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Secondary battery protection circuit and battery pack

A technology for secondary batteries and protection circuits, which is used in charging/discharging secondary batteries, repairing/maintaining secondary batteries, and battery pack components.

Inactive Publication Date: 2011-06-01
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0024] In addition, such as Figure 52 or Figure 53 shows that in a structure that seeks to protect the secondary battery from overcharge by connecting a temperature switch that operates based on the temperature of a bimetal switch or a PTC element, etc., in series with the secondary battery, since the accuracy of detecting overcharge is low, such as When using an inferior charging device with low charging voltage control accuracy to charge the battery pack, if the secondary battery is continuously charged with a charging current that does not cause the temperature to rise sharply, the temperature switch may not operate and the secondary battery may be damaged. However, if the battery is overcharged, the characteristics of the secondary battery will deteriorate, or the battery will swell or deform, etc.

Method used

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  • Secondary battery protection circuit and battery pack
  • Secondary battery protection circuit and battery pack
  • Secondary battery protection circuit and battery pack

Examples

Experimental program
Comparison scheme
Effect test

no. 1 example

[0087] The protection circuit 5 is arranged inside the external terminal connection unit 3, and includes connection terminals T1 to T4 (first to fourth connection terminals), a bimetal switch (bimetal switch) (thermal switch) SW1, a thermal fuse F1, and a comparator CMP1 , a reference voltage source E1, a resistor R1, a transistor Q1, and a heater (first heater) R2. The connection terminal T1 and the connection terminal T2 are connection terminals for connecting a charging device (not shown) for charging the secondary battery 6 and / or a load device driven by the discharge current output from the secondary battery 6 . Load equipment refers to various electrical equipment driven by batteries, including mobile phones, digital cameras, video cameras, portable personal computers, and electric tools.

[0088] The bimetallic switch SW1 is turned off when it exceeds the preset predetermined operating temperature Tsw1, and when the charging and discharging current of the secondary batt...

no. 2 example

[0120] Accordingly, it is possible to save Figure 4 The printed circuit board PR1 in the protection circuit 5 is shown so that the protection circuit 5a can be miniaturized by a portion corresponding to the thickness of the printed circuit board PR1.

[0121] In addition, as shown in FIG. 5( b ), inside the housing 31 of the external terminal connection unit 3 , for example, support members 32 and 33 protrudingly formed by integral molding with the housing 31 are provided. And the wiring pattern P4 drawn from the top of the support member 32 is connected to the connection terminal T1 provided on the outer surface of the case 31 , for example, through the cylindrical metal member 34 penetrating the case 31 . In addition, on the top of the supporting member 32, one end of the movable slice 35 constituting the bimetal switch SW1 is connected and fixed to the wiring pattern P4 by, for example, spot welding. The other end of the movable slice 35 is provided with a contact point 3...

no. 3 example

[0142] The positive pole of the secondary battery 64 is connected to the - terminal of the comparator CMP13, the + terminal of the comparator CMP13 is connected to the positive pole of the reference voltage source E13, the negative pole of the reference voltage source E13 is connected to the negative pole of the secondary battery 64, and the output of the comparator CMP13 The terminal is connected to the input terminal of the NAND gate 7 .

[0143] The positive pole of the secondary battery 65 is connected to the - terminal of the comparator CMP14, the + terminal of the comparator CMP14 is connected to the positive pole of the reference voltage source E14, the negative pole of the reference voltage source E14 is connected to the negative pole of the secondary battery 65, and the output of the comparator CMP14 The terminal is connected to the input terminal of the NAND gate 7 . Furthermore, the output terminal of the NAND gate 7 is connected to the signal input terminal of the ...

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PUM

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Abstract

A protection circuit is provided for protecting a secondary battery from overcharging and excessive discharge current by a simple circuit. The protection circuit is provided with a connecting terminal (T3) for connecting the secondary battery (6); a connecting terminal (T1) for connecting a loading device driven by a discharge current from a recharging device which recharges the secondary battery(6) and / or a discharge current from the secondary battery (6); a bimetal switch (SW1) which is arranged between the connecting terminal (T1) and the connecting terminal (T3) and turns off when a temperature exceeds a previously set prescribed temperature; a heater (R2) for heating the bimetal switch (SW1); and an integrated circuit (IC1) which permits the heater (R2) to generate heat when a voltage applied to the connecting terminal (T3) by the secondary battery (6) exceeds a previously set reference voltage and turns off the bimetal switch (SW1).

Description

technical field [0001] The invention relates to a protection circuit for protecting a secondary battery from overcharging or excessive discharge current, a thermal protection switch device and a battery assembly equipped with the protection circuit and the thermal protection switch device. Background technique [0002] Figure 51 It is a circuit diagram showing the structure of the battery pack related to the background art. Figure 51 The illustrated battery pack 1001 includes a protection circuit 1002 and a secondary battery 1003 . The secondary battery 1003 is, for example, a lithium ion (lithium-ion) secondary battery, a lithium polymer (lithium polymer) secondary battery, a nickel hydrogen (nickel hydrogen) secondary battery, or a nickel cadmium (nickel cadmium) secondary battery, etc. Rechargeable secondary battery. If the above-mentioned secondary battery is overcharged or discharged with an excessively large current, characteristics such as cycle life may deterio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J7/00H01M2/10H01M2/34H01M10/44H02H7/18
CPCY02E60/12Y02E60/10
Inventor 森猪一郎
Owner PANASONIC CORP