collector 172, respectively.

[0041] 3, an L-shaped first current collecting member 171A (positive electrode side) and a first current collecting member 172A (negative electrode side) are provided on the inner surface of the sealing plate 120B. The first current collecting members 171A and 172A are attached to the sealing plate 120B via an insulating member (not shown). Therefore, the first current collecting members 171A and 172A are electrically insulated from the sealing plate 120B.

[0042] On the positive electrode side, the first current collecting member 171A is joined to the positive electrode terminal 111, and on the negative electrode side, the first current collecting member 172A is joined to the negative electrode terminal 112. The first current collecting members 171A, 172A and the electrode terminal 110 can be joined by, for example, crimping and welding (for example, by connecting them by crimping and then welding the crimped portion).

[0043] As shown in FIG. 4, the positive electrode of the electrode body 180 is electrically connected to the second current collecting member 171B (positive electrode side), and the negative electrode of the electrode body 180 is electrically connected to the second current collecting member 172B (negative electrode side).

[0044] On the positive electrode side, the first current collecting member 171A is joined to the second current collecting member 171B. On the negative electrode side, the first current collecting member 172A is joined to the second current collecting member 172B. Methods that can be used to join the first current collecting members 171A, 172A and the second current collecting members 171B, 172B include ultrasonic welding, resistance welding, and laser welding using high-energy radiation.

[0045] Although FIG. 4 illustrates a structure in which three wound electrode bodies 180 are stacked, the scope of the present technology is not limited to this, and the structure of the electrode body 180 can be modified as appropriate. For example, it is not necessary to stack multiple wound electrode bodies. Furthermore, when multiple wound electrode bodies are stacked, the number of stacked electrode bodies can be modified as appropriate. Furthermore, a stacked electrode body may be used instead of the wound electrode body.

[0046] 4 (a state in which the electrode terminal 110 and the electrode body 180 are electrically connected), the electrode body 180 is inserted into the case body 120A. It is preferable to provide an insulating sheet between the inner surface of the case body 120A and the electrode body 180. After the opening of the case body 120A is closed with the sealing plate 120B, the outer edge of the sealing plate 120B and the inner edge of the opening of the case body 120A are joined by laser welding or the like. This forms an enclosed space within the housing 120, and the electrode body 180 is housed within that enclosed space.

[0047] When the temperature of the battery 100 rises, gas generated inside the housing 120 is intended to reach above the gas exhaust valve 130 through gaps between the housing 120, the current collecting members 171 and 172, and the electrode body 180. In the battery pack 1 including the battery 100 illustrated in Figures 1 to 4, peripheral components of the battery 100 (such as a gas duct) are arranged on the assumption that gas will be exhausted from the top surface 121 side of the housing 120.

[0048] When the internal pressure of the batteries 100 included in the battery pack 1 increases, it is preferable that the gas inside the casing 120 be reliably released through the gas release valve 130. On the other hand, due to the gas flow inside the casing 120 during thermal runaway, a large amount of internal pressure may be generated locally in a portion other than the gas release valve 130 before the internal pressure around the gas release valve 130 reaches the operating pressure of the gas release valve 130. This may cause a portion of the casing 120 other than the gas release valve 130 to rupture.

[0049] For example, in a forced short circuit test of the battery pack 1, an electrical short circuit is forcibly generated at a specific position (short circuit point) inside the casing 120. At this time, the pressure and heat of high-temperature (approximately 1200°C) gas generated from the short circuit point can cause heat loss in the casing 120 (which has a melting point of approximately 660°C in the case of an aluminum can), potentially resulting in a hole. Inside the casing 120, gas tends to flow in the direction of lower pressure loss. If the flow rate on the sealing plate 120B side (gas release valve 130 side) is relatively small, it may become more likely for cracking to occur on surfaces other than the sealing plate 120B.

[0050] 5 to 7 are diagrams showing the arrangement of gas release valves 130, 130A provided on sealing plate 120B of battery 100. As shown in Fig. 5 to 7, in battery 100 according to this embodiment, gas release valve 130 (first release valve) and gas release valve 130A (second release valve) are provided on sealing plate 120B that forms upper surface 121 (first surface) of casing 120.

[0051] The gas release valves 130, 130A are provided, for example, by forming a thin portion or a groove (notch) in a part of the housing 120 (sealing plate 120B). The thin portion or the groove may be provided on the outer surface of the sealing plate 120B, on the inner surface of the sealing plate 120B, or on both the outer and inner surfaces of the sealing plate 120B.

[0052] The shape, size, etc. of the thin-walled portion or groove portion that constitutes the gas release valves 130, 130A are changed as appropriate according to the design value of the operating pressure of the gas release valves 130, 130A.

[0053] The gas exhaust valve 130 (primary valve) is formed to open when the internal pressure of the housing 120 reaches P1 (first internal pressure). That is, the operating pressure of the gas exhaust valve 130 is P1.

[0054] The gas exhaust valve 130A (secondary valve) is formed to open when the internal pressure of the housing 120 reaches P2 (second internal pressure). That is, the operating pressure of the gas exhaust valve 130A is P2.

[0055] The operating pressure P2 of the gas release valve 130A is designed to be higher than the operating pressure P1 of the gas release valve 130. When the design operating pressure (P1) of the gas release valve 130 is set to 1, the design operating pressure (P2) of the gas release valve 130A (secondary valve) is preferably approximately 1.1 to 2 times that pressure. For example, if P1 is 2 MPa, the thin-walled portion or groove constituting the gas release valve 130A is formed so that P2 is approximately 2.2 to 4.0 MPa.

[0056] In the battery 100 of this embodiment, gas exhaust valves 130 and 130A as primary and secondary valves are provided on the same surface (top surface 121) of the rectangular housing 120, so that even if the gas exhaust valve 130 does not open as intended, the gas exhaust valve 130A on the same surface can be opened.

[0057] This prevents the surfaces of the housing 120 other than the top surface 121 (the bottom surface 122, the first side surface 123, the second side surface 124, and the third side surface 125) from unintentionally splitting open, causing ejected material from inside the housing 120 to eject in unintended directions. As a result, it is possible to prevent unintended effects on adjacent or surrounding batteries 100.

[0058] As shown in Figures 5 and 6, the gas exhaust valve 130A may be provided so as to encompass the gas exhaust valve 130, or as shown in Figure 7, the gas exhaust valve 130A may be provided so as to be spaced apart from the gas exhaust valve 130.

[0059] In this embodiment, a structure in which the gas exhaust valves 130, 130A are provided on the top surface 121 of the housing 120 is exemplified, but the scope of the present technology is not limited to this, and as long as the gas exhaust valves 130, 130A are formed on the same surface of the housing 120, the gas exhaust valves 130, 130A may be provided on a surface of the housing 120 other than the top surface 121.

[0060] In the present embodiment, the gas release valves 130, 130A and the electrode terminal 110 are arranged on the same surface of the housing 120, but the scope of the present technology is not limited thereto, and the gas release valves 130, 130A and the electrode terminal 110 may be arranged on different surfaces of the housing 120. Furthermore, the electrode terminal 110 may be arranged on a surface other than the upper surface 121, and the positive electrode terminal 111 and the negative electrode terminal 112 may be arranged on different surfaces of the housing 120.

[0061] Although the embodiments of the present technology have been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0062] 1 battery pack, 100 battery, 110 electrode terminal, 111 positive electrode terminal, 112 negative electrode terminal, 120 housing, 120A case body, 120B sealing plate, 121 upper surface, 122 lower surface, 123 first side surface, 124 second side surface, 125 third side surface, 130, 130A gas release valve, 140 liquid inlet, 160 electrode holder, 161 positive electrode holder, 162 negative electrode holder, 171, 172 current collecting member, 171A, 172A first current collecting member, 171B, 172B second current collecting member, 180 electrode body, 200 separator, 300 end plate.

Claims

1. An electrode body; a housing having a first surface formed of a flat surface and housing the electrode body; A battery, comprising: a first exhaust valve that opens when a first internal pressure acts; and a second exhaust valve that opens when a second internal pressure higher than the first internal pressure acts, provided on the first surface of the housing.

2. The battery according to claim 1 , wherein the second internal pressure is at least 1.1 times the first internal pressure.

3. The battery according to claim 1 or 2, wherein the second exhaust valve is provided to encompass the first exhaust valve.

4. The battery according to claim 1 or 2, wherein the second exhaust valve is provided so as to be spaced apart from the first exhaust valve.

5. 3. The battery according to claim 1, wherein the first and second exhaust valves are formed by grooves or thin-walled portions provided on the first surface of the housing.

6. The battery according to claim 1 or 2, wherein the housing has a rectangular shape.

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