KR20240059781A - Battery device and control method thereof - Google Patents

Abstract

A battery device according to an embodiment of the present invention includes a plurality of cell stacks including a plurality of first stacks having a first nominal voltage and a plurality of second stacks having a second nominal voltage, the plurality of cell stacks It includes a case for accommodating a sieve therein, and a plurality of connection members for electrically connecting the plurality of cell stacks to each other, wherein each of the second stacks has at least one side of one of the plurality of first stacks. It can be positioned to face one.

Description

Battery device and its control method {BATTERY DEVICE AND CONTROL METHOD THEREOF}

The present invention relates to a highly stable battery device and its control method.

Recently, high-output battery devices using non-aqueous electrolytes with high energy density are being developed. These high-output battery devices are implemented with high capacity by connecting a plurality of battery cells or devices in series or parallel so that they can be used to drive motors in devices that require high power, such as electric vehicles.

Meanwhile, in the electric vehicle market that requires high output and driving range, battery devices using high-nickel anode materials are being manufactured. However, in the case of high-nickel anode materials, thermal runaway can occur, leading to safety issues.

The purpose of the present invention is to provide a battery device and a control method thereof that can slow down the heat propagation time during thermal runaway.

A battery device according to an embodiment of the present invention includes a plurality of cell stacks including a plurality of first stacks having a first nominal voltage and a plurality of second stacks having a second nominal voltage, the plurality of cell stacks It includes a case for accommodating a sieve therein, and a plurality of connection members for electrically connecting the plurality of cell stacks to each other, wherein each of the second stacks has at least one side of one of the plurality of first stacks. It can be positioned to face one.

In this embodiment, the first plurality of laminates and the plurality of second laminates may be arranged alternately.

In this embodiment, the connecting member may include a first connecting member connecting the plurality of first laminates to each other and a second connecting member connecting the plurality of second laminates to each other.

In this embodiment, each of the first laminates can be formed by stacking a plurality of LFP battery cells.

In this embodiment, the first nominal voltage may be lower than the second nominal voltage.

In this embodiment, the first nominal voltage may be 3.2V and the second nominal voltage may be 3.6V.

In this embodiment, each of the second laminates can be formed by stacking a plurality of ternary battery cells.

In this embodiment, a control unit that selectively operates the first and second laminates based on the temperatures of the first and second laminates may be further included.

In this embodiment, a partition wall disposed between the plurality of first laminates and the plurality of second laminates may be further included.

In this embodiment, the second laminate may ignite at a lower temperature than the first laminate.

In this embodiment, at least two of the first plurality of laminates and the plurality of second laminates may each be arranged sequentially along a first direction, and may be alternately arranged along a second direction.

In addition, the battery device control method according to an embodiment of the present invention includes operating the first stack and the second stack together, and the temperature of any one of the first stack and the second stack is within a normal range. It may include a step of operating only the other battery device when the temperature exceeds the normal range, and a step of stopping operation of the battery device when the temperatures of both the first stack and the second stack are outside the normal range.

In this embodiment, before operating the first and second laminates together, if the temperature of the first laminate is below the critical temperature, only the second laminate is operated and the first laminate is preheated. Additional steps may be included.

According to an embodiment of the present invention, when an explosion or flame occurs in one cell stack, the spread of the explosion to other cell stacks can be suppressed as much as possible. Therefore, in the event of thermal runaway in an electric vehicle, etc., time can be secured for the driver or passengers to evacuate.

1 is an exploded perspective view schematically showing a battery device according to an embodiment of the present invention.
Figure 2 is a plan view of Figure 1.
Figure 3 is a plan view of a battery device according to another embodiment of the present invention.
4 is a flowchart schematically showing a control method according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. In the accompanying drawings, some components are exaggerated, omitted, or schematically shown, and the size of each component does not entirely reflect the actual size.

FIG. 1 is an exploded perspective view schematically showing a battery device according to an embodiment of the present invention, and FIG. 2 is a plan view of FIG. 1 with the upper plate omitted.

Referring to Figures 1 and 2, the battery device 1 according to an embodiment of the present invention includes a plurality of cell stacks 10 accommodated in a case 50, a partition wall 60, a connecting member 80, and a control unit 90.

Case 50 may provide an accommodation space for accommodating other components therein. Therefore, the case 50 may be provided in a form that surrounds the entire cell stack 10, and the plurality of cell stacks 10 are arranged side by side, forming multiple rows within the receiving space of the case 50. can be placed.

The case 50 may be made of a metal material to ensure rigidity, but is not limited thereto. Additionally, in order to increase the heat dissipation effect, at least a portion of the case 50 may be made of aluminum.

The case 50 may include a side wall 51 forming an internal space, a lower plate (not shown) covering the lower part of the internal space, and an upper plate 53 covering the upper part of the internal space. .

The side wall portion 51 forms the outer surface of the case 50 and may define an internal space. Accordingly, the cell stacks 10 may be accommodated within the internal space defined by the side wall portion 51 and seated on the lower plate 52 .

The lower plate supports the lower surface of the cell stacks 10 and can cool the cell stacks 10 at the same time. In order to effectively cool the cell stacks 10, a cooling passage may be disposed inside the lower plate 52. Accordingly, heat can be removed from the cell stacks 10 by the refrigerant flowing through the cooling passage formed in the lower plate 52.

The case 50 may be provided with a partition wall 60 that is disposed across the internal space formed by the side wall portion 51 and divides the internal space into a plurality of accommodation spaces. Accordingly, at least a portion of the partition wall 60 may be fastened to the side wall portion 51.

The partition wall 60 may be coupled to the case 50 to reinforce the overall rigidity of the case 50. Additionally, by being disposed between the cell stacks 10, it is possible to suppress the spread of gas or flame between the cell stacks 10.

In this embodiment, the partition wall 60 may be disposed between two cell stacks 10 arranged side by side. Both ends of the partition 60 may be fastened to the side wall 51 of the case 50, or may be fastened to another partition 60 to divide the internal space formed by the side wall 51 into a plurality of accommodation spaces. . Accordingly, the plurality of cell stacks 10 may be distributed and arranged in a plurality of accommodation spaces divided by the side wall portion 51 and the partition wall 60.

The partition wall 60 may be welded to the case 50 or may be fixedly fastened to the case 50 through a fastening means such as bolts or screws.

The connection member 80 is made of a conductive material and can electrically connect terminals of one cell stack 10 and other neighboring cell stacks 10 to each other. For this purpose, the connecting member 80 may include a bus-bar or cable. Both ends of the connecting member 80 may be fastened to the terminals of the cell stacks 10 through fastening members P such as bolts.

The cell stacks 10 of this embodiment may be connected to each other in series or parallel through the connection member 80. Additionally, if necessary, some of the cell stacks 10 may be connected in series and some may be connected in parallel.

The connecting member 80 according to this embodiment can be formed by processing a flat rod-shaped conductive member. Additionally, the connecting member 80 may be made of a flexible material. However, the configuration of the present invention is not limited to this.

The cell stack 10 may include secondary battery cells capable of charging and discharging. Each cell stack 10 may be formed into a hexahedral shape by stacking a plurality of battery cells in the thickness direction, and may be housed in a separate module case or fixed in a stacked state by a bracket or the like.

The cell stack 10 may be provided with at least one terminal on one side. The terminal may be a conductive member provided in the cell stack 10 to electrically connect the battery cells to the outside. The terminal may include a positive terminal (+) and a negative terminal (-), and each cell stack 10 may be electrically connected to each other through a connection member 80 fastened to the terminal.

There may be a plurality of cell stacks 10, and each cell stack 10 may have at least one battery cell therein.

In this embodiment, the cell stack 10 may include a first stack (S1) and a second stack (S2).

The first stack (S1) and the second stack (S2) may have different nominal voltages.

For example, the first stack (S1) may have a first nominal voltage and the second stack (S2) may have a second nominal voltage, and the first and third nominal voltages may be different.

The first nominal voltage may be 2.0V to 3.7V, and for this purpose, the first stack (S1) can be formed by stacking LFP battery cells including lithium iron phosphate. LFP batteries refer to batteries that use lithium iron phosphate (Li-FePO ₄ ) as the anode material. They are relatively inexpensive, have a long lifespan, and do not easily explode even at high temperatures above 350°C, so they have excellent stability. On the other hand, it has the disadvantages of low energy density, short driving distance, low instantaneous output, and heavy weight.

The second nominal voltage may be 2.5V to 4.3V, and for this purpose, the second stack (S2) may be formed by stacking ternary battery cells. For example, it may include battery cells using cathode materials with a nickel (Ni) content of 60% or more, such as NCM (nickel, cobalt, manganese) battery cells and NCA (nickel, cobalt, aluminum) battery cells. Ternary battery cells have high energy density, so they have a long driving distance and a short time to charge the battery, but they have the disadvantage of being more expensive than LFP batteries and igniting at a lower temperature than LFP batteries, so the possibility of thermal runaway is relatively high.

In the battery device 1 of this embodiment, the first stack S1, which has relatively high resistance to thermal runaway, may be disposed around the second stack S2. Specifically, one first stack (S1) is disposed adjacent to at least one second stack (S2), and the second stack (S2) has at least one side of one of the first stack (S2). It can be arranged to face S1). Accordingly, one of the second stacks S2 may face the first stacks S1 or the side wall portion 51, but may be arranged not to directly face the other second stacks S2. Referring to FIG. 2 , in the battery device 1 of this embodiment, the first stack S1 and the second stack S2 are arranged alternately within the case 50.

Meanwhile, in the battery device 1 according to this embodiment, the first stacks S1 may be electrically connected to each other, and the second stacks S2 may be electrically connected to each other. To this end, the above-described connecting member 80 includes first connecting members 80a that interconnect the first laminates (S1), and second connecting members that interconnect the second laminates (S2). (80b) may be included.

Additionally, it may include a control unit 90 that selectively supplies electrical energy to the outside depending on the situation. The control unit 90 is connected to the first connection members 80a and the second connection members 80b, respectively, and controls power supplied through the first connection members 80a or the second connection members 80b. It can be selectively supplied externally (for example, to the motor of an electric vehicle, etc.). For this purpose, the control unit may include a switch.

The control unit 90 may supply power supplied from the first stack (S1) to the outside in a low output section or a general output section, and may supply power supplied from the second stack (S2) to the outside in a high output group. Here, the low output section or general output section may include a constant speed driving section or a downhill section in an electric vehicle. Additionally, the high-output section may include an acceleration section or an uphill section.

Additionally, the control unit 90 of this embodiment can selectively operate the first stack (S1) and the second stack (S2) based on the temperatures of the first stack (S1) and the second stack (S2). there is.

Figure 4 is a flowchart schematically showing a control method according to an embodiment of the present invention.

Referring to FIG. 4 , the control unit 90 of this embodiment can check the temperature (T ₁ ) of the first laminate (S1) when the operation of the battery device (1) begins (P2). In this process, if the temperature (T ₁ ) of the first stack (S1) is confirmed to be less than the critical temperature of 10°C, the control unit 90 operates only the second stack (S2) to supply power to the outside, and 1 The laminate (S1) can be preheated (P3).

The LFP battery cell constituting the first stack (S1) has the disadvantage of poor mobility at low temperatures. However, in the battery device 1 of this embodiment, since the first stack S1 is disposed adjacent to the second stack S2, the second stack S2 is preferentially used, and in this process, the second stack S1 is disposed adjacent to the second stack S2. The first laminate (S1) can be preheated using the heat generated from the sieve (S2). For example, the refrigerant flowing in the cooling passage absorbs heat energy from the second stack (S2), and the heat energy of the absorbed refrigerant is supplied to the first stack (S1) to increase the temperature of the first stack (S1). It can be raised. However, the configuration of the present invention is not limited to this, and various methods can be used as long as heat energy can be supplied to the first laminate (S1). For example, the preheating heating element may be heated using the power supplied from the second laminate S2, and the first laminate S1 may be preheated using the preheating heating element. In this case, a heating element for preheating may be coupled to at least one side of the first laminate (S1). In addition, when the battery device is configured to remove the partition wall 60 or lower the height of the partition wall 60 so that at least a portion of the first stack (S1) and the second stack (S2) face each other directly, the second stack The first laminate S1 may be preheated by transferring the heat energy of the sieve S2 directly to the first laminate S1. In addition, when the partition wall 60 is formed of a material with high thermal conductivity, the heat energy of the second stack S2 is indirectly transferred to the first stack S1 through the partition wall 60, thereby forming the first stack S1. The temperature of (S1) can be increased.

When the temperature (T ₁ ) of the first stack (S1) rises to 10°C or higher through the above-described heat energy, the control unit 90 operates both the first stack (S1) and the second stack (S2) This allows power to be supplied externally (P4). During this process, the control unit 90 can continuously determine the temperatures (T ₁ and T ₂ ) of the first and second stacks (S1 and S2).

Additionally, if the temperature (T ₁ , T ₂ ) of either the first stack (S1) or the second stack (S2) is outside the normal range, the control unit 90 may operate only the other one. To this end, the control unit 90 repeatedly performs step P5 of checking the temperature (T ₂ ) of the second stack (S2) and step P8 of checking the temperature (T ₁ ) of the first stack (S1). You can.

When both the second stack (S2) and the first stack (S1) are within the normal temperature range, the control unit 90 ensures that both the first stack (S1) and the second stack (S2) operate normally. It is determined that the P4 step of operating the first stack (S1) and the second stack (S2) together can be maintained. In this embodiment, the normal operating temperature range T ₁ of the first laminate S1 may be expressed as Equation 1 below. And the normal operating temperature range T ₂ of the second laminate S2 may be expressed as Equation 2 below.

Equation 1) 10℃ ≤ T ₁ ≤ 80℃

Equation 2) -20℃ ≤ T ₂ ≤ 60℃

When the battery device 1 of this embodiment is mounted on an electric vehicle, when both the first stack S1 and the second stack S2 operate in a normal temperature range (hereinafter referred to as normal range), the control unit 90 regenerates. During braking, the second stack (S2) can be charged preferentially.

Meanwhile, in step P5, when the temperature (T ₂ ) of the second stack (S2) exceeds the upper limit of the normal range (for example, 60°C), the control unit 90 controls the temperature (T ₁ ) of the first stack (S1) ) can be checked to see if it exceeds the upper limit of the normal range (e.g. 80°C) (P6). In step P6, if the temperature (T ₁ ) of the first stack (S1) does not exceed the upper limit of the normal range, the control unit 90 supplies power to the outside using only the first stack (S1) and The sieve (S2) can be cooled (P7).

In addition, even if the temperature (T ₂ ) of the second laminated body (S2) does not exceed the upper limit of the normal range in step P5, if the temperature (T ₁ ) of the first laminated body (S1) exceeds the upper limit of the normal range (P8) , the control unit 90 operates only the second stack (S2) to supply power to the outside and cool the first stack (S1) (P9).

Meanwhile, in the P5 stage, the temperature (T ₂ ) of the second laminated body (S2) exceeds the upper limit of the normal range, and in the P6 stage, the temperature (T ₁ ) of the first laminated body (S1) exceeds the upper limit of the normal range. In this case, since the temperature of all cell stacks 10 is outside the normal range, the control unit 90 may display a warning to the worker or user and stop the operation of the battery device 1. In this case, a device that operates only on the power of the battery device 1, such as an electric vehicle, may be dangerous because its operation suddenly ends when the operation of the battery device 1 is suddenly stopped. Therefore, the control unit 90 can supply additional power for a certain period of time so that the vehicle can be moved to a safe place. In this case, the control unit 90 can supply power through the relatively safe first stack (S1).

The battery device 1 of this embodiment configured in this way can suppress heat propagation to other cell stacks 10 as much as possible during thermal runaway. The first laminate (S1) may ignite at a temperature of 475°C or higher (e.g., LFP battery cell), and the second laminate (S2) may ignite at a temperature of 150°C or higher (e.g., NCM battery cell, Nickel content can be 88%).

The first laminate (S1) has relatively higher stability against flame or explosion than the second laminate (S2), so if an explosion or flame occurs in any one of the second laminate (S2), The disposed first laminate S1 may serve to block or delay the propagation of explosion by-products or flames. Accordingly, it is possible to minimize the direct influence of the explosion by-products or flames on the other second laminated body (S2), and thus the spread of the explosion to the other second laminated body (S2) can be suppressed as much as possible. Additionally, this suppression of heat propagation can provide the effect of ensuring time for drivers or passengers to evacuate in the event of thermal runaway in an electric vehicle.

Meanwhile, the present invention is not limited to the above-described embodiments and various modifications are possible.

Figure 3 is a plan view of a battery device according to another embodiment of the present invention.

Referring to FIG. 3, the battery device of this embodiment includes at least two first stacks (S1) arranged in a line along a first direction (Y-axis direction), and at least two stacks S1 arranged in a line along the first direction. It may include a second laminate (S2).

A plurality of first laminated bodies S1 arranged in a row and a plurality of second laminated bodies S2 arranged in a row may be alternately arranged along the second direction (X-axis direction).

When configured in this way, the connection between the first stacks S1 and the second stacks S2 becomes easy, so the connection member 80 can be arranged more simply.

In this embodiment, since the two second laminates S2 are arranged sequentially, there is a possibility that thermal runaway can easily propagate between them. Accordingly, the two second stacked bodies (S2) may be configured so that flame or gas caused by an explosion is discharged toward the first stacked body (S1). Additionally, a blocking member 70 may be disposed between the two second stacked bodies S2 arranged in a row.

The blocking member 70 may be formed of a member having flame retardancy or flame resisting performance and may be formed in the form of a sheet or pad. Here, flame retardant performance refers to the ability to prevent the spread of combustion, and flame retardant performance refers to the ability to prevent combustion even if a fire occurs. Accordingly, the blocking member 70 may have a combustibility level that does not cause combustion to spread, or may have a non-flammable property.

The blocking member 70 of this embodiment may include mica or silicone, and may be composed of a single sheet, or may be formed by laminating thin plates of different materials. For example, the blocking member 70 can be formed by laminating an insulating layer such as rubber or polyurethane on at least one of both sides of a mica sheet. However, it is not limited to this.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations are possible without departing from the technical spirit of the present invention as set forth in the claims. This will be self-evident to those with ordinary knowledge in the field. Additionally, each embodiment may be implemented in combination with each other.

1: Battery unit
10: Cell stack
60: Bulkhead
70: blocking member
80: connection member
90: control unit
S1: first laminate
S2: second laminate

Claims (13)

a plurality of cell stacks comprising a first plurality of stacks having a first nominal voltage and a plurality of second stacks having a second nominal voltage;
A case accommodating the plurality of cell stacks therein; and
a plurality of connection members electrically connecting the plurality of cell stacks to each other;
Including,
A battery device in which each second stack is disposed so that at least one side faces any one of the plurality of first stacks.
According to paragraph 1,
A battery device including the plurality of first stacks and the plurality of second stacks being alternately arranged.
The method of claim 2, wherein the connecting member is:
a first connecting member connecting the plurality of first laminates to each other; and
a second connecting member connecting the plurality of second laminates to each other;
A battery device comprising:
The method of claim 1, wherein each of the first laminates:
A battery device formed by stacking multiple LFP battery cells.
According to paragraph 1,
The battery device wherein the first nominal voltage is lower than the second nominal voltage.
According to clause 5,
The first nominal voltage is 2.0V to 3.7V, and the second nominal voltage is 2.5V to 4.3V.
The method of claim 1, wherein each second laminate:
A battery device formed by stacking multiple ternary battery cells.
According to paragraph 1,
The battery device further includes a control unit that selectively operates the first and second stacks based on the temperatures of the first and second stacks.
According to paragraph 1,
A battery device further comprising a partition wall disposed between the plurality of first stacks and the plurality of second stacks.
According to paragraph 1,
A battery device in which the second laminate ignites at a lower temperature than the first laminate.
According to paragraph 1,
A battery device in which at least two of the first plurality of laminates and the plurality of second laminates are each arranged sequentially along a first direction and alternately arranged along a second direction.
A method of controlling the battery device according to claim 1,
Operating the first laminate and the second laminate together;
If the temperature of either the first laminate or the second laminate is outside the normal range, operating only the other one; and
stopping operation of the battery device when the temperatures of both the first stack and the second stack are outside the normal range;
A battery device control method comprising:
The method of claim 12, before operating the first and second laminates together,
If the temperature of the first stack is below the critical temperature, the battery device control method further includes operating only the second stack and preheating the first stack.

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