Battery pack and protection method thereof

Abstract

To provide a battery pack and a protection method thereof.SOLUTION: A battery pack comprises: a plurality of battery cells between a first pack terminal and a second pack terminal; a plurality of balancing resistors connected with the plurality of battery cells, respectively; a plurality of balancing switches connected with the plurality of battery cells and the plurality of balancing resistors, respectively, and connecting the corresponding battery cell with the corresponding balancing resistor in turn-on to constitute a closed circuit; a rack fuse between the plurality of battery cells and the first pack terminal or the second pack terminal; a current sensor between the plurality of battery cells and the first pack terminal or the second pack terminal; and a controller constituted to sense pack current between the first pack terminal and the second pack terminal via the current sensor to control the plurality of balancing switches. The controller is constituted to sense short-circuit between the first pack terminal and the second pack terminal on the basis of the pack current and to turn all of the plurality of balancing switches on.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a battery pack and a protection method thereof, and more particularly to a battery pack and a protection method thereof that can prevent an extremely large reverse voltage from occurring in a battery cell due to the melting of a cell fuse. [Background technology]

[0002] A secondary battery is a battery that can be charged and discharged, unlike a primary battery that cannot be charged. Small batteries are used in small portable electronic devices such as smartphones, feature phones, laptops, digital cameras and camcorders, while large batteries are widely used in hybrid vehicles, electric vehicles and energy storage systems. Electric vehicle batteries are used as a power source to drive motors. Generally, large batteries are configured into battery cells, battery modules and battery packs.

[0003] A battery cell is a basic unit of a secondary battery that can be used by charging and discharging electrical energy, and includes an electrode assembly consisting of a positive electrode and a negative electrode, a case for accommodating the electrode assembly, and an electrode terminal connected to the electrode assembly. A battery module is a battery assembly in which a certain number of battery cells are bundled together and placed in a frame to protect the battery cells from external impact, heat, vibration, etc. A battery pack is a battery system in its final form that is completed by equipping the battery module with various control systems and protection systems such as a battery management system (BMS) and a cooling system. The battery module may be called a battery block or block, and the battery pack may be called a battery rack or rack.

[0004] A battery cell may have a cell fuse to protect the inside of the battery cell from an overcurrent. A battery pack may also have a main fuse to protect the battery pack from an overcurrent, and the main fuse may be called a rack fuse. If an overcurrent occurs due to a short circuit at the load end or output end, the rack fuse generally blows first. However, if the cell fuse blows before the rack fuse, a reverse voltage exceeding the withstand voltage may be applied to the battery cell. An arc may occur in the battery cell, and even the battery cell may catch fire.

[0005] The above information disclosed in such background of the invention is intended to enhance the understanding of the background of the invention only, and therefore may include information that does not constitute prior art. Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a battery pack capable of protecting a battery cell even if an extremely large reverse voltage is applied to the battery cell due to the melting of a cell fuse.

[0007] Another problem to be solved by the present invention is to provide a method for protecting a battery pack that can protect a battery cell even if an extremely large reverse voltage is applied to the battery cell due to the melting of a cell fuse.

[0008] However, the technical problems that the present invention aims to solve are not limited to the problems described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below. [Means for solving the problem]

[0009] According to an aspect of the present invention, a battery pack includes a plurality of battery cells between a first pack terminal and a second pack terminal, a plurality of balancing resistors respectively connected to the plurality of battery cells, a plurality of balancing switches respectively connected to the plurality of battery cells and the plurality of balancing resistors and each configured to connect a corresponding battery cell and a corresponding balancing resistor when turned on to form a closed circuit, a rack fuse between the plurality of battery cells and the first pack terminal or the second pack terminal, a current sensor between the plurality of battery cells and the first pack terminal or the second pack terminal, and a controller configured to sense a pack current between the first pack terminal and the second pack terminal via the current sensor and control the plurality of balancing switches. The controller is configured to sense a short-circuit between the first pack terminal and the second pack terminal based on the pack current and turn on all of the plurality of balancing switches.

[0010] According to one example, each of the plurality of battery cells also includes an electrode assembly having a first cell terminal and a second cell terminal, a positive electrode connected to the first cell terminal, a negative electrode connected to the second cell terminal, and a separator between the positive electrode and the negative electrode, and a cell fuse between the electrode assembly and the first cell terminal or the second cell terminal.

[0011] As another example, the controller may detect a short circuit based on pack current exceeding a preset threshold.

[0012] According to yet another example, the controller may be configured to sense removal of the short circuit when all of the balancing switches are turned on and determine whether the rack fuse is blown.

[0013] As yet another example, the controller may sense the removal of the short circuit based on the pack current being reduced below a preset reference value.

[0014] According to yet another example, the controller may be configured to turn off all of the balancing switches if the rack fuse is not blown.

[0015] According to yet another example, the battery pack further includes a plurality of battery blocks coupled between the first pack terminal and the second pack terminal, each having a plurality of battery cells, a plurality of balancing circuits each having a plurality of balancing resistors and a plurality of balancing switches, a plurality of block control circuits each controlling the plurality of balancing switches of a corresponding balancing circuit, and a main controller configured to sense pack current and a state of a rack fuse and to control the plurality of block control circuits.

[0016] According to yet another example, the controller also includes a plurality of block control circuits and a main controller.

[0017] According to yet another example, the main controller may detect a short circuit between a first pack terminal and a second pack terminal based on the pack current, and transmit commands to a plurality of block control circuits to turn on all of a plurality of balancing switches in a plurality of balancing circuits.

[0018] According to yet another example, the multiple block control circuits may be configured to collect cell voltages of the multiple battery cells of the corresponding battery blocks and individually control multiple balancing switches of the corresponding balancing circuits to equalize the cell voltages of the multiple battery cells.

[0019] According to a method for protecting a battery pack according to an aspect of the present invention, the battery pack includes a plurality of battery cells between a first pack terminal and a second pack terminal, a plurality of balancing resistors respectively connected to the plurality of battery cells, a plurality of balancing switches respectively connected to the plurality of battery cells and the plurality of balancing resistors and each connecting a corresponding battery cell to a corresponding balancing resistor when turned on to form a closed circuit, a rack fuse between the plurality of battery cells and the first pack terminal or the second pack terminal, a current sensor between the plurality of battery cells and the first pack terminal or the second pack terminal, and a controller configured to control the plurality of balancing switches. The method for protecting the battery pack includes the steps of sensing a pack current between the first pack terminal and the second pack terminal via the current sensor, sensing a short circuit between the first pack terminal and the second pack terminal based on the pack current, and turning on all of the plurality of balancing switches based on the detection of the short circuit.

[0020] According to one example, the step of sensing a short circuit also includes the steps of comparing the pack current to a preset reference value and determining that a short circuit has occurred if the pack current exceeds the preset reference value.

[0021] According to another example, the method may further include, after turning on all of the balancing switches, detecting whether the short circuit has been removed, and if the short circuit has been removed, determining whether the rack fuse has been blown.

[0022] According to yet another example, the step of sensing removal of the short circuit may include the steps of comparing the pack current with a preset reference value and determining that the short circuit has been removed if the pack current is reduced to below the preset reference value.

[0023] According to yet another example, the method may further include, after the step of determining whether the rack fuse is blown, turning off all of the balancing switches if it is determined that the rack fuse is not blown.

[0024] According to yet another example, each of the multiple battery cells includes an electrode assembly having a first cell terminal and a second cell terminal, a positive electrode connected to the first cell terminal, a negative electrode connected to the second cell terminal, and a separator between the positive electrode and the negative electrode, and a cell fuse between the electrode assembly and the first cell terminal or the second cell terminal. Effect of the Invention

[0025] According to the present invention, even if a short circuit occurs at the output end or the load end, or if the cell fuse melts before the rack fuse, secondary damage due to reverse voltage is prevented, so that the battery pack can be used safely.

[0026] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects not mentioned will be clearly understood by those skilled in the art from the description of the invention described below. [Brief description of the drawings]

[0027] The following drawings attached to this application illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. [Figure 1] FIG. 1 illustrates a block diagram of a battery pack according to one embodiment of the present invention. [Diagram 2] 4 is a flowchart illustrating a method for protecting a battery pack according to an embodiment of the present invention. [Diagram 3] FIG. 13 illustrates a block diagram of a battery pack according to another embodiment of the present invention. [Figure 4] FIG. 4 is a diagram illustrating one block of the battery pack of FIG. 3. [Figure 5A] FIG. 2 illustrates a perspective view of a cylindrical battery cell mounted in a battery pack according to one embodiment of the present invention. [Figure 5B] FIG. 2 illustrates a cross-sectional view of a cylindrical battery cell mounted in a battery pack according to one embodiment of the present invention. [Figure 6] 1 is a partial perspective view illustrating the structure of a pouch-type battery cell mounted in a battery pack according to one embodiment of the present invention; [Figure 7A] 1 is a perspective view of a rectangular battery cell mounted in a battery pack according to an embodiment of the present invention; [Figure 7B] 7B is a cross-sectional view taken along the cut line (II-II) in FIG. 7A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and claims should not be interpreted as being limited to their general or dictionary meanings, but should be interpreted as meanings and concepts that correspond to the technical ideas of the present invention, based on the principle that the inventor can appropriately define the concepts of terms in order to best describe his / her invention. Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention, and do not represent the technical ideas of the present invention, and therefore, at the time of filing this application, there may be various equivalents and modifications that can replace them.

[0029] As used herein, "comprise," "include," and / or "comprising," "including" specify the presence of a stated feature, number, step, operation, member, element, and / or group thereof, but do not exclude the presence or addition of one or more other features, numbers, operations, members, elements, and / or groups. When describing an embodiment of the present invention, the words "may" and "also" also include "one or more embodiments of the present invention."

[0030] In order to facilitate understanding of the invention, the accompanying drawings are not drawn to scale, and the dimensions of some components may be exaggerated. In addition, the same reference numerals may be used to refer to the same components in different embodiments.

[0031] A statement that two comparison objects are "identical" means that they are "substantially identical." Thus, substantially identical also includes cases where there is a deviation that is considered to be a low level in the art, for example, within 5%. In a given region, uniformity of a certain parameter may mean uniformity in the average sense.

[0032] It should be understood that even if the terms "first", "second", etc., are used to describe various elements, the elements are not limited by these terms, and that these terms are merely used to distinguish one element from another element, and that a first element is also a second element unless specifically stated to the contrary.

[0033] Throughout the specification, unless specifically stated to the contrary, each element may be in the singular or in the plural.

[0034] When an arbitrary structure is arranged on the "top (or bottom)" of a component, or on the "top (or bottom)" of a component, it may mean that the arbitrary structure is not only arranged in contact with the top surface (or bottom surface) of the component, but also that other structures may be interposed between the component and the arbitrary structure arranged on the top (or bottom) of the component.

[0035] In addition, when a certain component is described as being "coupled", "coupled" or "connected" to another component, the components may be directly coupled or connected to each other, but it should be understood that other components may be "interposed" between each component, or each component may be "coupled", "coupled" or "connected" via other components. In addition, when a part is described as being electrically coupled to another part, this includes not only the case where they are directly coupled, but also the case where they are coupled via another element in between.

[0036] Throughout the specification, "A and / or B" means A or B, or A and B, unless specifically stated to the contrary. That is, "and / or" includes all or any combination of the listed items. "C through D" means at least C and at most D, unless specifically stated to the contrary.

[0037] FIG. 1 illustrates a block diagram of a battery pack according to one embodiment of the present invention.

[0038] 1, the battery pack 100 includes a battery 110 between a first pack terminal PT1 and a second pack terminal PT2, a balancing circuit 120, and a controller 130. The battery pack 100 is coupled to a load 10 via the first pack terminal PT1 and the second pack terminal PT2, and may supply energy stored in the battery 110 to the load 10. Instead of the load 10, a charging device may be coupled to the first pack terminal PT1 and the second pack terminal PT2, and the charging device may supply energy for charging the battery 110.

[0039] The battery pack 100 includes a rack fuse F R Also includes rack fuse F R may be coupled between the battery 110 and the first pack terminal PT1. According to another example, a rack fuse F R may be coupled between battery 110 and second pack terminal PT2.

[0040] Rack Fuse F R If a current of a preset magnitude or greater flows through the rack fuse F, it melts down and cuts off the large current path through the battery 110. R When the rack fuse F is blown, R A very large reverse voltage is applied across the rack fuse F R The rack fuse F has a voltage resistance that can withstand a large reverse voltage. R If a reverse voltage exceeding the withstand voltage of the rack fuse F is applied, the fuse will be blown. R An arc can occur between the terminals of the switch, causing a fire and damaging internal components.

[0041] The controller 130 is a rack fuse F R For example, the controller 130 may sense the state of the rack fuse F R For example, the controller 130 may determine whether the rack fuse F is blown. R Based on the potential difference between both ends of the rack fuse F R The status of the

[0042] Although not shown in FIG. 1, the battery pack 100 may also include a switch between the battery 110 and the first pack terminal PT1 or the second pack terminal PT2, and the controller 130 may control the opening and closing of the switch. The switch may also include a charge control switch and a discharge control switch. If the charge control switch is opened, the battery 110 may be discharged but the charging of the battery 110 may be cut off. If the discharge control switch is opened, the battery 110 may be charged but the discharging of the battery 110 may be cut off. The switch may be, for example, a relay switch.

[0043] The battery pack 100 includes a current sensor for the controller 130 to sense the discharge current from the battery 110 and the charge current for charging the battery 110. The discharge current and the charge current of the battery 110 are referred to as the pack current. In one example, the current sensor is a shunt resistor R between the battery 110 and the second pack terminal PT2. S The shunt resistance R S is also coupled between battery 110 and first pack terminal PT1.

[0044] The controller 130 is connected to a shunt resistor R S The controller 130 may sense the magnitude of the pack current based on the voltage across the shunt resistor R S and detects a short-circuit between first pack terminal PT1 and second pack terminal PT2 based on the pack current. For example, if controller 130 detects a pack current that exceeds a preset reference value, it may determine that a short-circuit has occurred between first pack terminal PT1 and second pack terminal PT2.

[0045] The battery 110 includes a plurality of battery cells C1, C2, C3, . . . , C n It also includes battery cells C1, C2, C3, ..., C n is a part that stores power and is also a rechargeable secondary battery. For example, battery cells C1, C2, C3, ..., C nThe battery may include at least one selected from the group consisting of a lithium ion battery, a lithium polymer battery, a nickel cadmium battery, a nickel metal hydride battery (Ni-MH), a nickel zinc battery (Ni-Zn), a lead acid battery, and the like.

[0046] Battery cells C1, C2, C3, …, C n , C1, C2, C3, . . . , C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22, C23, . . . , C30, C24, C25, C26, C27, C28, C2 n The number and connection configuration of the battery cells C1, C2, C3, ..., C4 may be determined according to the output voltage and power storage capacity required for the battery pack 100. n Each may be collectively referred to as a battery cell C.

[0047] The battery cell C includes an electrode assembly connected in series between a first cell terminal and a second cell terminal, and a cell fuse F. C The electrode assembly also includes a positive electrode E connected to the first cell terminal. P , a negative electrode E connected to the second cell terminal N , and positive electrode E P and negative electrode E N Located between the positive electrode E P and negative electrode E N The first cell terminal is a positive terminal of the battery cell C, and the second cell terminal is a negative terminal of the battery cell C.

[0048] Self-Fuse F C If a current exceeding a preset level flows, the fuse melts down and cuts off the current path through the battery cell C, thereby preventing serious dangers such as the electrode assembly in the battery cell C catching fire or exploding.

[0049] 1, when a short circuit occurs between the first pack terminal PT1 and the second pack terminal PT2, for example, when a load 10 with a short circuit is connected between the first pack terminal PT1 and the second pack terminal PT2, a very large pack current will be generated. If a very large pack current occurs due to a short circuit, a rack fuse F having a large withstand voltage is generally used. R However, battery cells C1, C2, C3, ..., C n Cell Fuse F C Any one of the rack fuses F R If the blown cell fuse F C A large reverse voltage will be generated across both ends of the

[0050] The magnitude of the reverse voltage is the battery cells C1, C2, C3, …, C n The magnitude of the total voltage between the first pack terminal PT1 and the second pack terminal PT2 is also large enough to correspond to the pack voltage between the first pack terminal PT1 and the second pack terminal PT2. For example, if the resistance between the first pack terminal PT1 and the second pack terminal PT2 is approximately 0 due to a short circuit, the blown cell fuse F C A reverse voltage corresponding to the pack voltage is applied across both ends of the cell fuse F. C The voltage resistance of the cell fuse F is exceeded and the fuse is blown. C A reverse voltage exceeding the breakdown voltage of the cell fuse F C The arc may cause an arc to occur in the battery cell C. The arc may damage the separator of the battery cell C and cause the positive electrode E of the electrode assembly to break. P and negative electrode E N and may come into contact with each other, and in the worst case, the battery cell C may catch fire or even explode.

[0051] In the battery pack 100 of the present invention, when a short circuit occurs between the first pack terminal PT1 and the second pack terminal PT2, the rack fuse F R Before the cell fuse F is blown, CEven if one of the cell fuses is blown first, the blown cell fuse F C It is possible to prevent a reverse voltage exceeding the withstand voltage from occurring across both ends.

[0052] The balancing circuit 120 includes a plurality of battery cells C1, C2, C3, . . . , C n Multiple balancing resistors R B1 ,R B2 ,R B3 ,…,R Bn and multiple balancing switches S B1 ,S B2 ,S B3 ,…,S Bn Balancing switch S B1 ,S B2 ,S B3 ,…,S Bn Each of the battery cells C1, C2, C3, ..., C n The corresponding battery cells and the balancing resistor R B1 ,R B2 ,R B3 ,…,R Bn The balancing switch S B1 ,S B2 ,S B3 ,…,S Bn When each is turned on, the corresponding battery cell and the corresponding balancing resistor are connected to each other to form a closed circuit.

[0053] As shown in FIG. 1, the positive and negative terminals of the first battery cell C1 are connected in series with a first balancing resistor R B1 and the first balancing switch S B1 The first balancing switch S B1 When is turned on, the first battery cell C1 and the first balancing resistor R B1 form a closed circuit, and both terminals of the first battery cell C1 are connected to the first balancing resistor R B1 is directly connected to both ends of the

[0054] For example, the cell voltage of the first battery cell C1 is lower than that of the other battery cells C2, C3, ..., C n If the cell voltage is higher than the cell voltage of the first balancing switch S B1 is turned on, and the energy stored in the first battery cell C1 is transferred to the first balancing resistor R B1 , C1, the cell voltage of the first battery cell C1 is consumed through the other battery cells C2, C3, ..., C n The cell voltage may be as low as

[0055] The controller 130 senses the pack current flowing through the battery 110 between the first pack terminal PT1 and the second pack terminal PT2 via the current sensor and controls the balancing switch S B1 ,S B2 ,S B3 ,…,S Bn The controller 130 may be configured to control the rack fuses F R According to the present invention, if the controller 130 detects a short circuit between the first pack terminal PT1 and the second pack terminal PT2 based on the pack current, the controller 130 turns on the balancing switch S B1 ,S B2 ,S B3 ,…,S Bn may be configured to turn on both.

[0056] A short circuit causes rack fuse F R If the rack fuse F blows first, R Since the rack fuse F is designed to have a withstand voltage higher than the reverse voltage corresponding to the pack voltage, the battery pack 100 can be safely protected. R More Cell Fuse F C For example, the cell fuse F of the first battery cell C1 C Even if the balancing switch S is blown first, the balancing switch S B1 ,S B2 ,S B3 ,…,S Bnare both turned on, the reverse voltage applied to the first battery cell C1 is B1 When a voltage is applied across both ends of the first battery cell C1, the cell fuse F C This can prevent arcing from occurring between the terminals.

[0057] FIG. 2 is a flowchart illustrating a method for protecting a battery pack according to an embodiment of the present invention.

[0058] 2 in conjunction with FIG. 1, the controller 130 includes a shunt resistor R S The magnitude of the pack current is sensed via the voltage across both ends, and the occurrence of a short circuit between first pack terminal PT1 and second pack terminal PT2 can be sensed via the pack current exceeding a preset reference value (S10).

[0059] If the controller 130 detects that a short circuit has occurred, it immediately switches all the balancing switches S B1 ,S B2 ,S B3 ,…,S Bn The balancing switch S is turned on. B1 ,S B2 ,S B3 ,…,S Bn can be controlled (S20).

[0060] A short circuit causes rack fuse F R The rack fuse F R If the fuse is blown, the electrical connection between battery 110 and first pack terminal PT1 is cut off, and the pack current may be reduced to 0. Controller 130 may detect that the short circuit has been released via the pack current being equal to or less than a preset reference value (S30).

[0061] Also, a momentary inrush current may cause the controller 130 to sense that a short circuit has occurred. In that case, the rack fuse F RAlthough the pack current may not have blown, the pack current may be reduced to a normal level, and the controller 130 may sense that the short has been removed through the pack current being reduced to a normal level (S30).

[0062] The controller 130 is a rack fuse F R If a short circuit occurs, the rack fuse F R If the balancing switches S are not blown, the controller 130 determines that there is no actual short circuit and resets all the balancing switches S B1 ,S B2 ,S B3 ,…,S Bn The balancing switch S B1 ,S B2 ,S B3 ,…,S Bn However, the rack fuse F R If it has blown, then the rack fuse F R Since the battery pack 100 cannot be used until the battery is replaced, the controller 130 may terminate the protection operation.

[0063] FIG. 3 illustrates a block diagram of a battery pack according to another embodiment of the present invention.

[0064] 3, the battery pack 200 includes a plurality of blocks 201, 202, and 203 between a first pack terminal PT1 and a second pack terminal PT2, and a main controller 240. The battery pack 200 may be connected to a load 20 via the first pack terminal PT1 and the second pack terminal PT2.

[0065] The multiple blocks 201, 202, 203 also include a first battery block 210a, a second battery block 210b, and a third battery block 210c, a first balancing circuit 220a, a second balancing circuit 220b, and a third balancing circuit 220c, and a first block control circuit 230a, a second block control circuit 230b, and a third block control circuit 230c, respectively.

[0066] The first battery block 210a, the second battery block 210b, and the third battery block 210c are parts that store power and each includes a plurality of battery cells. The first balancing circuit 220a, the second balancing circuit 220b, and the third balancing circuit 220c are circuits for equalizing the cell voltages of the battery cells included in the first battery block 210a, the second battery block 210b, and the third battery block 210c. The first block control circuit 230a, the second block control circuit 230b, and the third block control circuit 230c may manage the battery cells of the first battery block 210a, the second battery block 210b, and the third battery block 210c, and control the first balancing circuit 220a, the second balancing circuit 220b, and the third balancing circuit 220c.

[0067] The battery pack 200 includes a rack fuse F R Also includes rack fuse F R may be connected between the first battery block 210a, the second battery block 210b, and the third battery block 210c and the first pack terminal PT1 or the second pack terminal PT2. R When a current of a preset magnitude or more flows, the rack fuse F melts down and cuts off the large current path through the first battery block 210a, the second battery block 210b, and the third battery block 210c. R When the rack fuse F is blown, R A very large reverse voltage is applied across the rack fuse F R The main controller 240 has a voltage resistance capable of withstanding a large reverse voltage. R state, i.e., rack fuse F R It is possible to sense whether the resistor is blown or not.

[0068] The battery pack 200 includes a current sensor for the main controller 240 to sense the pack current flowing through the first battery block 210a, the second battery block 210b, and the third battery block 210c. The current sensor is a shunt resistor R between the first battery block 210a, the second battery block 210b, and the third battery block 210c and the second pack terminal PT2 or the first pack terminal PT1. S It is also.

[0069] The main controller 240 is connected to a shunt resistor R S The main controller 240 can sense the magnitude of the pack current based on the voltage across the shunt resistor R S If a pack current exceeding a preset reference value is detected using this, it can be determined that a short circuit has occurred between first pack terminal PT1 and second pack terminal PT2.

[0070] FIG. 4 illustrates one block of the battery pack of FIG.

[0071] 4 in conjunction with FIG 3, there is illustrated a first block 201 of the battery pack 200 of FIG 3. The second block 202 and the third block 203 are also substantially identical to the first block 201.

[0072] The first battery block 210a includes battery cells C1, C2, C3, . . . , C n It also includes battery cells C1, C2, C3, ..., C n 4, the battery cells C1, C2, C3, ..., C4 may be connected in series between the first battery terminal BT1 and the second battery terminal BT2. n Each may be collectively referred to as a battery cell C.

[0073] The battery cell C includes an electrode assembly connected in series between a positive terminal and a negative terminal, and a cell fuse F. C The electrode assembly also includes a positive electrode E connected to a positive terminal. P , a negative electrode E connected to the negative terminal N , and positive electrode EP and negative electrode E N Located between the positive electrode E P and negative electrode E N The separator also includes a separator that separates the two components from contacting each other.

[0074] Self-Fuse F C If a current exceeding a preset level flows, the fuse melts down and cuts off the current path through the battery cell C, thereby preventing serious dangers such as the electrode assembly in the battery cell C catching fire or exploding.

[0075] 3, a very large pack current will flow between the first pack terminal PT1 and the second pack terminal PT2. If a very large pack current flows due to a short circuit, the rack fuse F R However, the battery cells C1, C2, C3, ..., C4 of the first battery block 210a, the second battery block 210b, and the third battery block 210c are blown off first. n Cell Fuse F C Any one of the rack fuses F R If the blown cell fuse F C At both ends of the cell fuse F C Such a reverse voltage will occur at the cell fuse F C An arc is generated in the battery cell C, damaging the separator of the battery cell C and causing the positive electrode E of the electrode assembly to P and negative electrode E N and may come into contact with each other.

[0076] The first balancing circuit 220a is a balancing circuit for balancing the battery cells C1, C2, C3, . . . , C n Multiple balancing resistors R B1 ,R B2 ,R B3 ,…,R Bn and multiple balancing switches S B1 ,SB2 ,S B3 ,…,S Bn As shown in FIG. 4, the positive and negative terminals of the first battery cell C1 are connected in series with a first balancing resistor R B1 and the first balancing switch S B1 The first balancing switch S B1 When is turned on, the first battery cell C1 and the first balancing resistor R B1 form a closed circuit, and both terminals of the first battery cell C1 are connected to the first balancing resistor R B1 is directly connected to both ends of the

[0077] The first block control circuit 230a controls the battery cells C1, C2, C3, . . . , C in the first battery block 210a. n The first block control circuit 230a may monitor the cell voltages and temperatures of the battery cells C1, C2, C3, ..., C4 in the first battery block 210a using the first balancing circuit 220a. n The first block control circuit 230a may perform cell balancing to equalize the cell voltages. The first block control circuit 230a may be referred to as an analog front end (AFE).

[0078] The first block control circuit 230a is connected to the battery terminals T0, T1, T2, T3, . . . n-1 ,T n The first battery block 210a may have battery cells C1, C2, C3, ..., C n are battery terminals T0, T1, T2, T3, …, T n-1 ,T n For example, a first battery cell C1 may be coupled between battery terminals T0 and T1.

[0079] The first block control circuit 230a also includes a multiplexer (MUX) 231. The multiplexer (MUX) 231 is connected to the battery terminals T0, T1, T2, T3, ..., T n-1 ,T nThe multiplexer (MUX) 231 selects two adjacent battery terminals from the battery cells C1, C2, C3, ..., C4 in the first battery block 210a. n In the above embodiment, two battery terminals may be selected to be connected to any one of the battery cells.

[0080] The first block control circuit 230a also includes an analog-to-digital converter (ADC) 232. The ADC 232 can convert the voltage between two battery terminals selected by a multiplexer (MUX) 231 into a digital value. The ADC 232 can convert the voltage between the battery cells C1, C2, C3, ..., C4 in the first battery block 210a into a digital value. n In the above, the cell voltage of the battery cell selected by the multiplexer (MUX) 231 can be converted into a digital value.

[0081] The first block control circuit 230a also includes a block controller 233. The block controller 233 may receive the digital value output from the ADC 232. The block controller 233 may control the battery cells C1, C2, C3, ..., C4 in the first battery block 210a. n , C1, C2, C3, ..., C4, ..., C5, ..., C6, ..., C7, ..., C8, ..., C9, ..., C10, ..., C11, ..., C12, ..., C13, ..., C14, ..., C15, ..., C16, ..., C17, ..., C18, ..., C19, ..., C20, ..., C21, ..., C22, ..., C23, ..., C31, ..., C32, ..., C4, ..., C5, ..., C6, ..., C7, ..., C8, ..., C9, ..., C11, ..., C12, ..., C13, ..., C14, ..., C15, ..., C16, ..., C17, ..., C18, ..., C19, ..., C20, ..., C21, ..., C31, ..., C32, ..., C33, ..., C3 n The cell voltages of both the 100 and 200 cells may be collected.

[0082] The first block control circuit 230a also includes a balancing control circuit 234. The balancing control circuit 234, under the control of the block controller 233, controls the balancing switch S B1 ,S B2 ,S B3 ,…,S Bn The block controller 233 may control the battery cells C1, C2, C3, ..., C4 according to a preset cell balancing standard. n, which battery cell needs to be balanced. For example, assume that the first battery cell C1 is a battery cell that needs strong balancing. The block controller 233 controls the balancing control circuit 234 to perform cell balancing on the first battery cell C1, and the balancing control circuit 234 switches the first balancing switch S corresponding to the first battery cell C1 between the first battery cell C1 and the first balancing switch S2. B1 The power stored in the first battery cell C1 is turned on by the first balancing switch S B1 The first balancing resistor R B1 By discharging through the first battery cell C1, the cell voltage of the first battery cell C1 can be reduced.

[0083] The main controller 240 senses the pack current flowing through the battery 210 between the first pack terminal PT1 and the second pack terminal PT2 via the current sensor, and controls the balancing switches S of the first block 201, the second block 202, and the third block 203. B1 ,S B2 ,S B3 ,…,S Bn The main controller 240 may be configured to control the rack fuses F R According to the present invention, when the main controller 240 detects a short circuit between the first pack terminal PT1 and the second pack terminal PT2 based on the pack current, the main controller 240 turns off all the balancing switches S of the first block 201, the second block 202, and the third block 203. B1 ,S B2 ,S B3 ,…,S Bn In order to turn on all the balancing switches, the first block 201 may transmit a command to the block controller 233 of the first block 201 to turn on all the balancing switches.

[0084] The block controller 233 of the first block 201 controls all the balancing switches S B1 ,S B2 ,S B3 ,…,S BnThe block controller 233 of the second block 202 may also turn on all the balancing switches S of the second block 202 in response to the command. B1 ,S B2 ,S B3 ,…,S Bn The block controller 233 of the third block 203 may also turn on all the balancing switches S of the second block 202 in response to the command. B1 ,S B2 ,S B3 ,…,S Bn may be turned on.

[0085] A short circuit causes rack fuse F R If the rack fuse F blows first, R Since the rack fuse F is designed to have a withstand voltage higher than the reverse voltage corresponding to the pack voltage, the battery pack 200 can be safely protected. R More Cell Fuse F C For example, the cell fuse F of the first battery cell C1 of the first block 201 C Even if the balancing switches S are blown first, all the balancing switches S are turned on by the control of the main controller 240. B1 ,S B2 ,S B3 ,…,S Bn is turned on, the reverse voltage applied to the first battery cell C1 is B1 When a voltage is applied across both ends of the first battery cell C1, the cell fuse F C Even if a short circuit occurs at the load end of the battery pack 200, the battery pack 200 and a user who uses the battery pack 200 can be safely protected.

[0086] 5A and 5B illustrate a perspective view and a cross-sectional view of a cylindrical battery cell installed in a battery pack according to one embodiment of the present invention.

[0087] 5A and 5B, the cylindrical battery cell 1100 includes a cylindrical can 1110, an electrode assembly 1120, and a cap assembly 1140. The cylindrical battery cell 1100 further includes a center pin 1130. The cap assembly 1140 also performs a current interruption operation in the cylindrical battery cell 1100, and therefore may be referred to as a current interrupt device.

[0088] The cylindrical can 1110 also includes a generally circular bottom 1111 and a cylindrical sidewall 1112 extending upwardly from around the bottom 1111. During the manufacturing process of the cylindrical battery cell 1100, the top of the cylindrical can 1110 is opened and the electrode assembly 1120 and center pin 1130, along with the electrolyte, may be inserted into the cylindrical can 1110. The cylindrical can 1110 may be made of, for example, steel, stainless steel, aluminum, an aluminum alloy, or equivalents.

[0089] The cylindrical can 1110 also includes a beading part 1113 that is recessed inward from the bottom of the side of the cap assembly 1140 to prevent the cap assembly 1140 from falling off to the outside, and a crimping part 1114 that is bent inward from the top of the side of the cap assembly 1140.

[0090] The electrode assembly 1120 may be housed inside the cylindrical can 1110. The electrode assembly 1120 may include a negative electrode plate 1121 in which a negative electrode active material (e.g., graphite, carbon, etc.) is coated on a negative electrode current collector, a positive electrode plate 1122 in which a positive electrode active material (e.g., transition metal oxide (LiCoO2, LiNiO2, LiMn2O4, etc.)) is coated on a positive electrode current collector, and a separator 1123 between the negative electrode plate 1121 and the positive electrode plate 1122 to prevent contact or short between them and to allow only the movement of lithium ions. The negative electrode plate 1121, the positive electrode plate 1122, and the separator 1123 may be wound up in an approximately cylindrical shape. For example, but not limited to, the negative electrode current collector may be made of copper (Cu) foil, the positive electrode current collector may be made of aluminum (Al) foil, and the separator may be made of polyethylene (PE) or polypropylene (PP).

[0091] A negative electrode tab 1124 protruding a certain length from the bottom may be welded to the negative electrode plate 1121, and a positive electrode tab 1125 protruding a certain length from the top may be welded to the positive electrode plate 1122, or vice versa. In addition, for example, but not limited to, the negative electrode tab 1124 may be made of copper (Cu) or nickel (Ni), and the positive electrode tab 1125 may be made of aluminum (Al).

[0092] A cell fuse 1125f may be formed in the positive electrode tab 1125. The cell fuse 1125f is a part of the positive electrode tab 1125, and is a part having a narrower width or a thinner thickness than other parts of the positive electrode tab 1125. According to another example, a cell fuse may also be formed in the negative electrode tab 1224.

[0093] The negative electrode tab 1124 of the electrode assembly 1120 may be welded to the bottom 1111 of the cylindrical can 1110. Thus, the cylindrical can 1110 may act as a negative electrode. Conversely, it goes without saying that the positive electrode tab 1125 may be welded to the bottom 1111 of the cylindrical can 1110, in which case the cylindrical can 1110 may act as a positive electrode.

[0094] A first insulating plate 1126 may be interposed between the electrode assembly 1120 and the bottom 1111. The first insulating plate 1126 prevents the electrode assembly 1120, particularly the positive electrode plate 1122, from being electrically contacted with the bottom 1111. The first insulating plate 1126 may have a first hole 1126a located at the center and a second hole 1126b located apart from the first hole 1126a. The first hole 1126a quickly moves gas to the upper portion through the center pin 1130 when a large amount of gas is generated due to an abnormality in the cylindrical battery cell 1100, and the second hole 1126b allows the negative electrode tab 1124 to pass through and be welded to the bottom 1111.

[0095] A second insulating plate 1127 may be interposed between the electrode assembly 1120 and the cap assembly 1140. The second insulating plate 1127 prevents the electrode assembly 1120, particularly the negative electrode plate 1121, from being electrically contacted with the cap assembly 1140. The second insulating plate 1127 may have a first hole 1127a located at the center and a plurality of second holes 1127b located outside the first hole 1127a. The first hole 1127a serves to quickly move gas to the cap assembly 1140 when a large amount of gas is generated due to an abnormality in the cylindrical battery cell 1100, and one of the plurality of second holes 1127b serves to allow the positive electrode tab 1125 to penetrate and be welded to the cap assembly 1140. In addition, the remaining second holes 1127b function to allow the electrolyte to flow quickly to the electrode assembly 1120 during an electrolyte injection process.

[0096] The first hole 1126a of the first insulating plate 1126 and the first hole 1127a of the second insulating plate 1127 have a diameter smaller than the diameter of the center pin 1130, thereby preventing the center pin 1130 from coming into electrical contact with the bottom 1111 of the cylindrical can 1110 or the cap assembly 1140 due to external impact.

[0097] The center pin 1130 may be in the form of a hollow circular pipe and may be coupled to approximately the center of the electrode assembly 1120. The center pin 1130 may be made of, for example, steel, stainless steel, aluminum, an aluminum alloy, or polybutylene terephthalate. The center pin 1130 serves to suppress deformation of the electrode assembly 1120 during charging and discharging of the battery, and serves as a passage for gas generated inside the cylindrical battery cell 1100. It goes without saying that the center pin 1130 may be omitted in some cases.

[0098] The cap assembly 1140 also includes a top plate 1141, a middle plate 1142, an insulating plate 1143, and a bottom plate 1144. The middle plate 1142 is located below the top plate 1141 and has a substantially flat shape. The insulating plate 1143 may be formed in a circular ring shape having a certain width when viewed from below. Also, the insulating plate 1143 serves to insulate the middle plate 1142 and the bottom plate 1144 from each other. For example, but not limited to, the insulating plate 1143 may be interposed between the middle plate 1142 and the bottom plate 1144 and ultrasonically welded.

[0099] FIG. 6 is a partial perspective view illustrating the structure of a pouch-type battery cell mounted in a battery pack according to one embodiment of the present invention.

[0100] Referring to FIG. 6, a pouch-type battery cell 1200 includes an electrode assembly 1210 and a pouch 1230 that accommodates the electrode assembly 1210 .

[0101] The electrode assembly 1210 includes a negative electrode plate 1212 as a first electrode plate, a positive electrode plate 1214 as a second electrode plate, and a separator 1216 interposed therebetween. The negative electrode plate 1212 includes a negative electrode tab 1212a electrically connected to the negative electrode uncoated portion, and the positive electrode plate 1214 includes a positive electrode tab 1214a electrically connected to the positive electrode uncoated portion. The negative electrode tab 1212a and the positive electrode tab 1214a are welded to a negative electrode lead 1252 and a positive electrode lead 1254 of an external terminal, and are electrically connected to the outside. A tab film 1256 is attached to the negative electrode lead 1252 and the positive electrode lead 1254 for insulation from the pouch 1230.

[0102] A cell fuse 1254f may be formed in the positive electrode lead 1254. The cell fuse 1254f is a part of the positive electrode lead 1254, and is a part having a narrower width or a thinner thickness than other parts of the positive electrode lead 1254. According to another example, the cell fuse may be formed in the positive electrode tab 1214a. According to yet another example, the cell fuse may be formed in the negative electrode tab 1212a or the negative electrode lead 1252.

[0103] The pouch 1230 is sealed with the electrode assembly 1210 housed therein, with the sealing portions 1232 at the edges abutting against each other. At this time, the pouch 1230 is sealed with the tab film 1256 disposed between the sealing portions 1232. As shown in FIG. 6, a configuration in which the tab film 1256 is attached to each of the negative electrode tab 1212a and the positive electrode tab 1214a is defined as a "separate tab film." Such a sealing structure may be defined as a separate sealing structure.

[0104] The sealing portion 1232 of the pouch 1230 is made of a heat-sealing material, and is structured so that heat-sealing layers are bonded together to form a seal. Since the heat-sealing material generally has a weak adhesiveness to metal, a thin tab film 1256 is attached to the tab and then fused to the pouch 1230. However, the separate sealing structure requires that the tab film 1256 be attached to each tab, welded to the tab, and then further heat-sealed to the pouch 1230, resulting in a problem of reduced workability and productivity.

[0105] FIG. 7A is a perspective view of a prismatic battery cell mounted in a battery pack according to one embodiment of the present invention, and FIG. 7B is a cross-sectional view taken along the cut line (II-II) in FIG. 7A.

[0106] 7A and 7B, a rectangular battery cell 1300 includes at least one electrode assembly 1310 wound between a positive electrode 1311 and a negative electrode 1312 with an insulating separator 1313 interposed therebetween, a case 1320 containing the electrode assembly 1310, and a cap assembly 1330 coupled to an opening of the case 1320.

[0107] The prismatic battery cell 1300 is a lithium ion battery cell having a prismatic shape, and will be described as an example, however, the present invention is not limited thereto, and the prismatic battery cell 1300 may be a battery cell of various shapes, such as a lithium polymer battery cell.

[0108] The positive electrode 1311 and the negative electrode 1312 also include coated portions, which are areas where an active material is applied to a current collector formed from a thin metal foil, and uncoated portions 1311a, 1312a, which are areas where the active material is not coated.

[0109] The positive electrode 1311 and the negative electrode 1312 are wound up after being sandwiched between them by a separator 1313, which is an insulator. However, the present invention is not limited to this, and the electrode assembly 1310 may also have a structure in which a positive electrode and a negative electrode made of a plurality of sheets are stacked on top of each other with a separator sandwiched therebetween.

[0110] The case 1320 forms the overall appearance of the prismatic battery cell 1300 and may be made of a conductive metal such as aluminum, an aluminum alloy, or nickel-plated steel, and may provide a space in which the electrode assembly 1310 is housed.

[0111] The cap assembly 1330 may also include a cap plate 1331 that covers the opening of the case 1320, and the case 1320 and the cap plate 1331 may be formed of a conductive material. Here, a positive electrode terminal 1321 and a negative electrode terminal 1322 electrically connected to the positive electrode 1311 and the negative electrode 1312, respectively, may be provided to penetrate the cap plate 1331 and protrude outward.

[0112] The outer circumferential surfaces of the upper pillars of the positive terminal 1321 and the negative terminal 1322 protruding out of the cap plate 1331 may be threaded and fixed to the cap plate 1331 with nuts. However, the present invention is not limited thereto, and the positive terminal 1321 and the negative terminal 1322 may be riveted or welded to the cap plate 1331 using a rivet structure.

[0113] The cap plate 1331 is made of a thin plate and is coupled to the opening of the case 1320. The cap plate 1331 may have an electrolyte injection hole 1332 to which a sealing plug 1333 may be provided, and a vent portion 1334 having a notch 1334a formed therein.

[0114] The positive electrode terminal 1321 and the negative electrode terminal 1322 may be electrically connected to a current collector including a first current collector 1340 and a second current collector 1350 (hereinafter referred to as a positive electrode current collector and a negative electrode current collector) welded to the positive electrode uncoated portion 1311a or the negative electrode uncoated portion 1312a. For example, the positive electrode terminal 1321 and the negative electrode terminal 1322 may be connected to the positive electrode collector 1340 and the negative electrode collector 1350 by welding. However, the present invention is not limited thereto, and the positive electrode terminal 1321 and the negative electrode terminal 1322, and the positive electrode collector 1340 and the negative electrode collector 1350 may be integrally connected to each other.

[0115] A cell fuse 1340f may be formed in the positive electrode current collector 1340. The cell fuse 1340f is a part of the positive electrode current collector 1340, and is also a part having a narrower width or a thinner thickness than other parts of the positive electrode current collector 1340. According to another example, a cell fuse may be formed in the negative electrode current collector 1350.

[0116] In addition, an insulating member may be interposed between the electrode assembly 1310 and the cap plate 1331. Here, the insulating member may include a first lower insulating member 1360 and a second lower insulating member 1370, and each of the first lower insulating member 1360 and the second lower insulating member 1370 may be interposed between the electrode assembly 1310 and the cap plate 1331.

[0117] According to the present embodiment, one end of a separating member that can be provided to face one side of the electrode assembly 1310 may be provided between the insulating member and the positive electrode terminal 1321 or the negative electrode terminal 1322. Here, the separating member also includes a first separating member 1380 and a second separating member 1390. Therefore, one end of the first separating member 1380 and the second separating member 1390 that can be provided to face one side of the electrode assembly 1310 may be provided between the first lower insulating member 1360 and the second lower insulating member 1370 and the positive electrode terminal 1321 and the negative electrode terminal 1322.

[0118] Finally, the positive electrode terminal 1321 and the negative electrode terminal 1322 welded to the positive electrode collector 1340 and the negative electrode collector 1350 can be coupled to one end of the first lower insulating member 1360 and the second lower insulating member 1370, as well as the first separating member 1380 and the second separating member 1390.

[0119] The specific embodiments shown and described herein are illustrative examples and are not intended to limit the scope of the present invention in any manner. For the sake of brevity, descriptions of conventional electronic configurations, control systems, software, and other functional aspects of the system may be omitted. In addition, the wire connections or connecting members between components shown in the drawings are illustrative of functional connections and / or physical or circuit connections, and may be embodied by various alternative or additional functional connections, physical connections, or circuit connections in an actual device.

[0120] In describing an embodiment (particularly in the claims), the use of the term "said" and similar indicators may refer to both the singular and the plural. In addition, in one embodiment, when a range is described, it includes the invention to which each individual value within the range is applied (unless otherwise stated), and each individual value constituting the range is described in the detailed description of the invention. Unless otherwise expressly stated or otherwise stated, the steps constituting the method according to the present invention may be performed in any suitable order. The order in which the steps are described is not necessarily intended to limit the invention.

[0121] In the present invention, the use of all examples or exemplary terms (e.g., "etc.", etc.) is merely for the purpose of describing the present invention in detail, and the scope of the present embodiment is not limited by the above examples or exemplary terms, since it is not limited by the scope of the claims. In addition, a person skilled in the art will understand that various modifications, combinations, and changes can be made within the scope of the claims or their equivalents, depending on design conditions and factors.

[0122] Although exemplary embodiments are presented herein and specific terms are used, these terms should be construed as generally descriptive and not limiting. In some cases, as would be apparent to one of ordinary skill in the art at the time of filing of this application, features and / or components described in connection with a particular embodiment may be used alone or in combination with features and / or components described in connection with other embodiments, unless specifically stated otherwise. Therefore, the spirit of the present invention is not limited to the above-described embodiment, and the scope of the following claims, as well as all equivalents or equivalent modifications thereto, are within the spirit of the present invention. [Explanation of symbols]

[0123] 10,20 Load 100,200 Battery Pack 110 Battery 120 Balancing Circuit 130 Controller 201,202,203 Blocks 240 Main Controller

Claims

1. a plurality of battery cells between the first pack terminal and the second pack terminal; a plurality of balancing resistors respectively coupled to the plurality of battery cells; a plurality of balancing switches respectively connected to the plurality of battery cells and the plurality of balancing resistors, each of which, when turned on, connects a corresponding battery cell to a corresponding balancing resistor to form a closed circuit; a rack fuse between the plurality of battery cells and the first pack terminal or the second pack terminal; a current sensor between the plurality of battery cells and the first pack terminal or the second pack terminal; a controller configured to sense a pack current between the first pack terminal and the second pack terminal via the current sensor and to control the plurality of balancing switches; the controller is configured to detect a short circuit between the first pack terminal and the second pack terminal based on the pack current and turn on all of the balancing switches.

2. Each of the plurality of battery cells is a first cell terminal and a second cell terminal; an electrode assembly including a positive electrode connected to the first cell terminal, a negative electrode connected to the second cell terminal, and a separator between the positive electrode and the negative electrode; a cell fuse between the electrode assembly and the first cell terminal or the second cell terminal; 2. The battery pack of claim 1, further comprising:

3. 2. The battery pack of claim 1, wherein the controller detects the short circuit based on the pack current exceeding a preset reference value.

4. 4. The battery pack of claim 3, wherein the controller is configured to detect the release of the short circuit when all of the balancing switches are turned on, and to determine whether the rack fuse is blown.

5. 5. The battery pack of claim 4, wherein the controller detects the release of the short circuit based on the pack current being reduced to or below the preset reference value.

6. The battery pack of claim 4 , wherein the controller is configured to turn off all of the balancing switches if the rack fuse is not blown.

7. a plurality of battery blocks connected between the first pack terminal and the second pack terminal, each of the battery blocks having the plurality of battery cells; a plurality of balancing circuits each including the plurality of balancing resistors and the plurality of balancing switches; a plurality of block control circuits each controlling the plurality of balancing switches of a corresponding balancing circuit; 2. The battery pack of claim 1, further comprising: a main controller configured to sense the pack current and a state of the rack fuse and to control the plurality of block control circuits.

8. 8. The battery pack according to claim 7, wherein the controller includes the plurality of block control circuits and the main controller.

9. 8. The battery pack of claim 7, wherein the main controller detects a short circuit between the first pack terminal and the second pack terminal based on the pack current, and transmits a command to the block control circuits to turn on all of the balancing switches of the balancing circuits.

10. The plurality of block control circuits include Collecting cell voltages of the plurality of battery cells of a corresponding battery block; 8. The battery pack according to claim 7, further configured to individually control the balancing switches of the corresponding balancing circuits to equalize cell voltages of the battery cells.

11. A method for protecting a battery pack, comprising: a plurality of battery cells between a first pack terminal and a second pack terminal; a plurality of balancing resistors respectively coupled to the plurality of battery cells; a plurality of balancing switches respectively coupled to the plurality of battery cells and the plurality of balancing resistors, each of which, when turned on, connects a corresponding battery cell to a corresponding balancing resistor to form a closed circuit; a rack fuse between the plurality of battery cells and the first pack terminal or the second pack terminal; a current sensor between the plurality of battery cells and the first pack terminal or the second pack terminal; and a controller configured to control the plurality of balancing switches, sensing a pack current between the first pack terminal and the second pack terminal via the current sensor; sensing a short circuit between the first pack terminal and the second pack terminal based on the pack current; and turning on all of the balancing switches based on the detection of the short circuit.

12. The step of sensing a short circuit comprises: comparing the pack current with a preset reference value; 12. The method of claim 11, further comprising: determining that the short circuit has occurred if the pack current exceeds a preset reference value.

13. after turning on all of the balancing switches, detecting that the short circuit has been removed; The method of claim 12, further comprising: if the short circuit is removed, determining whether the rack fuse is blown.

14. The step of sensing removal of the short circuit includes: comparing the pack current with the preset reference value; 14. The method of claim 13, further comprising: determining to release the short circuit if the pack current is reduced to or below the preset reference value.

15. 14. The method of claim 13, further comprising turning off all of the balancing switches if it is determined that the rack fuse is not blown after the step of determining whether the rack fuse is blown.

16. Each of the plurality of battery cells is a first cell terminal and a second cell terminal; an electrode assembly including a positive electrode connected to the first cell terminal, a negative electrode connected to the second cell terminal, and a separator between the positive electrode and the negative electrode; The method of claim 11, further comprising a cell fuse between the electrode assembly and the first cell terminal or the second cell terminal.

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